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Benchmarking Working Group                                     M. Bustos
Internet-Draft                                                      IXIA
Expires: February 2, 2006                                   T. Van Herck
                                                           Cisco Systems
                                                                 M. Kaeo
                                                    Double Shot Security
                                                             August 2005


               Terminology for Benchmarking IPsec Devices
                     draft-ietf-bmwg-ipsec-term-06

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   By submitting this Internet-Draft, each author represents that any
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   This Internet-Draft will expire on February 2, 2006.

Copyright Notice

   Copyright (C) The Internet Society (2005).  All Rights Reserved.

Abstract

   This purpose of this document is to define terminology specific to
   measuring the performance of IPsec devices.  It builds upon the
   tenets set forth in [RFC1242], [RFC2544], [RFC2285] and other IETF
   Benchmarking Methodology Working Group (BMWG) documents used for
   benchmarking routers and switches.  This document seeks to extend
   these efforts specific to the IPsec paradigm.  The BMWG produces two
   major classes of documents: Benchmarking Terminology documents and



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   Benchmarking Methodology documents.  The Terminology documents
   present the benchmarks and other related terms.  The Methodology
   documents define the procedures required to collect the benchmarks
   cited in the corresponding Terminology documents.

Table of Contents

   1.   Introduction . . . . . . . . . . . . . . . . . . . . . . . .   4
   2.   IPsec Fundamentals . . . . . . . . . . . . . . . . . . . . .   4
     2.1  IPsec Operation  . . . . . . . . . . . . . . . . . . . . .   6
       2.1.1  Security Associations  . . . . . . . . . . . . . . . .   6
       2.1.2  Key Management . . . . . . . . . . . . . . . . . . . .   6
   3.   Document Scope . . . . . . . . . . . . . . . . . . . . . . .   8
   4.   Definition Format  . . . . . . . . . . . . . . . . . . . . .   9
   5.   Key Words to Reflect Requirements  . . . . . . . . . . . . .   9
   6.   Existing Benchmark Definitions . . . . . . . . . . . . . . .   9
   7.   Definitions  . . . . . . . . . . . . . . . . . . . . . . . .  10
     7.1  IPsec  . . . . . . . . . . . . . . . . . . . . . . . . . .  10
     7.2  ISAKMP . . . . . . . . . . . . . . . . . . . . . . . . . .  10
     7.3  IKE  . . . . . . . . . . . . . . . . . . . . . . . . . . .  11
       7.3.1  IKE Phase 1  . . . . . . . . . . . . . . . . . . . . .  12
       7.3.2  IKE Phase 1 Main Mode  . . . . . . . . . . . . . . . .  13
       7.3.3  IKE Phase 1 Aggressive Mode  . . . . . . . . . . . . .  13
       7.3.4  IKE Phase 2  . . . . . . . . . . . . . . . . . . . . .  14
       7.3.5  Phase 2 Quick Mode . . . . . . . . . . . . . . . . . .  14
     7.4  Security Association (SA)  . . . . . . . . . . . . . . . .  15
     7.5  Selectors  . . . . . . . . . . . . . . . . . . . . . . . .  15
     7.6  IPsec Device . . . . . . . . . . . . . . . . . . . . . . .  16
       7.6.1  Initiator  . . . . . . . . . . . . . . . . . . . . . .  17
       7.6.2  Responder  . . . . . . . . . . . . . . . . . . . . . .  17
       7.6.3  IPsec Client . . . . . . . . . . . . . . . . . . . . .  18
       7.6.4  IPsec Server . . . . . . . . . . . . . . . . . . . . .  19
     7.7  Tunnels  . . . . . . . . . . . . . . . . . . . . . . . . .  19
       7.7.1  IPsec Tunnel . . . . . . . . . . . . . . . . . . . . .  19
       7.7.2  Configured Tunnel  . . . . . . . . . . . . . . . . . .  21
       7.7.3  Established Tunnel . . . . . . . . . . . . . . . . . .  22
       7.7.4  Active Tunnel  . . . . . . . . . . . . . . . . . . . .  22
     7.8  Iterated Tunnels . . . . . . . . . . . . . . . . . . . . .  23
       7.8.1  Nested Tunnels . . . . . . . . . . . . . . . . . . . .  23
       7.8.2  Transport Adjacency  . . . . . . . . . . . . . . . . .  24
     7.9  Transform protocols  . . . . . . . . . . . . . . . . . . .  25
       7.9.1  Authentication Protocols . . . . . . . . . . . . . . .  26
       7.9.2  Encryption Protocols . . . . . . . . . . . . . . . . .  26
     7.10   IPsec Protocols  . . . . . . . . . . . . . . . . . . . .  27
       7.10.1   Authentication Header (AH) . . . . . . . . . . . . .  27
       7.10.2   Encapsulated Security Payload (ESP)  . . . . . . . .  28
     7.11   NAT Traversal (NAT-T)  . . . . . . . . . . . . . . . . .  29
     7.12   IP Compression . . . . . . . . . . . . . . . . . . . . .  29



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     7.13   Security Context . . . . . . . . . . . . . . . . . . . .  30
   8.   Framesizes . . . . . . . . . . . . . . . . . . . . . . . . .  32
     8.1  Layer3 clear framesize . . . . . . . . . . . . . . . . . .  32
     8.2  Layer3 encrypted framesize . . . . . . . . . . . . . . . .  33
     8.3  Layer2 clear framesize . . . . . . . . . . . . . . . . . .  34
     8.4  Layer2 encrypted framesize . . . . . . . . . . . . . . . .  34
   9.   Performance Metrics  . . . . . . . . . . . . . . . . . . . .  35
     9.1  Tunnels Per Second (TPS) . . . . . . . . . . . . . . . . .  35
     9.2  Tunnel Rekeys Per Seconds (TRPS) . . . . . . . . . . . . .  36
     9.3  Tunnel Attempts Per Second (TAPS)  . . . . . . . . . . . .  36
   10.  Test Definitions . . . . . . . . . . . . . . . . . . . . . .  37
     10.1   Throughput . . . . . . . . . . . . . . . . . . . . . . .  37
       10.1.1   IPsec Tunnel Throughput  . . . . . . . . . . . . . .  37
       10.1.2   IPsec Tunnel Encryption Throughput . . . . . . . . .  38
       10.1.3   IPsec Tunnel Decryption Throughput . . . . . . . . .  38
     10.2   Latency  . . . . . . . . . . . . . . . . . . . . . . . .  39
       10.2.1   IPsec Tunnel Latency . . . . . . . . . . . . . . . .  39
       10.2.2   IPsec Tunnel Encryption Latency  . . . . . . . . . .  40
       10.2.3   IPsec Tunnel Decryption Latency  . . . . . . . . . .  41
       10.2.4   Time To First Packet . . . . . . . . . . . . . . . .  41
     10.3   Frame Loss . . . . . . . . . . . . . . . . . . . . . . .  42
       10.3.1   IPsec Tunnel Frame Loss  . . . . . . . . . . . . . .  42
       10.3.2   IPsec Tunnel Encryption Frame Loss . . . . . . . . .  43
       10.3.3   IPsec Tunnel Decryption Frame Loss . . . . . . . . .  44
       10.3.4   Phase 2 Rekey Frame Loss . . . . . . . . . . . . . .  44
     10.4   Back-to-back Frames  . . . . . . . . . . . . . . . . . .  45
       10.4.1   IPsec Tunnel Back-to-back Frames . . . . . . . . . .  45
       10.4.2   IPsec Tunnel Encryption Back-to-back Frames  . . . .  46
       10.4.3   IPsec Tunnel Decryption Back-to-back Frames  . . . .  46
     10.5   Tunnel Setup Rate Behavior . . . . . . . . . . . . . . .  47
       10.5.1   Tunnel Setup Rate  . . . . . . . . . . . . . . . . .  47
       10.5.2   Phase 1 Setup Rate . . . . . . . . . . . . . . . . .  48
       10.5.3   Phase 2 Setup Rate . . . . . . . . . . . . . . . . .  48
     10.6   Tunnel Rekey . . . . . . . . . . . . . . . . . . . . . .  49
       10.6.1   Phase 1 Rekey Rate . . . . . . . . . . . . . . . . .  49
       10.6.2   Phase 2 Rekey Rate . . . . . . . . . . . . . . . . .  50
     10.7   Tunnel Failover Time (TFT) . . . . . . . . . . . . . . .  51
     10.8   IKE DOS Resilience Rate  . . . . . . . . . . . . . . . .  51
   11.  Security Considerations  . . . . . . . . . . . . . . . . . .  52
   12.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . .  52
   13.  Contributors . . . . . . . . . . . . . . . . . . . . . . . .  52
   14.  References . . . . . . . . . . . . . . . . . . . . . . . . .  52
     14.1   Normative References . . . . . . . . . . . . . . . . . .  52
     14.2   Informative References . . . . . . . . . . . . . . . . .  55
        Authors' Addresses . . . . . . . . . . . . . . . . . . . . .  55
        Intellectual Property and Copyright Statements . . . . . . .  56





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1.  Introduction

   Despite the need to secure communications over a public medium there
   is no standard method of performance measurement nor a standard in
   the terminology used to develop such hardware and software solutions.
   This results in varied implementations which challenge
   interoperability and direct performance comparisons.  Standardized
   IPsec terminology and performance test methodologies will enable
   users to determine if the IPsec device they select will withstand
   loads of secured traffic that meet their requirements.

   To appropriately define the parameters and scope of this document,
   this section will give a brief overview of the IPsec standard:

2.  IPsec Fundamentals

   IPsec is a framework of open standards that provides data
   confidentiality, data integrity, and data origin authenticity between
   participating peers.  IPsec provides these security services at the
   IP layer.  IPsec uses IKE to handle negotiation of protocols and
   algorithms based on local policy, and to generate the encryption and
   authentication keys to be used.  IPsec can be used to protect one or
   more data flows between a pair of hosts, between a pair of security
   gateways, or between a security gateway and a host.  The IPsec
   protocol suite set of standards is documented in RFC's [RFC2401]
   through [RFC2412] and [RFC2451].  The reader is assumed to be
   familiar with these documents.  Some Internet Drafts supersede these
   RFC's and will be taken into consideration.

   IPsec itself defines the following:

   Authentication Header (AH): A security protocol, defined in
   [RFC2402], which provides data authentication and optional anti-
   replay services.  AH ensures the integrity and data origin
   authentication of the IP datagram as well as the invariant fields in
   the outer IP header.

   Encapsulating Security Payload (ESP): A security protocol, defined in
   [RFC2406], which provides confidentiality, data origin
   authentication, connectionless integrity, an anti-replay service and
   limited traffic flow confidentiality.  The set of services provided
   depends on options selected at the time of Security Association (SA)
   establishment and on the location of the implementation in a network
   topology.  ESP authenticates only headers and data after the IP
   header.

   Internet Key Exchange (IKE): A hybrid protocol which implements
   Oakley [RFC2412] and SKEME [SKEME] key exchanges inside the ISAKMP



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   framework.  While IKE can be used with other protocols, its initial
   implementation is with the IPsec protocol.  IKE provides
   authentication of the IPsec peers, negotiates IPsec security
   associations, and establishes IPsec keys.

   The AH and ESP protocols each support two modes of operation:
   transport mode and tunnel mode.  In transport mode, two hosts provide
   protection primarily for upper-layer protocols.  The cryptographic
   endpoints (where the encryption and decryption take place) are the
   source and destination of the data packet.  In IPv4, a transport mode
   security protocol header appears immediately after the IP header and
   before any higher-layer protocols (such as TCP or UDP).  In IPv6, the
   security protocol header appears after the base IP header and
   selected extension headers.  It may appear before or after
   destination options but must appear before next layer protocols
   (e.g., TCP, UDP, SCTP)

   In the case of AH in transport mode, security services are provided
   to selected portions of the IP header preceding the AH header,
   selected portions of extension headers, and selected options
   (contained in the IPv4 header, IPv6 Hop-by-Hop extension header, or
   IPv6 Destination extension headers).  Any fields in these headers/
   extension headers which are modified in transit are set to 0 before
   applying the authentication algorithm.  If a field is mutable, but
   its value at the receiving IPsec peer is predictable, then that value
   is inserted into the field before applying the cryptographic
   algorithm.

   In the case of ESP in transport mode, security services are provide
   only for the higher-layer protocols, not for the IP header or any
   extension headers preceding the ESP header.

   A tunnel is a vehicle for encapsulating packets inside a protocol
   that is understood at the entry and exit points of a given network.
   These entry and exit points are defined as tunnel interfaces.

   Both the AH and ESP protocols can be used in tunnel mode for data
   packet endpoints as well as by intermediate security gateways.  In
   tunnel mode, there is an "outer" IP header that specifies the IPsec
   processing destination, plus an "inner" IP header that specifies the
   ultimate destination for the packet.  The source address in the outer
   IP header is the initiating cryptographic endpoint; the source
   address in the inner header is the true source address of the packet.
   The security protocol header appears after the outer IP header and
   before the inner IP header.

   If AH is employed in tunnel mode, portions of the new outer IP header
   are given protection (those same fields as for transport mode,



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   described earlier in this section), as well as all of the tunneled IP
   packet (that is, all of the inner IP header is protected as are the
   higher-layer protocols).  If ESP is employed, the protection is
   afforded only to the tunneled packet, not to the new outer IP header.

2.1  IPsec Operation

2.1.1  Security Associations

   The concept of a Security Association (SA) is fundamental to IPsec.
   An SA is a relationship between two or more entities that describes
   how the entities will use security services to communicate.  The SA
   includes: an encryption algorithm, an authentication algorithm and a
   shared session key.

   Because an SA is unidirectional, two SA's (one in each direction) are
   required to secure typical, bidirectional communication between two
   entities.  The security services associated with an SA can be used
   for AH or ESP, but not for both.  If both AH and ESP protection is
   applied to a traffic stream, two (or more) SA's are created for each
   direction to protect the traffic stream.

   The SA is uniquely identified by the Security Parameter Index (SPI)
   [RFC2406].  When a system sends a packet that requires IPsec
   protection, it looks up the SA in its database and applies the
   specified processing and security protocol (AH/ESP), inserting the
   SPI from the SA into the IPsec header.  When the IPsec peer receives
   the packet, it looks up the SA in its database by destination
   address, protocol, and SPI and then processes the packet as required.

2.1.2  Key Management

   IPsec uses cryptographic keys for authentication, integrity and
   encryption services.  Both manual provisioning and automatic
   distribution of keys is supported.  IKE is specified as the public-
   key-based approach for automatic key management.

   IKE authenticates each peer involved in IPsec, negotiates the
   security policy, and handles the exchange of session keys.  IKE is a
   hybrid protocol, combining parts of the following protocols to
   negotiate and derive keying material for SA's in a secure and
   authenticated manner:

   1.  ISAKMP [RFC2408] (Internet Security Association and Key
       Management Protocol), which provides a framework for
       authentication and key exchange but does not define them.  ISAKMP
       is designed to be key exchange independent; it is designed to
       support many different key exchanges.



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   2.  Oakley [RFC2412], which describes a series of key exchanges,
       called modes, and details the services provided by each (for
       example, perfect forward secrecy for keys, identity protection,
       and authentication).

   3.  [SKEME] (Secure Key Exchange Mechanism for Internet), which
       describes a versatile key exchange technique that provides
       anonymity, reputability, and quick key refreshment.

   IKE creates an authenticated, secure tunnel between two entities and
   then negotiates the security association for IPsec.  This is
   performed in two phases.

   In Phase 1, the two unidirectional SA's establish a secure,
   authenticated channel with which to communicate.  Phase 1 has two
   distinct modes; Main Mode and Aggressive Mode.  Main Mode for Phase 1
   provides identity protection.  When identity protection is not
   needed, Aggressive Mode can be used.  The completion of Phase 1 is
   called an IKE SA.

   The following attributes are used by IKE and are negotiated as part
   of the IKE SA:

   o  Encryption algorithm.

   o  Hash algorithm.

   o  Authentication method (digital signature, public-key encryption or
      pre-shared key).

   o  Diffie-Hellman group information.

   After the attributes are negotiated, both parties must be
   authenticated to each other.  IKE supports multiple authentication
   methods.  The following mechanisms are generally implemented:

   o  Pre-shared keys: The same key is pre-installed on each host.  IKE
      peers authenticate each other by computing and sending a keyed
      hash of data that includes the pre-shared key.  If the receiving
      peer can independently create the same hash using its preshared
      key, it knows that both parties must share the same secret, and
      thus the other party is authenticated.

   o  Public key cryptography: Each party generates a pseudo-random
      number (a nonce) and encrypts it and its ID using the other
      party's public key.  The ability for each party to compute a keyed
      hash containing the other peer's nonce and ID, decrypted with the
      local private key, authenticates the parties to each other.  This



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      method does not provide nonrepudiation; either side of the
      exchange could plausibly deny that it took part in the exchange.

   o  Digital signature: Each device digitally signs a set of data and
      sends it to the other party.  This method is similar to the
      public-key cryptography approach except that it provides
      nonrepudiation.

   Note that both digital signature and public-key cryptography require
   the use of digital certificates to validate the public/private key
   mapping.  IKE allows the certificate to be accessed independently or
   by having the two devices explicitly exchange certificates as part of
   IKE.  Both parties must have a shared session key to encrypt the IKE
   tunnel.  The Diffie-Hellman protocol is used to agree on a common
   session key.

   In Phase 2 of IKE, SA's are negotiated for ESP and/or AH.  These SA's
   will be called IPsec SA's.  These IPsec SA's use a different shared
   key than that used for the IKE_SA.  The IPsec SA shared key can be
   derived by using Diffie-Hellman again or by refreshing the shared key
   derived from the original Diffie-Hellman exchange that generated the
   IKE_SA by hashing it with nonces.  Once the shared key is derived and
   additional communication parameters are negotiated, the IPsec SA's
   are established and traffic can be exchanged using the negotiated
   parameters.

3.  Document Scope

   The primary focus of this document is to establish useful performance
   testing terminology for IPsec devices that support manual keying and
   IKEv1.  We want to constrain the terminology specified in this
   document to meet the requirements of the Methodology for Benchmarking
   IPsec Devices documented test methodologies.

   The testing will be constrained to:

   o  Devices acting as IPsec gateways whose tests will pertain to both
      IPsec tunnel and transport mode.

   o  Devices acting as IPsec end-hosts whose tests will pertain to
      IPsec transport mode.

   Any testing involving interoperability and/or conformance issues,
   L2TP [RFC2661], GRE [RFC2784], MPLS VPN's [RFC2547], multicast, and
   anything that does not specifically relate to the establishment and
   tearing down of IPsec tunnels is specifically out of scope.  It is
   assumed that all relevant networking parameters that facilitate in
   the running of these tests are pre-configured (this includes at a



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   minimum ARP caches and routing tables).

4.  Definition Format

   The definition format utilized by this document is described in
   [RFC1242], Section 2.

   Term to be defined.

   Definition:

      The specific definition for the term.

   Discussion:

      A brief discussion of the term, its application, or other
      information that would build understanding.

   Issues:

      List of issues or conditions that affect this term.  This field
      can present items the may impact the term's related methodology or
      otherwise restrict its measurement procedures.

   [Measurement units:]

      Units used to record measurements of this term.  This field is
      mandatory where applicable.  This field is optional in this
      document.

   [See Also:]

      List of other terms that are relevant to the discussion of this
      term.  This field is optional in this document.


5.  Key Words to Reflect Requirements

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119.  RFC 2119
   defines the use of these key words to help make the intent of
   standards track documents as clear as possible.  While this document
   uses these keywords, this document is not a standards track document.

6.  Existing Benchmark Definitions

   It is recommended that readers consult [RFC1242], [RFC2544] and



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   [RFC2285] before making use of this document.  These and other IETF
   Benchmarking Methodology Working Group (BMWG) router and switch
   documents contain several existing terms relevant to benchmarking the
   performance of IPsec devices.  The conceptual framework established
   in these earlier RFC's will be evident in this document.

   This document also draws on existing terminology defined in other
   BMWG documents.  Examples include, but are not limited to:

             Throughput          [RFC 1242, section 3.17]
             Latency             [RFC 1242, section 3.8]
             Frame Loss Rate     [RFC 1242, section 3.6]
             Forwarding Rates    [RFC 2285, section 3.6]
             Loads               [RFC 2285, section 3.5]


7.  Definitions

7.1  IPsec

   Definition:

      IPsec or IP Security protocol suite which comprises a set of
      standards used to provide security services at the IP layer.

   Discussion:

      IPsec is a framework of protocols that offer authentication,
      integrity and encryption services to the IP and/or upper layer
      protocols.  The major components of the protocol suite are IKE,
      used for key exchanges, and IPsec protocols such as AH and ESP,
      which use the exchanged keys to protect payload traffic.

   Issues:

      N/A

   See Also:

      IPsec Device, IKE, ISAKMP, ESP, AH


7.2  ISAKMP

   Definition:






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      The Internet Security Association and Key Management Protocol,
      which provides a framework for authentication and key exchange but
      does not define them.  ISAKMP is designed to be key exchange
      independent; it is designed to support many different key
      exchanges.  ISAKMP is defined in [RFC2407].

   Discussion:

      Though ISAKMP is only a framework for the IPsec standard key
      management protocol, it is often misused and interchanged with the
      term 'IKE', which is an implementation of ISAKMP.

   Issues:

      When implementations refer to the term 'ISAKMP SA', it refers to
      an IKE Phase 1 SA.

   See Also:

      IKE, Security Association


7.3  IKE

   Definition:

      A hybrid key management protocol that provides authentication of
      the IPsec peers, negotiates IPsec SAs and establishes IPsec keys.

   Discussion:

      A hybrid protocol, defined in [RFC2409], from the following 3
      protocols:

      *  ISAKMP (Internet Security Association and Key Management
         Protocol), which provides a framework for authentication and
         key exchange but does not define them.  ISAKMP is designed to
         be key exchange independent; it is designed to support many
         different key exchanges.

      *  Oakley, which describes a series of key exchanges, called
         modes, and details the services provided by each (for example,
         perfect forward secrecy for keys, identity protection, and
         authentication).  [RFC2412]

      *  [SKEME] (Secure Key Exchange Mechanism for Internet), which
         describes a versatile key exchange technique that provides
         anonymity, reputability, and quick key refreshment.



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      Note that IKE is an optional protocol within the IPsec framework.
      IPsec SAs may also be manually configured.  Manual keying is the
      most basic mechanism to establish IPsec SAs between two IPsec
      devices.  However, it is not a scalable solution and often
      manually configured keys are not changed on a periodic basis which
      reduces the level of protection since the keys are effectively
      static and as a result are more prone to various attacks.  When
      IKE is employed as a key management protocol, the keys are
      automatically renegotiated on a user-defined basis (time and/or
      traffic volume based) as part of the IKE rekeying mechanism.

   Issues:

      During the first IPsec deployment experiences, ambiguities were
      found in the IKEv1 specification, which lead to interoperability
      problems.  To resolve these issues, IKEv1 is being updated by
      IKEv2.

   See Also:

      ISAKMP, IPsec, Security Association


7.3.1  IKE Phase 1

   Definition:

      The shared policy and key(s) used by negotiating peers to
      establish a secure authenticated "control channel" for further IKE
      communications.

   Discussion:

      The IPsec framework mandates that SPI's are used to secure payload
      traffic.  If IKE is employed all SPI information will be exchanged
      between the IPsec devices.  This has to be done in a secure
      fashion and for that reason IKE will set up a secure "control
      channel" over which it can exchange this information.

      Note that IKE is an optional protocol within the IPsec framework
      and keys can also be manually configured.

   Issues:

      In some  documents often referenced as ISAKMP SA or IKE SA.






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   See Also:

      IKE, ISAKMP


7.3.2  IKE Phase 1 Main Mode

   Definition:

      Main Mode is an instantiation of the ISAKMP Identity Protect
      Exchange, defined in [RFC2409].  Upon successful completion it
      results in the establishment of an IKE Phase 1 SA.

   Discussion:

      IKE Main Mode use 3 distinct message pairs, for a total of 6
      messages.  The first two messages negotiate policy; the next two
      represent Diffie-Hellman public values and ancillary data (e.g.
      nonces); and the last two messages authenticate the Diffie-Hellman
      Exchange.  The authentication method negotiated as part of the
      initial IKE Phase 1 influence the composition of the payloads but
      not their purpose.

   Issues:

      N/A

   See Also:

      ISAKMP, IKE, IKE Phase 1, Phase 1 Aggressive Mode


7.3.3  IKE Phase 1 Aggressive Mode

   Definition:

      Aggressive Mode is an instantiation of the ISAKMP Aggressive
      Exchange, defined in [RFC2409].  Upon successful completion it
      results in the establishment of an IKE Phase 1 SA.

   Discussion:

      IKE Aggressive Mode uses 3 messages.  The first two messages
      negotiate policy, exchange Diffie-Hellman public values and
      ancillary data necessary for the exchange, and identities.  In
      addition the second message authenticates the Responder.  The
      third message authenticates the Initiator and provides proof of
      participation in the exchange.



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   Issues:

      For IKEv1 the standard specifies that all implementations use both
      main and agressive mode, however, it is common to use only main
      mode.

   See Also:

      ISAKMP, IKE, IKE Phase 1, Phase 1 Main Mode


7.3.4  IKE Phase 2

   Definition:

      ISAKMP phase which upon successful completion establishes the
      shared keys used by the negotiating peers to set up a secure "data
      channel" for IPsec.

   Discussion:

      The main purpose of Phase 2 is to produce the key for the IPsec
      tunnel.  Phase 2 is also used to regenerate the key being used for
      IPsec (called "rekeying"), as well as for exchanging informational
      messages.

   Issues:

      In other documents also referenced as IPsec SA.

   See Also:

      IKE Phase 1, ISAKMP, IKE


7.3.5  Phase 2 Quick Mode

   Definition:

      Quick Mode is an instanciation of IKE Phase 2.  After successful
      completion it will result in one or typically two or more IPsec
      SA's

   Discussion:







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      Quick Mode is used to negotiate the SA's and keys that will be
      used to protect the user data.  Three different messages are
      exchanged, which are protected by the security parameters
      negotiated by the IKE phase 1 exchange.  An additional Diffie-
      Hellman exchange may be performed if PFS (Perfect Forward Secrecy)
      is enabled.

   Issues:

      N/A

   See Also:

      ISAKMP, IKE, IKE Phase 2


7.4  Security Association (SA)

   Definition:

      A set of policy and key(s) used to protect traffic flows that
      require authentication and/or encryption services.  It is a
      negotiation agreement between two IPsec devices, specifically the
      Initiator and Responder.

   Discussion:

      A simplex (unidirectional) logical connection that links a traffic
      flow to a set of security parameters.  All traffic traversing an
      SA is provided the same security processing and will be subjected
      to a common set of encryption and/or authentication algorithms.
      In IPsec, an SA is an Internet layer abstraction implemented
      through the use of AH or ESP as defined in [RFC2401].

   Issues:

      N/A

   See Also:

      Initiator, Responder


7.5  Selectors







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   Definition:

      A mechanism used for the classification of traffic flows that
      require authentication and/or encryption services.

   Discussion:

      The selectors are a set of fields that will be extracted from the
      network and transport layer headers that provide the ability to
      classify the traffic flow and associate it with an SA.

      After classification, a decision can be made if the traffic needs
      to be encrypted/decrypted and how this should be done depending on
      the SA linked to the traffic flow.  Simply put, selectors classify
      IP packets that require IPsec processing and those packets that
      must be passed along without any intervention of the IPsec
      framework.

      Selectors are flexible objects that can match on ranges of source
      and destination addresses and ranges of source and destination
      ports.

   Issues:

      Both sides must agree exactly on both the networks being
      protected, and they both must agree on how to describe the
      networks (range, subnet, addresses).  This is a common point of
      non-interoperability.


7.6  IPsec Device

   Definition:

      Any implementation that has the ability to process data flows
      according to the IPsec protocol suite specifications.

   Discussion:

      Implementations can be grouped by 'external' properties (e.g.
      software vs. hardware implementations) but more important is the
      subtle differences that implementations may have with relation to
      the IPsec Protocol Suite.  Not all implementations will cover all
      RFC's that encompass the IPsec Protocol Suite, but the majority
      will support a large subset of features described in the suite,
      nor will all implementations utilize all of the cryptographic
      functions listed in the RFC's.




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      In that context, any implementation, that supports basic IP layer
      security services as described in the IPsec protocol suite shall
      be called an IPsec Device.

   Issues:

      Due to the fragmented nature of the IPsec Protocol Suite RFC's, it
      is possible that IPsec implementations will not be able to
      interoperate.  Therefore it is important to know which features
      and options are implemented in the IPsec Device.

   See Also:

      IPsec


7.6.1  Initiator

   Definition:

      An IPsec device which starts the negotiation of IKE Phase 1 and
      IKE Phase 2 SAs.

   Discussion:

      When a traffic flow is offered at an IPsec device and it is
      determined that the flow must be protected, but there is no IPsec
      tunnel to send the traffic through, it is the responsibility of
      the IPsec device to start a negotiation process that will
      instantiate the IPsec tunnel.  This process will establish an IKE
      Phase 1 SA and one, or more likely, a pair IKE phase 2 SA's,
      eventually resulting in secured data transport.  The device that
      takes the action to start this negotiation process will be called
      an Initiator.

   Issues:

      IPsec devices/implementations can be both an initiator as well as
      a responder.  The distinction is useful from a test perspective.

   See Also:

      Responder, IKE, IPsec


7.6.2  Responder





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   Definition:

      An IPsec device which replies to incoming IKE Phase 1 and IKE
      Phase 2 requests and processes these messages in order to
      establish an IPsec tunnel.

   Discussion:

      When an initiator attempts to establish SA's with another IPsec
      device, this peer will need to evaluate the proposals made by the
      initiator and either accept or deny them.  In the former case, the
      traffic flow will be decrypted according to the negotiated
      parameters.  Such a device will be called a Responder.

   Issues:

      IPsec devices/implementations can usually be both an initiator as
      well as a responder.  The distinction is useful from a test
      perspective.

   See Also:

      Initiator, IKE


7.6.3  IPsec Client

   Definition:

      IPsec Devices that will only act as an Initiator.

   Discussion:

      In some situations it is not needed or prefered to have an IPsec
      device respond to an inbound IKE SA or IPsec SA request.  In the
      case of e.g. road warriors or home office scenarios the only
      property needed from the IPsec device is the ability to securely
      connect to a remote private network.  The IPsec Client will
      initiate one or more IPsec tunnels to an IPsec Server on the
      network that needs to be accessed and to provide the required
      security services.  An IPsec client will silently drop and ignore
      any inbound IPsec tunnel requests.  IPsec clients are generally
      used to connect remote users in a secure fashion over the Internet
      to a private network.







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   Issues:

      N/A

   See Also:

      IPsec device, IPsec Server, Initiator, Responder


7.6.4  IPsec Server

   Definition:

      IPsec Devices that can both act as an Initiator as well as a
      Responder.

   Discussion:

      IPsec Servers are mostly positioned at private network edges and
      provide several functions:

      *  Responds to IPsec tunnel setup request from IPsec Clients.

      *  Responds to IPsec tunnel setup request from other IPsec devices
         (Initiators).

      *  Initiate IPsec tunnels to other IPsec servers inside or outside
         the private network.

   Issues:

      IPsec Servers are also sometimes referred to as 'VPN
      Concentrators'.

   See Also:

      IPsec Device, IPsec Client, Initiator, Responder


7.7  Tunnels

   The term "tunnel" is often used in a variety of contexts.  To avoid
   any discrepancies, in this document, the following distinctions have
   been defined:

7.7.1  IPsec Tunnel





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   Definition:

      The combination of an IKE Phase 1 SA and a pair of IKE Phase 2
      SA's.

   Discussion:

      A 'Tunnel' will be defined as a single (1) Phase 1 SA and a pair
      (2) Phase 2 SA's.  This construct will allow bidirectional traffic
      to be passed between two IPsec Devices The AH and ESP protocols
      each support two modes of operation: transport mode and tunnel
      mode.  In transport mode, two hosts provide protection primarily
      for upper-layer protocols.  The cryptographic endpoints (where the
      encryption and decryption take place) are the source and
      destination of the data packet.  In IPv4, a transport mode
      security protocol header appears immediately after the IP header
      and before any higher-layer protocols (such as TCP or UDP).  In
      IPv6, the security protocol header appears after the base IP
      header and selected extension headers.  It may appear before or
      after destination options but must appear before next layer
      protocols (e.g., TCP, UDP, SCTP) In the case of AH in transport
      mode, security services are provided to selected portions of the
      IP header preceding the AH header, selected portions of extension
      headers, and selected options (contained in the IPv4 header, IPv6
      Hop-by-Hop extension header, or IPv6 Destination extension
      headers).  Any fields in these headers/extension headers which are
      modified in transit are set to 0 before applying the
      authentication algorithm.  If a field is mutable, but its value at
      the receiving IPsec peer is predictable, then that value is
      inserted into the field before applying the cryptographic
      algorithm.  In the case of ESP in transport mode, security
      services are provide only for the higher-layer protocols, not for
      the IP header or any extension headers preceding the ESP header.
      A tunnel is a vehicle for encapsulating packets inside a protocol
      that is understood at the entry and exit points of a given
      network.  These entry and exit points are defined as tunnel
      interfaces.  Both the AH and ESP protocols can be used in tunnel
      mode for data packet endpoints as well as by intermediate security
      gateways.  In tunnel mode, there is an "outer" IP header that
      specifies the IPsec processing destination, plus an "inner" IP
      header that specifies the ultimate destination for the packet.
      The source address in the outer IP header is the initiating
      cryptographic endpoint; the source address in the inner header is
      the true source address of the packet.  The security protocol
      header appears after the outer IP header and before the inner IP
      header.  If AH is employed in tunnel mode, portions of the new
      outer IP header are given protection (those same fields as for
      transport mode, described earlier in this section), as well as all



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      of the tunneled IP packet (that is, all of the inner IP header is
      protected as are the higher-layer protocols).  If ESP is employed,
      the protection is afforded only to the tunneled packet, not to the
      new outer IP header. where the traffic can benefit form the
      services offered in the IPsec framework.

   Issues:

      Since it is implied that a Phase 1 SA is used, a Tunnel will be by
      definition a dynamically negotiated secured link.  If manual
      keying is used to enable secure data transport, then this link
      will merely refered to as a pair of IKE Phase 2 SA's.

      It is very likely that more then one pair of Phase 2 SA's are
      associated with a single Phase 1 SA.  Also in this case, the
      Tunnel definition WILL NOT apply.  Instead the ratio between Phase
      1 SA's and Phase 2 SA's MUST be explictly stated.  The umbrella
      term of "IPsec Tunnel" MUST NOT be used in this context.

   See Also:

      IKE Phase 1, IKE Phase 2


7.7.2  Configured Tunnel

   Definition:

      An IPsec tunnel that is provisioned in the IPsec device's
      configuration and SADB.

   Discussion:

      Several steps are required before an IPsec Tunnel can be used to
      actually transport traffic.  The very first step is to configure
      the IPsec Tunnel in the IPsec device.  In that way packet
      classification can make a decision if it is required to start
      negotiating SA's.  At this time there are no SA's associated with
      the Tunnel and no traffic is going through the IPsec device that
      matches the Selectors, which would instantiate the IPsec Tunnel.

      A Configured Tunnel is also an IPsec Tunnel that has relinquished
      all it's SA's and is not transmitting data anymore.  To be more
      specific, when an Established or an Active Tunnel is terminated
      due to either an administrative action or an IKE event that
      deactivated the IPsec Tunnel, the IPsec Tunnel will be back in a
      configured state.




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   Issues:

      N/A

   See Also:

      Tunnel, Established Tunnel, Active Tunnel


7.7.3  Established Tunnel

   Definition:

      An IPsec Tunnel that has completed Phase 1 and Phase 2 SA
      negotiations but is otherwise idle.

   Discussion:

      A second step needed to ensure that an IPsec Tunnel can transport
      data is to complete the Phase 1 and Phase 2 negotiations.  After
      the packet classification process has asserted that a packet
      requires security services, the negotation is started to obtain
      both Phase 1 and Phase 2 SA's.  After this is completed the IPsec
      Tunnel is called 'Established'.  Note that at this time there is
      still no traffic flowing through the IPsec Tunnel.  Just enough
      packet(s) have been sent to the IPsec device that matched the
      selectors and triggered the IPsec Tunnel setup.  This may also be
      acomplished by an administrative command to connect the Tunnel, in
      which case the Tunnel is not triggered by any positive packet
      classification.

   Issues:

      In the case of manually keyed Tunnels, there is no distinction
      between a Configured Tunnel or an Established Tunnel since there
      is no negotiation required with these type of Tunnels and the
      Tunnel is Established at time of Configuration since all keying
      information is known at that point.

   See Also:

      Tunnel, Configured Tunnel, Active Tunnel


7.7.4  Active Tunnel






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   Definition:

      An IPsec Tunnel that has completed Phase 1 and Phase 2 SA
      negotiations and is forwarding data.

   Discussion:

      When an IPsec Tunnel is Established and it is transporting
      traffic, the tunnel is called 'Active'.

   Issues:

      The distinction between an Active Tunnel and Configured/
      Established Tunnel is made in the context of manual keyed Tunnels.
      In this case it would be possible to have an Established tunnel on
      an IPsec device which has no counterpart on it's corresponding
      peer.  This will lead to encrypted traffic flows which will be
      discarded on the receiving peer.  Only if both peers have an
      Established Tunnel that shows evidence of traffic transport, it
      may be called an Active Tunnel.

   See Also:

      Tunnel, Configured Tunnel, Established Tunnel


7.8  Iterated Tunnels

   Iterated Tunnels are a bundle of transport and/or tunnel mode SA's.
   The bundles are divided into two major groups :

7.8.1  Nested Tunnels

   Definition:

      An SA bundle consisting of two or more 'tunnel mode' SA's.

   Discussion:

      The process of nesting tunnels can theoretically be repeated
      multiple times (for example, tunnels can be many levels deep), but
      for all practical purposes, most implementations limit the level
      of nesting.  Nested tunnels can use a mix of AH and ESP
      encapsulated traffic.







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      [GW1] --- [GW2] ---- [IP CLOUD] ---- [GW3] --- [GW4]
        |         |                          |         |
        |         |                          |         |
        |         +----{SA1 (ESP tunnel)}----+         |
        |                                              |
        +--------------{SA2 (AH tunnel)}---------------+

      In the IP Cloud a packet would have a format like this :
      [IP{2,3}][ESP][IP{1,4}][AH][IP][PAYLOAD][ESP TRAILER][ESP AUTH]

      Nested tunnels can be deployed to provide additional security on
      already secured traffic.  A typical example of this would be that
      the inner gateways (GW2 and GW3) are securing traffic between two
      branch offices and the outer gateways (GW1 & GW4) add an
      additional layer of security between departments within those
      branch offices.

   Issues:

      N/A

   See Also:

      Transport Adjacency, IPsec Tunnel


7.8.2  Transport Adjacency

   Definition:

      An SA bundle consisting of two or more transport mode SA's.

   Discussion:

      Transport adjacency is a form of tunnel nesting.  In this case two
      or more transport mode IPsec tunnels are set side by side to
      enhance applied security properties.

      Transport adjacency can be used with a mix of AH and ESP tunnels
      although some combinations are not preferred.  If AH and ESP are
      mixed, the ESP tunnel should always encapsulate the AH tunnel.
      The reverse combination is a valid combination but doesn't make
      cryptographical sense.






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      [GW1] --- [GW2] ---- [IP CLOUD] ---- [GW3] --- [GW4]
       | |                                   |         |
       | |                                   |         |
       | +------{SA1 (ESP transport)}--------+         |
       |                                               |
       +-------------{SA2 (AH transport)}--------------+

      In the IP Cloud a packet would have a format like this :
      [IP][ESP][AH][PAYLOAD][ESP TRAILER][ESP AUTH]

   Issues:

      This is rarely used in the way it is depicted.  It is more common,
      but still not likely, that SA's are established from different
      gateways as depicted in the Nested Tunnels figure.  The packet
      format in the IP Cloud would remain unchanged.

   See Also:

      Nested Tunnels, IPsec Tunnel


7.9  Transform protocols

   Definition:

      Encryption and authentication algorithms that provide
      cryptograhical services to the IPsec Protocols.

   Discussion:

      Some algorithms run significantly slower than others.  For
      example, TripleDES encryption is one third as fast as DES
      encryption.

   Issues:

      N/A

   See Also:

      Authentication protocols, Encryption protocols







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7.9.1  Authentication Protocols

   Definition:

      Algorithms which provide data integrity and data source
      authentication.

   Discussion:

      Authentication protocols provide no confidentiality.  Commonly
      used authentication algorithms/protocols are:

           * MD5-HMAC
           * SHA-HMAC
           * AES-HMAC

   Issues:

      N/A

   See Also:

      Transform protocols, Encryption protocols


7.9.2  Encryption Protocols

   Definition:

      Algorithms which provide data confidentiality.

   Discussion:

      Encryption protocols provide no authentication.  Commonly used
      encryption algorithms/protocols are:

           * NULL encryption
           * DES-CBC
           * 3DES-CBC
           * AES-CBC

   Issues:

      Null option is a valid encryption mechanism although it reverts to
      use of IPsec back to message authenticity but only for upper layer
      protocols.





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      DES has been officially deprecated by NIST, though it is still
      mandated by the IPsec framework and is still commonly implemented
      and used due to it's speed advantage over 3DES.  AES will be the
      likely successor of 3DES due to its superior encryption and its
      single oparation nature which translates into a speed advantage.

   See Also:

      Transform protocols, Authentication protocols


7.10  IPsec Protocols

   Definition:

      A suite of protocols which provide a framework of open standards
      that provides data confidentiality, data integrity, and data
      authenticity between participating peers at the IP layer.  The
      IPsec protocol suite set of standards is documented in [RFC2401]
      through [RFC2412] and [RFC2451].

   Discussion:

      The IPsec Protocol suite is modular and forward compatible.  The
      protocols that comprise the IPsec protocol suite can be replaced
      with new versions of those protocols as the older versions become
      obsolete.  For example, IKEv2 will soon replace IKEv1.

   Issues:

      N/A

   See Also:

      AH, ESP


7.10.1  Authentication Header (AH)

   Definition:

      Provides authentication and data integrity (including replay
      protection) security services [RFC2402].

   Discussion:






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      The AH protocol supports both modes of operation; tunnel mode and
      transport mode.  If AH is employed in tunnel mode, portions of the
      outer IP header are given protection, as well as all of the
      tunneled IP packet (that is, all of the inner IP header is
      protected as are the higher-layer protocols).  In the case of AH
      in transport mode, all upper-layer information is protected, and
      all fields in the IPv4 header excluding the fields typically are
      modified in transit.

           Original IPv4 packet :
           [IP ORIG][L4 HDR][PAYLOAD]
           In transport mode :
           [IP ORIG][AH][L4 HDR][PAYLOAD]
           In tunnel mode :
           [IP NEW][AH][IP ORIG][L4 HDR][PAYLOAD]

   Issues:

      AH is rarely used to secure traffic over the Internet.

   See Also:

      Transform protocols, IPsec protocols, Encapsulated Security
      Payload


7.10.2  Encapsulated Security Payload (ESP)

   Definition:

      Provides three essential components needed for secure data
      exchange: authentication, integrity (including replay protection)
      and confidentiality as defined in [RFC2406].

   Discussion:

      The ESP protocol supports both modes of operation i.e. tunnel mode
      and transport mode.  If ESP is employed in tunnel mode, the
      protection is afforded only to the tunneled packet, not to the
      outer header.  In the case of ESP in transport mode, security
      services are provided only for the higher-layer protocols, not for
      the IP header.

           Original IPv4 packet :
           [IP ORIG][L4 HDR][PAYLOAD]
           In transport mode :
           [IP ORIG][ESP][L4 HDR][PAYLOAD][ESP TRAILER][ESP AUTH]
           In tunnel mode :



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           [IP NEW][ESP][IP ORIG][L4 HDR][PAYLOAD][ESP TRAILER][ESP AUTH]

   Issues:

      N/A

   See Also:

      Transform protocols, IPsec protocols, Authentication Header


7.11  NAT Traversal (NAT-T)

   Definition:

      The capability to support IPsec functionality in the presence of
      NAT devices.

   Discussion:

      NAT-Traversal requires some modifications to IKE as defined in
      [I-D.ietf-ipsec-nat-t-ike].  Specifically, in phase 1, it requires
      detecting if the other end supports NAT-Traversal, and detecting
      if there are one or more NAT instances along the path from host to
      host.  In IKE Quick Mode, there is a need to negotiate the use of
      UDP encapsulated IPsec packets.

      NAT-T also describes how to transmit the original source and
      destination addresses to the corresponding IPsec Device.  The
      original source and destination addresses are used in transport
      mode to incrementally update the TCP/IP checksums so that they
      will match after the NAT transform (The NAT cannot do this,
      because the TCP/IP checksum is inside the UDP encapsulated IPsec
      packet).

   Issues:

      N/A

   See Also:

      IKE, ISAKMP, IPsec Device


7.12  IP Compression






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   Definition:

      A mechanism as defined in [RFC2393] that reduces the size of the
      payload that needs to be encrypted.

   Discussion:

      IP payload compression is a protocol to reduce the size of IP
      datagrams.  This protocol will increase the overall communication
      performance between a pair of communicating hosts/gateways
      ("nodes") by compressing the datagrams, provided the nodes have
      sufficient computation power, through either CPU capacity or a
      compression coprocessor, and the communication is over slow or
      congested links.

      IP payload compression is especially useful when encryption is
      applied to IP datagrams.  Encrypting the IP datagram causes the
      data to be random in nature, rendering compression at lower
      protocol layers (e.g., PPP Compression Control Protocol [RFC1962])
      ineffective.  If both compression and encryption are required,
      compression must be applied before encryption.

   Issues:

      N/A

   See Also:

      IKE, ISAKMP, IPsec Device


7.13  Security Context

   Definition:

      A security context is a collection of security parameters that
      describe the characteristics of the path that an IPsec Tunnel will
      take, all of the IPsec Tunnel parameters and the effects it has on
      the underlying protected traffic.  Security Context encompasses
      protocol suite and security policy.

   Discussion:

      In order to fairly compare multiple IPsec devices it is imperative
      that an accurate overview is given of all security parameters that
      were used to establish the IPsec Tunnels and to secure the traffic
      between protected networks.  Security Context is not a metric; it
      is included to accurately reflect the test environment variables



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      when reporting the methodology results.  To avoid listing too much
      information when reporting metrics, we have divided the security
      context into an IKE context and an IPsec context.

      When merely discussing the behavior of traffic flows through IPsec
      devices, an IPsec context MUST be provided.  In other cases the
      scope of a discussion or report may focus on a more broad set of
      behavioral characteristics of the IPsec device, the both and IPsec
      and an IKE context MUST be provided.

      The IPsec context MUST consist of the following elements:

      *  Number of IPsec Tunnels or IKE Phase 1 / Phase 2 ratio

      *  IPsec protocol

      *  IPsec mode (tunnel or transport)

      *  Authentication protocol used by IPsec

      *  Encryption protocol used by IPsec (if applicable)

      *  IPsec SA lifetime (traffic and time based)

      The IPsec Context MAY also list:

      *  Selectors

      *  Fragmentation handling

      The IKE Context MUST consist of the following elements:

      *  Number of IKE tunnels.

      *  Authentication protocol used by IKE

      *  Encryption protocol used by IKE

      *  Key exchange mechanism (pre-shared key, certificate authority,
         etc ...)

      *  Key size (if applicable)

      *  Diffie-Hellman group

      *  IKE SA lifetime (time based)





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      *  Keepalive or DPD values as defined in [I-D.ietf-ipsec-dpd]

      *  IP Compression [RFC2393]

      *  PFS Diffie-Hellman group

      The IKE context MAY also list:

      *  Phase 1 mode (main or aggressive)

      *  Available bandwidth and latency to Certificate Authority server
         (if applicable)

   Issues:

      A Security Context will be an important element in describing the
      environment where protected traffic is traveling through.

   See Also:

      IPsec Protocols, Transform Protocols, IKE Phase 1, IKE phase 2,
      Selectors, IPsec Tunnel


8.  Framesizes

8.1  Layer3 clear framesize

   Definition:

      The total size of the unencrypted L3 PDU.

   Discussion:

      In relation to IPsec this is the size of the IP header and its
      payload.  It SHALL NOT include any encapsulations that MAY be
      applied before the PDU is processed for encryption.

      For example: 46 bytes PDU = 20 bytes IP header + 26 bytes payload.

   Measurement Units:

      Bytes

   Issues:






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      N/A

   See Also:

      Layer3 Encrypted Framesize, Layer2 Clear Framesize, Layer2
      Encrypted Framesize.


8.2  Layer3 encrypted framesize

   Definition:

      The total size of the encrypted L3 PDU.

   Discussion:

      The size of the IP packet and its payload after encapsulations MAY
      be applied and the PDU is being processed by the transform.

      For example, after a tunnel mode ESP 3DES/SHA1 transform has been
      applied an unencrypted or clear layer3 framesize of 46 bytes
      Becomes 96 bytes:

           20 bytes outer IP header (tunnel mode)
           4 bytes SPI (ESP header)
           4 bytes Sequence (ESP Header)
           8 bytes IV (IOS ESP-3DES)
           46 bytes payload
           0 bytes pad (ESP-3DES 64 bit)
           1 byte Pad length (ESP Trailer)
           1 byte Next Header (ESP Trailer)
           12 bytes ESP-HMAC SHA1 96 digest

   Measurement Units:

      Bytes

   Issues:

      N/A

   See Also:

      Layer3 Clear Framesize, Layer2 Clear Framesize, Layer2 Encrypted
      Framesize.






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8.3  Layer2 clear framesize

   Definition:

      The total size of the unencrypted L2 PDU.

   Discussion:

      This is the Layer 3 clear framesize plus all the layer2 overhead.
      In the case of Ethernet this would be 18 bytes.

      For example, a 46 byte Layer3 clear framesize packet would become
      64 Bytes after Ethernet Layer2 overhead is added:

           6 bytes destination mac address
           6 bytes source mac address
           2 bytes length/type field
           46 bytes layer3 (IP) payload
           4 bytes FCS

   Measurement Units:

      Bytes

   Issues:

      If it is not mentioned explicitly what kind of framesize is used,
      the layer2 clear framesize will be the default.

   See Also:

      Layer3 clear framesize, Layer2 encrypted framesize, Layer2
      encrypted framesize.


8.4  Layer2 encrypted framesize

   Definition:

      The total size of the encrypted L2 PDU.

   Discussion:

      This is the Layer 3 encrypted framesize plus all the layer2
      overhead.  In the case of Ethernet this would be 18 bytes.






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      For example, a 96 byte Layer3 encrypted framesize packet would
      become 114 bytes after Ethernet Layer2 overhead is added:

           6 bytes destination mac address
           6 bytes source mac address
           2 bytes length/type field
           96 bytes layer3 (IPsec) payload
           4 bytes FCS

   Measurement Units:

      Bytes

   Issues:

      N/A

   See Also:

      Layer3 Clear Framesize, Layer3 Encrypted Framesize, Layer2 Clear
      Framesize


9.  Performance Metrics

9.1  Tunnels Per Second (TPS)

   Definition:

      The measurement unit for the IPsec Tunnel Setup Rate tests.  The
      rate that IPsec Tunnels are established per second.

   Discussion:

      According to [RFC2401] two IPsec Tunnels cannot be established
      between the same gateways with the same selectors.  This is to
      prevent overlapping IPsec Tunnels.  If overlapping IPsec Tunnels
      are attempted, the error will cause the IPsec Tunnel setup time to
      take longer than if the IPsec Tunnel setup was successful.  For
      this reason, a unique pair of selector sets are required for IPsec
      Tunnel Setup Rate testing.

   Issues:

      A unique pair of selector sets are required for TPS testing.






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   See Also:

      Tunnel Setup Rate Behavior, IPsec Tunnel Setup Rate, IKE Setup
      Rate, IPsec Setup Rate


9.2  Tunnel Rekeys Per Seconds (TRPS)

   Definition:

      A metric that quantifies the number of IKE Phase 1 or Phase 2
      rekey's per seconds a DUT can correctly process.

   Discussion:

      This metric will be will be primary used with Tunnel Rekey
      behavior tests.

      TRPS will provide a metric used to see system behavior under
      stressful conditions where large volumes of tunnels are being
      rekeyed at the same time or in a short timespan.

   Issues:

      N/A

   See Also:

      Tunnel Rekey; Phase 1 Rekey Rate, Phase 2 Rekey Rate


9.3  Tunnel Attempts Per Second (TAPS)

   Definition:

      A metric that quantifies the number of successful and unsuccessful
      IPsec Tunnel establishment requests per second.

   Discussion:

      This metric can be used to measure IKE DOS Resilience behavior
      test.

      TAPS provides an important metric to validate the stability of an
      IPsec device, if stressed with valid (large number of IPsec tunnel
      establishments per seconds or TPS) or invalid (IKE DOS attacks of
      any style) tunnel establishment requests.  IPsec Tunnel setups
      offered to an IPsec devices can either fail due to lack of



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      resources in the IPsec device to proces all the requests or due to
      an IKE DOS attack (usually the former is a result of the latter).

   Issues:

      If the TAPS increases, the TPS usually decreases, due to burdening
      of the DUT with the DOS attack traffic.


10.  Test Definitions

10.1  Throughput

10.1.1  IPsec Tunnel Throughput

   Definition:

      The maximum rate through an IPsec tunnel at which none of the
      offered frames are dropped by the device under test.

   Discussion:

      The IPsec Tunnel Throughput is almost identically defined as
      Throughput in [RFC1242], section 3.17.  The only difference is
      that the throughput is measured with a traffic flow getting
      encrypted and decrypted by an IPsec device.  IPsec Tunnel
      Throughput is an end-to-end measurement.

      The metric can be represented in two variantions depending on
      where measurement is taken in the SUT.  One can look at throughput
      from a cleartext point of view i.e. find the maximum rate where
      clearpackets no longer get dropped.  This resulting rate can be
      recalculated with an encrypted framesize to represent the
      encryption throughput rate.  The latter is the preferred method of
      representation.

   Measurement Units:

      Packets per seconds (pps), Mbps

   Issues:

      N/A

   See Also:






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      IPsec Encryption Throughput, IPsec Decryption Throughput


10.1.2  IPsec Tunnel Encryption Throughput

   Definition:

      The maximum encryption rate through an IPsec tunnel at which none
      of the offered cleartext frames are dropped by the device under
      test.

   Discussion:

      Since encryption throughput is not necessarily equal to the
      decryption throughput, both of the forwarding rates must be
      measured independently.  The independent forwarding rates have to
      measured with the help of an IPsec aware test device that can
      originate and terminate IPsec and IKE tunnels.  As defined in
      [RFC1242], measurements should be taken with an assortment of
      frame sizes.

   Measurement Units:

      Packets per seconds (pps), Mbps

   Issues:

      N/A

   See Also:

      IPsec Tunnel Throughput, IPsec Tunnel Decryption Throughput


10.1.3  IPsec Tunnel Decryption Throughput

   Definition:

      The maximum decryption rate through an IPsec tunnel at which none
      of the offered encrypted frames are dropped by the device under
      test.

   Discussion:

      Since encryption throughput is not necessarily equal to the
      decryption throughput, both of the forwarding rates must be
      measured independently.




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      The independent forwarding rates have to be measured with the help
      of an IPsec aware test device that can originate and terminate
      IPsec and IKE tunnels.  As defined in [RFC1242], measurements
      should be taken with an assortment of frame sizes.

   Measurement Units:

      Packets per seconds (pps), Mbps

   Issues:

      Recommended test frame sizes will be addressed in future
      methodology document.

   See Also:

      IPsec Tunnel Throughput, IPsec Tunnel Encryption Throughput


10.2  Latency

10.2.1  IPsec Tunnel Latency

   Definition:

      Time required to propagate a cleartext frame from the input
      interface of an initiator, through an IPsec Tunnel, to the output
      interface of the responder.

   Discussion:

      The Tunnel Latency is the time interval starting when the end of
      the first bit of the cleartext frame reaches the input interface
      of the initiator and ending when the start of the first bit of the
      same cleartext frame is detected on the output interface of the
      responder.  The frame has passed through an IPsec Tunnel between
      an initiator and a responder and has been through an encryption
      and decryption cycle.

   Measurement Units:

      Time units with enough precision to reflect latency measurement.

   Issues:







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      N/A

   See Also:

      IPsec Tunnel Encryption Latency, IPsec Tunnel Decryption Latency


10.2.2  IPsec Tunnel Encryption Latency

   Definition:

      The IPsec Tunnel Encryption Latency is the time interval starting
      when the end of the first bit of the cleartext frame reaches the
      input interface, through an IPsec tunnel, and ending when the
      start of the first bit of the encrypted output frame is seen on
      the output interface.

   Discussion:

      IPsec Tunnel Encryption latency is the latency introduced when
      encrypting traffic through an IPsec tunnel.

      Like encryption/decryption throughput, it is not always the case
      that encryption latency equals the decryption latency.  Therefore
      a distinction between the two has to be made in order to get a
      more accurate view of where the latency is the most pronounced.

      The independent encryption/decryption latencies have to be
      measured with the help of an IPsec aware test device that can
      originate and terminate IPsec and IKE tunnels.  As defined in
      [RFC1242], measurements should be taken with an assortment of
      frame sizes.

   Measurement Units:

      Time units with enough precision to reflect latency measurement.

   Issues:

      N/A

   See Also:

      IPsec Tunnel Latency, IPsec Tunnel Decryption Latency







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10.2.3  IPsec Tunnel Decryption Latency

   Definition:

      The IPsec Tunnel decryption Latency is the time interval starting
      when the end of the first bit of the encrypted frame reaches the
      input interface, through an IPsec tunnel, and ending when the
      start of the first bit of the decrypted output frame is seen on
      the output interface.

   Discussion:

      IPsec Tunnel decryption latency is the latency introduced when
      decrypting traffic through an IPsec tunnel.  Like encryption/
      decryption throughput, it is not always the case that encryption
      latency equals the decryption latency.  Therefore a distinction
      between the two has to be made in order to get a more accurate
      view of where the latency is the most pronounced.

      The independent encryption/decryption latencies have to be
      measured with the help of an IPsec aware test device that can
      originate and terminate IPsec and IKE tunnels.  As defined in
      [RFC1242], measurements should be taken with an assortment of
      frame sizes.

   Measurement Units:

      Time units with enough precision to reflect latency measurement.

   Issues:

      N/A

   See Also:

      IPsec Tunnel Latency, IPsec Tunnel Encryption Latency


10.2.4  Time To First Packet

   Definition:

      The Time To First Packet (TTFP) is the time required process an
      cleartext packet when no tunnel is present.







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   Discussion:

      The TTFP addresses the issue of responsiveness of an IPsec device
      by looking how long it take to transmit a packet over a not yet
      established tunnel path.  The TTFP MUST include the time to set up
      the tunnel, triggered by the traffic flow (both phase 1 and phase
      2 setup times are included) and the time it takes to encrypt and
      decrypt the packet on a corresponding peer.  In short it is the
      tunnel setup time plus the propagation delay of the packet through
      the Tunnel.

      It must be noted that it is highly unlikely that the first packet
      of the traffic flow will be the packet that will be used to
      measure the TTFP.  There MAY be several protocol layers in the
      stack before the tunnel is formed and the traffic is forwarded,
      hence several packets COULD be lost during negotiation, for
      example, ARP and/or IKE.

   Measurement Units:

      Time units with enough precision to reflect a TTFP measurement.

   Issues:

      N/A


10.3  Frame Loss

10.3.1  IPsec Tunnel Frame Loss

   Definition:

      Percentage of cleartext frames that should have been forwarded
      through an IPsec Tunnel under steady state (constant) load but
      were dropped before encryption or after decryption.

   Discussion:

      The IPsec Tunnel Frame Loss is almost identically defined as Frame
      Loss Rate in [RFC1242], section 3.6.  The only difference is that
      the IPsec Tunnel Frame Loss Rate is measured with a traffic flow
      getting encrypted and decrypted by an IPsec device.  IPsec Tunnel
      Frame Loss Rate is an end-to-end measurement.







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   Measurement Units:

      Percent (%)

   Issues:

      N/A

   See Also:

      IPsec Tunnel Encryption Frame Loss, IPsec Tunnel Decryption Frame
      Loss


10.3.2  IPsec Tunnel Encryption Frame Loss

   Definition:

      Percentage of cleartext frames that should have been encrypted
      through an IPsec Tunnel under steady state (constant) load but
      were dropped.

   Discussion:

      DUT's will always have an inherent forwarding limitation.  This
      will be more pronounced when IPsec is employed on the DUT.  The
      moment that a Tunnel is established and traffic is offered at a
      given rate that will flow through that tunnel, there is a
      possibility that the offered traffic rate at the tunnel is too
      high to be transported through the IPsec tunnel and not all
      cleartext packets will get encrypted.  In that case, some
      percentage of the cleartext traffic will be dropped.  This drop
      percentage is called the IPsec Tunnel Encryption Frame Loss.

   Measurement Units:

      Percent (%)

   Issues:

      N/A

   See Also:

      IPsec Tunnel Frame Loss, IPsec Tunnel Decryption Frame Loss






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10.3.3  IPsec Tunnel Decryption Frame Loss

   Definition:

      Percentage of encrypted frames that should have been decrypted
      through an IPsec Tunnel under steady state (constant) load but
      were dropped.

   Discussion:

      A DUT will also have an inherent forwarding limitation when
      decrypting packets.  When established tunnel encrypted traffic is
      offered at a costant load, there might be a possibility that the
      IPsec Device that needs to decrypt the traffic will not be able to
      perfom this action on all of the packets due to limitations of the
      decryption performance.  The percentage of encrypted frames that
      would get dropped under these conditions is called the IPsec
      Tunnel Decryption Frame Loss.

   Measurement Units:

      Percent (%)

   Issues:

      N/A

   See Also:

      IPsec Tunnel Frame Loss, IPsec Tunnel Encryption Frame Loss


10.3.4  Phase 2 Rekey Frame Loss

   Definition:

      Number of frames dropped as a result of an inefficient Phase 2
      rekey.

   Discussion:

      Normal operation of an IPsec device would require that a rekey
      does not create temporary Frame Loss of a traffic stream that is
      protected by the Phase 2 SA's.  Nevertheless there can be
      situations where Frame Loss occurs during the rekey process.






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      This metric should be ideally zero but this may not be the case on
      IPsec devices where IPsec funtionality is not a core feature.

   Measurement Units:

      Number of N-octet frames

   Issues:

      N/A

   See Also:

      Phase 2 Rekey Rate


10.4  Back-to-back Frames

10.4.1  IPsec Tunnel Back-to-back Frames

   Definition:

      A burst of cleartext frames, offered at a constant load that can
      be sent through an IPsec Tunnel without losing a single cleartext
      frame after decryption.

   Discussion:

      The Tunnel Back-to-back Frames is almost identically defined as
      Back-to-back in [RFC1242], section 3.1.  The only difference is
      that the Tunnel Back-to-back Frames is measured with a traffic
      flow getting encrypted and decrypted by an IPsec device.  IPsec
      Tunnel Back-to-back Frames is an end-to-end measurement.

   Measurement Units:

      Number of N-octet frames in burst.

   Issues:

      Recommended test frame sizes will be addressed in future
      methodology document.

   See Also:







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      IPsec Tunnel Encryption Back-to-back frames, IPsec Tunnel
      Decryption Back-to-back frames


10.4.2  IPsec Tunnel Encryption Back-to-back Frames

   Definition:

      A burst of cleartext frames, offered at a constant load that can
      be sent through an IPsec Tunnel without losing a single encrypted
      frame.

   Discussion:

      Encryption back-to-back frames is the measure of the maximum burst
      size that a device can handle for encrypting traffic that it
      receives as plaintext.  Since it is not necessarily the case that
      the maximum burst size a DUT can handle for encryption is equal to
      the maximum burst size a DUT can handle for decryption, both of
      these capabilities must be measured independently.  The encryption
      back-to-back frame measurement has to be measured with the help of
      an IPsec aware test device that can decrypt the traffic to
      determine the validity of the encrypted frames.

   Measurement Units:

      Number of N-octet frames in burst.

   Issues:

      Recommended test frame sizes will be addressed in future
      methodology document.

   See Also:

      IPsec Tunnel Back-to-back frames, IPsec Tunnel Decryption Back-to-
      back frames


10.4.3  IPsec Tunnel Decryption Back-to-back Frames

   Definition:

      The number of encrypted frames, offered at a constant load, that
      can be sent through an IPsec Tunnel without losing a single
      cleartext frame.





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   Discussion:

      Decryption back-to-back frames is the measure of the maximum burst
      size that a device can handle for decrypting traffic that it
      receives as encrypted traffic.  Since it is not necessarily the
      case that the maximum burst size a DUT can handle for decryption
      is equal to the maximum burst size a DUT can handle for
      encryption, both of these capabilities must be measured
      independently.  The decryption back-to-back frame measurement has
      to be measured with the help of an IPsec aware test device that
      can determine the validity of the decrypted frames.

   Measurement Units:

      Number of N-octet frames in burst.

   Issues:

      Recommended test frame sizes will be addressed in future
      methodology document.

   See Also:

      IPsec Tunnel Back-to-back frames, IPsec Tunnel Encryption back-to-
      back frames


10.5  Tunnel Setup Rate Behavior

10.5.1  Tunnel Setup Rate

   Definition:

      The maximum number of tunnels (1 IKE SA + 2 IPsec SA's) per second
      that an IPsec device can successfully establish.

   Discussion:

      The tunnel setup rate SHOULD be measured at varying number of
      tunnels on the DUT.  Several factors may influence Tunnel Setup
      Rate, such as: TAPS rate, Background cleartext traffic load on the
      secure interface, Already established tunnels, Authentication
      method such as pre-shared keys, RSA-encryption, RSA-signature, DSS
      Key sizes used (when using RSA/DSS).







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   Measurement Units:

      Tunnels Per Second (TPS)

   Issues:

      N/A

   See Also:

      Phase 1 Setup Rate, Phase 2 Setup Rate, Tunnel Rekey


10.5.2  Phase 1 Setup Rate

   Definition:

      The maximum number of IKE tunnels (1 IKE Phase 1 SA) per second
      that an IPsec device can be observed to successfully establish.

   Discussion:

      The Phase 1 Setup Rate is a portion of the Tunnel Setup Rate.  In
      the process of establishing a Tunnel, it is interesting to know
      what the limiting factor of the IKE Finite State Machine is i.e.
      is it limited by the Phase 1 processing delays or rather by the
      Phase 2 processing delays.

   Measurement Units:

      Tunnels Per Second (TPS)

   Issues:

      N/A

   See Also:

      Tunnel Setup Rate, Phase 2 Setup Rate, Tunnel Rekey


10.5.3  Phase 2 Setup Rate

   Definition:







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      The maximum number of IPsec tunnels (2 IKE Phase 2 SA's) per
      second that a IPsec device can be observed to successfully
      establish.

   Discussion:

      The Phase 2 Setup Rate is a portion of the Tunnel Setup Rate.  For
      identical reasons why it is required to quantify the Phase 1 Setup
      Rate, it is a good practice to know the processing delays involved
      in setting up a Phase 2 SA for each direction of the protected
      traffic flow.

      Note that once you have the Tunnel Setup Rate and either the Phase
      1 or the Phase 2 Setup Rate data, you can extrapolate the
      unmeasured metric, although it is RECOMMENDED to measure all three
      metrics.

   Measurement Units:

      Tunnels Per Second (TPS)

   Issues:

      N/A

   See Also:

      Tunnel Setup Rate, Phase 1 Setup Rate, Tunnel Rekey


10.6  Tunnel Rekey

10.6.1  Phase 1 Rekey Rate

   Definition:

      The number of Phase 1 SA's that can be succesfully re-establish
      per second.

   Discussion:

      Although the Phase 1 Rekey Rate has less impact on the forwarding
      behavior of traffic that requires security services then the Phase
      2 Rekey Rate, it can pose a large burden on the CPU or network
      processor of the IPsec Device.  Due to the highly computational
      nature of a Phase 1 exchange, it may impact the stability of
      Active Tunnels in the network when the IPsec Device fails to
      properly rekey an IKE Tunnel.



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   Measurement Units:

      Rekey's per second

   Issues:

      N/A

   See Also:

      Phase 2 Rekey Rate


10.6.2  Phase 2 Rekey Rate

   Definition:

      The number of Phase 2 SA's that can be succesfully re-negotiated
      per-second.

   Discussion:

      Although many implementations will usually derive new keying
      material before the old keys expire, there may still be a period
      of time where frames get dropped before the phase 2 tunnels are
      successfully re-established.  There may also be some packetloss
      introduced when the handover of traffic is done from the expired
      SA to the newly negotiated SA.  To measure the phase 2 rekey rate,
      the measurement will require an IPsec aware test device to act as
      a responder when negotiating the new phase 2 keying material.

      The test methodology report must specify if PFS is enabled in
      reported security context.

   Measurement Units:

      Rekey's per second

   Issues:

      N/A

   See Also:

      Phase 1 Rekey Rate






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10.7  Tunnel Failover Time (TFT)

   Definition:

      Time required to recover all tunnels on a stanby IPsec device,
      after a catastrophic failure occurs on the active IPsec device.

   Discussion:

      Recovery time required to re-establish all tunnels and reroute all
      traffic on a standby node or other failsafe system after a failure
      has occurred.  Failure can include but are not limited to a
      catastrophic IPsec Device failure, a encryption engine failure,
      link outage.  The recovery time is delta between the point of
      failure and the time the first packet is seen on the last restored
      tunnel on the backup device.

   Measurement Units:

      Time units with enough precision to reflect Tunnel Failover Time.

   Issues:

      N/A


10.8  IKE DOS Resilience Rate

   Definition:

      The IKE Denial Of Service (DOS) Resilience Rate provides a rate of
      invalid or mismatching IKE tunnels setup attempts at which it is
      no longer possible to set up a valid IKE tunnel.

   Discussion:

      The IKE DOS Resilience Rate will provide a metric to how robust
      and hardened an IPsec device is against malicious attempts to set
      up a tunnel.

      IKE DOS attacks can pose themselves in various forms and do not
      necessarily have to have a malicious background.  It is sufficient
      to make a typographical error in a shared secret in an IPsec
      aggregation device to be susceptible to a large number of IKE
      attempts that need to be turned down.  Due to the intense
      computational nature of an IKE exchange every single IKE tunnel
      attempt that has to be denied will take a non-negligible time an a
      CPU in the IPsec device.



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      Depending on how many of these messages have to be processed, a
      system might end up in a state that it is only doing key exchanges
      and burdening the CPU for any other processes that might be
      running in the IPsec device.  At this point it will be no longer
      possible to process a valid IKE tunnel setup request and thus IKE
      DOS is in effect.

   Measurement Units:

      Tunnel Attempts Per Seconds (TAPS)

   Issues:

      N/A


11.  Security Considerations

   As this document is solely for the purpose of providing test
   benchmarking terminology and describes neither a protocol nor a
   protocol's implementation; there are no security considerations
   associated with this document.

12.  Acknowledgements

   The authors would like to acknowledge the following individual for
   their help and participation of the compilation and editing of this
   document: Debby Stopp, Ixia.

13.  Contributors

   The authors would like to acknowledge the following individual for
   their significant help, guidance, and contributions to this document:
   Paul Hoffman, VPNC, Sunil Kalidindi, Ixia, Brian Talbert, MCI.

14.  References

14.1  Normative References

   [RFC1242]  Bradner, S., "Benchmarking terminology for network
              interconnection devices", RFC 1242, July 1991.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2285]  Mandeville, R., "Benchmarking Terminology for LAN
              Switching Devices", RFC 2285, February 1998.




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   [RFC2393]  Shacham, A., Monsour, R., Pereira, R., and M. Thomas, "IP
              Payload Compression Protocol (IPComp)", RFC 2393,
              December 1998.

   [RFC2401]  Kent, S. and R. Atkinson, "Security Architecture for the
              Internet Protocol", RFC 2401, November 1998.

   [RFC2402]  Kent, S. and R. Atkinson, "IP Authentication Header",
              RFC 2402, November 1998.

   [RFC2403]  Madson, C. and R. Glenn, "The Use of HMAC-MD5-96 within
              ESP and AH", RFC 2403, November 1998.

   [RFC2404]  Madson, C. and R. Glenn, "The Use of HMAC-SHA-1-96 within
              ESP and AH", RFC 2404, November 1998.

   [RFC2405]  Madson, C. and N. Doraswamy, "The ESP DES-CBC Cipher
              Algorithm With Explicit IV", RFC 2405, November 1998.

   [RFC2406]  Kent, S. and R. Atkinson, "IP Encapsulating Security
              Payload (ESP)", RFC 2406, November 1998.

   [RFC2407]  Piper, D., "The Internet IP Security Domain of
              Interpretation for ISAKMP", RFC 2407, November 1998.

   [RFC2408]  Maughan, D., Schneider, M., and M. Schertler, "Internet
              Security Association and Key Management Protocol
              (ISAKMP)", RFC 2408, November 1998.

   [RFC2409]  Harkins, D. and D. Carrel, "The Internet Key Exchange
              (IKE)", RFC 2409, November 1998.

   [RFC2410]  Glenn, R. and S. Kent, "The NULL Encryption Algorithm and
              Its Use With IPsec", RFC 2410, November 1998.

   [RFC2411]  Thayer, R., Doraswamy, N., and R. Glenn, "IP Security
              Document Roadmap", RFC 2411, November 1998.

   [RFC2412]  Orman, H., "The OAKLEY Key Determination Protocol",
              RFC 2412, November 1998.

   [RFC2451]  Pereira, R. and R. Adams, "The ESP CBC-Mode Cipher
              Algorithms", RFC 2451, November 1998.

   [RFC2544]  Bradner, S. and J. McQuaid, "Benchmarking Methodology for
              Network Interconnect Devices", RFC 2544, March 1999.

   [RFC2547]  Rosen, E. and Y. Rekhter, "BGP/MPLS VPNs", RFC 2547,



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              March 1999.

   [RFC2661]  Townsley, W., Valencia, A., Rubens, A., Pall, G., Zorn,
              G., and B. Palter, "Layer Two Tunneling Protocol "L2TP"",
              RFC 2661, August 1999.

   [RFC2784]  Farinacci, D., Li, T., Hanks, S., Meyer, D., and P.
              Traina, "Generic Routing Encapsulation (GRE)", RFC 2784,
              March 2000.

   [I-D.ietf-ipsec-ikev2]
              Kaufman, C., "Internet Key Exchange (IKEv2) Protocol",
              draft-ietf-ipsec-ikev2-17 (work in progress),
              October 2004.

   [I-D.ietf-ipsec-dpd]
              Huang, G., Beaulieu, S., and D. Rochefort, "A Traffic-
              Based Method of Detecting Dead IKE Peers",
              draft-ietf-ipsec-dpd-04 (work in progress), October 2003.

   [I-D.ietf-ipsec-nat-t-ike]
              Kivinen, T., "Negotiation of NAT-Traversal in the IKE",
              draft-ietf-ipsec-nat-t-ike-08 (work in progress),
              February 2004.

   [I-D.ietf-ipsec-udp-encaps]
              Huttunen, A., "UDP Encapsulation of IPsec Packets",
              draft-ietf-ipsec-udp-encaps-09 (work in progress),
              May 2004.

   [I-D.ietf-ipsec-nat-reqts]
              Aboba, B. and W. Dixon, "IPsec-NAT Compatibility
              Requirements", draft-ietf-ipsec-nat-reqts-06 (work in
              progress), October 2003.

   [I-D.ietf-ipsec-properties]
              Krywaniuk, A., "Security Properties of the IPsec Protocol
              Suite", draft-ietf-ipsec-properties-02 (work in progress),
              July 2002.

   [FIPS.186-1.1998]
              National Institute of Standards and Technology, "Digital
              Signature Standard", FIPS PUB 186-1, December 1998,
              <http://csrc.nist.gov/fips/fips1861.pdf>.







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14.2  Informative References

   [Designing Network Security]
              Kaeo, M., "Designing Network Security",  ISBN: 1578700434,
              Published: May 07, 1999; Copyright: 1999, 1999.

   [SKEME]    Krawczyk, H., "SKEME: A Versatile Secure Key Exchange
              Mechanism for Internet",  from IEEE Proceedings of the
              1996 Symposium on Network and Distributed Systems
              Security,
              URI http://www.research.ibm.com/security/skeme.ps, 1996.


Authors' Addresses

   Michele Bustos
   IXIA
   26601 W. Agoura Rd.
   Calabasas, CA  91302
   US

   Phone: +1 (818)444-3244
   Email: mbustos@ixiacom.com


   Tim Van Herck
   Cisco Systems
   170 West Tasman Dr.
   San Jose, CA  95134-1706
   US

   Phone: +1 (408)527-2461
   Email: herckt@cisco.com


   Merike Kaeo
   Double Shot Security
   520 Washington Blvd #363
   Marina Del Rey, CA  90292
   US

   Phone: +1 (310)866-0165
   Email: kaeo@merike.com








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