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Benchmarking Working Group                                       M. Kaeo
Internet-Draft                                      Double Shot Security
Intended status: Informational                              T. Van Herck
Expires: January 29, 2010                                  Cisco Systems
                                                               M. Bustos
                                                                    IXIA
                                                           July 28, 2009


               Terminology for Benchmarking IPsec Devices
                     draft-ietf-bmwg-ipsec-term-12

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Copyright Notice

   Copyright (c) 2009 IETF Trust and the persons identified as the



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   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents in effect on the date of
   publication of this document (http://trustee.ietf.org/license-info).
   Please review these documents carefully, as they describe your rights
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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
   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.






























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Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  5
   2.  Document Scope . . . . . . . . . . . . . . . . . . . . . . . .  5
   3.  IPsec Fundamentals . . . . . . . . . . . . . . . . . . . . . .  5
     3.1.  IPsec Operation  . . . . . . . . . . . . . . . . . . . . .  7
       3.1.1.  Security Associations  . . . . . . . . . . . . . . . .  7
       3.1.2.  Key Management . . . . . . . . . . . . . . . . . . . .  8
   4.  Definition Format  . . . . . . . . . . . . . . . . . . . . . . 10
   5.  Key Words to Reflect Requirements  . . . . . . . . . . . . . . 10
   6.  Existing Benchmark Definitions . . . . . . . . . . . . . . . . 10
   7.  Definitions  . . . . . . . . . . . . . . . . . . . . . . . . . 11
     7.1.  IPsec  . . . . . . . . . . . . . . . . . . . . . . . . . . 11
     7.2.  ISAKMP . . . . . . . . . . . . . . . . . . . . . . . . . . 11
     7.3.  IKE  . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
       7.3.1.  IKE Phase 1  . . . . . . . . . . . . . . . . . . . . . 13
       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 . . . . . . . . . . . . . . . . . . . . . . . 15
       7.6.1.  Initiator  . . . . . . . . . . . . . . . . . . . . . . 16
       7.6.2.  Responder  . . . . . . . . . . . . . . . . . . . . . . 17
       7.6.3.  IPsec Client . . . . . . . . . . . . . . . . . . . . . 17
       7.6.4.  IPsec Gateway  . . . . . . . . . . . . . . . . . . . . 17
     7.7.  Tunnels  . . . . . . . . . . . . . . . . . . . . . . . . . 18
       7.7.1.  IPsec Tunnel . . . . . . . . . . . . . . . . . . . . . 18
       7.7.2.  Configured Tunnel  . . . . . . . . . . . . . . . . . . 18
       7.7.3.  Established Tunnel . . . . . . . . . . . . . . . . . . 19
       7.7.4.  Active Tunnel  . . . . . . . . . . . . . . . . . . . . 19
     7.8.  Iterated Tunnels . . . . . . . . . . . . . . . . . . . . . 20
       7.8.1.  Nested Tunnels . . . . . . . . . . . . . . . . . . . . 20
       7.8.2.  Transport Adjacency  . . . . . . . . . . . . . . . . . 21
     7.9.  Transform protocols  . . . . . . . . . . . . . . . . . . . 21
       7.9.1.  Authentication Protocols . . . . . . . . . . . . . . . 22
       7.9.2.  Encryption Protocols . . . . . . . . . . . . . . . . . 22
     7.10. IPsec Protocols  . . . . . . . . . . . . . . . . . . . . . 23
       7.10.1. Authentication Header (AH) . . . . . . . . . . . . . . 23
       7.10.2. Encapsulated Security Payload (ESP)  . . . . . . . . . 24
     7.11. NAT Traversal (NAT-T)  . . . . . . . . . . . . . . . . . . 25
     7.12. IP Compression . . . . . . . . . . . . . . . . . . . . . . 25
     7.13. Security Context . . . . . . . . . . . . . . . . . . . . . 26
   8.  Framesizes . . . . . . . . . . . . . . . . . . . . . . . . . . 28
     8.1.  Layer3 clear framesize . . . . . . . . . . . . . . . . . . 28
     8.2.  Layer3 encrypted framesize . . . . . . . . . . . . . . . . 29
   9.  Performance Metrics  . . . . . . . . . . . . . . . . . . . . . 30



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     9.1.  IPsec Tunnels Per Second (TPS) . . . . . . . . . . . . . . 30
     9.2.  Tunnel Rekeys Per Second (TRPS)  . . . . . . . . . . . . . 30
     9.3.  IPsec Tunnel Attempts Per Second (TAPS)  . . . . . . . . . 30
   10. Test Definitions . . . . . . . . . . . . . . . . . . . . . . . 31
     10.1. Capacity . . . . . . . . . . . . . . . . . . . . . . . . . 31
       10.1.1. IPsec Tunnel Capacity  . . . . . . . . . . . . . . . . 31
       10.1.2. IPsec SA Capacity  . . . . . . . . . . . . . . . . . . 31
     10.2. Throughput . . . . . . . . . . . . . . . . . . . . . . . . 32
       10.2.1. IPsec Throughput . . . . . . . . . . . . . . . . . . . 32
       10.2.2. IPsec Encryption Throughput  . . . . . . . . . . . . . 32
       10.2.3. IPsec Decryption Throughput  . . . . . . . . . . . . . 33
     10.3. Latency  . . . . . . . . . . . . . . . . . . . . . . . . . 34
       10.3.1. IPsec Latency  . . . . . . . . . . . . . . . . . . . . 34
       10.3.2. IPsec Encryption Latency . . . . . . . . . . . . . . . 34
       10.3.3. IPsec Decryption Latency . . . . . . . . . . . . . . . 35
       10.3.4. Time To First Packet . . . . . . . . . . . . . . . . . 35
     10.4. Frame Loss . . . . . . . . . . . . . . . . . . . . . . . . 36
       10.4.1. IPsec Frame Loss . . . . . . . . . . . . . . . . . . . 36
       10.4.2. IPsec Encryption Frame Loss  . . . . . . . . . . . . . 36
       10.4.3. IPsec Decryption Frame Loss  . . . . . . . . . . . . . 37
       10.4.4. IKE Phase 2 Rekey Frame Loss . . . . . . . . . . . . . 37
     10.5. Tunnel Setup Behavior  . . . . . . . . . . . . . . . . . . 38
       10.5.1. IPsec Tunnel Setup Rate  . . . . . . . . . . . . . . . 38
       10.5.2. IKE Phase 1 Setup Rate . . . . . . . . . . . . . . . . 38
       10.5.3. IKE Phase 2 Setup Rate . . . . . . . . . . . . . . . . 39
     10.6. IPsec Tunnel Rekey Behavior  . . . . . . . . . . . . . . . 39
       10.6.1. IKE Phase 1 Rekey Rate . . . . . . . . . . . . . . . . 39
       10.6.2. IKE Phase 2 Rekey Rate . . . . . . . . . . . . . . . . 40
     10.7. IPsec Tunnel Failover Time . . . . . . . . . . . . . . . . 40
     10.8. DoS Attack Resiliency  . . . . . . . . . . . . . . . . . . 41
       10.8.1. Phase 1 DoS Resiliency Rate  . . . . . . . . . . . . . 41
       10.8.2. Phase 2 Hash Mismatch DoS Resiliency Rate  . . . . . . 41
       10.8.3. Phase 2 Anti Replay Attack DoS Resiliency Rate . . . . 42
   11. Security Considerations  . . . . . . . . . . . . . . . . . . . 42
   12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 42
   13. References . . . . . . . . . . . . . . . . . . . . . . . . . . 43
     13.1. Normative References . . . . . . . . . . . . . . . . . . . 43
     13.2. Informative References . . . . . . . . . . . . . . . . . . 45
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 45












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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.  Document Scope

   The primary focus of this document is to establish useful performance
   testing terminology for IPsec devices that support manual keying and
   IKEv1.  A seperate document will be written specifically to address
   testing using the updated IKEv2 specification.  The terminology
   specified in this document is constrained to meet the requirements of
   the Methodology for Benchmarking IPsec Devices documented test
   methodologies.

   Both IPv4 and IPv6 addressing will be taken into consideration.

   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 both
      IPsec tunnel and 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
   minimum ARP caches, routing tables, neighbor tables, etc ...).


3.  IPsec Fundamentals

   IPsec is a framework of open standards that provides data
   confidentiality, data integrity, and data origin authenticity between



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   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].  At this time [RFC4301] updates
   [RFC2401] (IPsec Architecture), [RFC4302] updates [RFC2402] (AH) and
   [RFC4303] updates [RFC2406] (ESP) and [RFC4306] updates [RFC2409]
   (IKE).The reader is assumed to be familiar with these documents.

   IPsec itself defines the following:

   Authentication Header (AH): A security protocol, defined in
   [RFC4302], 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
   [RFC4303], 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
   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)




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   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 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.

3.1.  IPsec Operation

3.1.1.  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



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   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 are
   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.

3.1.2.  Key Management

   IPsec uses cryptographic keys for authentication, integrity and
   encryption services.  Both manual provisioning and automatic
   distribution of keys are 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.

   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.  In the original
   IKE specification [RFC2409], 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



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   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
      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.




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   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.


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

   See Also: (OPTIONAL)  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:  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.






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   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 SA's 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.

      Note that IKE is an optional protocol within the IPsec framework.
      IPsec SA's may also be manually configured.  Manual keying is the
      most basic mechanism to establish IPsec SA's 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.







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   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 that SPI information can also be manually configured.

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

   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.







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   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.

   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 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 instantiation of IKE Phase 2.  After
      successful completion it will result in one or typically two or
      more IPsec SA's

   Discussion:  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








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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

   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







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   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.

      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 SA's.

   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








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7.6.2.  Responder

   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.

   Issues:  N/A

   See Also:  IPsec device, IPsec Server, Initiator, Responder

7.6.4.  IPsec Gateway

   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:





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      *  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 Gateways are also sometimes referred to as 'IPsec
      Servers' or '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

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

   Discussion:  An IPsec 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 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, an IPsec
      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 be referred to as a pair of IPsec 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 IPsec
      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







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   Definition:  An IPsec tunnel or a pair of IPsec SA's in the case of
      manual keying that is provisioned in the IPsec device's
      configuration.

   Discussion:  Several steps are required before IPsec can be used to
      actually transport traffic.  The very first step is to configure
      the IPsec Tunnel (or IPsec SA's in the case of manual keying) in
      the IPsec device.  When using IKE there are no SA's associated
      with the IPsec Tunnel and no traffic is going through the IPsec
      device that matches the Selectors, which would instantiate the
      IPsec Tunnel.  When using either manual keying or IKE, a
      configured tunnel will not have a populated Security Association
      Database (SADB).

   Issues:  When using IKE, a configured tunnel will not have any SA's
      while with manual keying, the SA's will have simply been
      configured but not populated in the SADB.

   See Also:  IPsec Tunnel, Established Tunnel, Active Tunnel

7.7.3.  Established Tunnel

   Definition:  An IPsec device that has a populated SADB and is ready
      to provide security services to the appropriate traffic.

   Discussion:  When using IKE, 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 and the SADB is populated, 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 to result in a populated SADB.  In the case
      of manual keying, populating the SADB is accomplished by a
      separate administrative command.

   Issues:  N/A

   See Also:  IPsec Tunnel, Configured Tunnel, Active Tunnel

7.7.4.  Active Tunnel

   Definition:  An IPsec device that is forwarding secured data.






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   Discussion:  When a Tunnel is Established and it is transporting
      traffic that is authenticated and/or encrypted, 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:  IPsec 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.



      [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



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      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.



      [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
      cryptograhic services to the IPsec Protocols.







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   Discussion:  Some algorithms run significantly slower than others.  A
      decision for which algorithm to use is usually based on the
      tradeoff between performance and security strength.  For example,
      3DES encryption is generally slower then DES encryption.

   Issues:  N/A

   See Also:  Authentication protocols, Encryption protocols

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:  The null-encryption option is a valid encryption mechanism
      to provide an alternative to using AH.  There is no
      confidentiality protection with null-encryption.  Note also that
      when using ESP null-encryption the authentication and integrity
      services only apply for the upper layer protocols and not for the
      IP header itself.

      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
      successor of 3DES due to its superior encryption and performance



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      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 origin confidentiality, data
      integrity, and data origin authenticity between participating
      peers at the IP layer.  The original IPsec protocol suite set of
      standards is documented in [RFC2401] through [RFC2412] and
      [RFC2451].  At this time [RFC4301] updates [RFC2401] (IPsec
      Architecture), [RFC4302] updates [RFC2402] (AH) and [RFC4303]
      updates [RFC2406] (ESP)

   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 data origin authentication and data integrity
      (including replay protection) security services as defined in
      [RFC4302].

   Discussion:  The AH protocol supports two modes of operation i.e.
      tunnel mode and transport mode.

      In transport mode, AH is inserted after the IP header and before a
      next layer protocol, e.g., TCP, UDP, ICMP, etc. or before any
      other IPsec headers that have already been inserted.  In the
      context of IPv4, this calls for placing AH after the IP header
      (and any options that it contains), but before the next layer
      protocol.  In the IPv6 context, AH is viewed as an end-to-end
      payload, and thus should appear after hop-by-hop, routing, and
      fragmentation extension headers.  The destination options
      extension header(s) could appear before or after or both before
      and after the AH header depending on the semantics desired.







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      In tunnel mode, the "inner" IP header carries the ultimate (IP)
      source and destination addresses, while an "outer" IP header
      contains the addresses of the IPsec "peers," e.g., addresses of
      security gateways.  In tunnel mode, AH protects the entire inner
      IP packet, including the entire inner IP header.  The position of
      AH in tunnel mode, relative to the outer IP header, is the same as
      for AH in transport mode.

   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 data origin authentication, data integrity
      (including replayprotection) and data confidentiality as defined
      in [RFC4303].

   Discussion:  The ESP protocol supports two modes of operation i.e.
      tunnel mode and transport mode.

      In transport mode, ESP is inserted after the IP header and before
      a next layer protocol, e.g., TCP, UDP, ICMP, etc.  In the context
      of IPv4, this translates to placing ESP after the IP header (and
      any options that it contains), but before the next layer protocol.
      In the IPv6 context, ESP is viewed as an end-to-end payload, and
      thus should appear after hop-by-hop, routing, and fragmentation
      extension headers.  Destination options extension header(s) could
      appear before, after, or both before and after the ESP header
      depending on the semantics desired.  However, since ESP protects
      only fields after the ESP header, it generally will be desirable
      to place the destination options header(s) after the ESP header.

      In tunnel mode, the "inner" IP header carries the ultimate (IP)
      source and destination addresses, while an "outer" IP header
      contains the addresses of the IPsec "peers", e.g., addresses of
      security gateways.  Mixed inner and outer IP versions are allowed,
      i.e., IPv6 over IPv4 and IPv4 over IPv6.  In tunnel mode, ESP
      protects the entire inner IP packet, including the entire inner IP
      header.  The position of ESP in tunnel mode, relative to the outer
      IP header, is the same as for ESP in transport mode.

   Issues:  N/A







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   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 [RFC3947].  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

   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.





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   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 or
      manually created SA's and to secure the traffic between protected
      networks.  Security Context is not a metric.  It is included to
      accurately reflect the test environment variables when reporting
      the methodology results.  To avoid listing too much information
      when reporting metrics, the Security Context is divided 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, in which case both
      an IPsec and an IKE context MUST be provided.

      The IPsec context MUST consist of the following elements:

      *  Manual Keyed Tunnels versus IKE negotiated Tunnels

      *  Number of IPsec Tunnels or IPsec SA's

      *  IPsec protocol (AH or ESP)

      *  IPsec protocol mode (tunnel or transport)

      *  Authentication algorithm used by AH/ESP

      *  Encryption algoritm used ESP (if applicable)

      *  IPsec SA lifetime (traffic and time based)

      *  Anti Replay Window Size (Assumed to be 64 packets if not
         specified)





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      The IPsec Context MAY also list:

      *  Selectors

      *  Fragmentation handling (assumed to be post-encryption when not
         mentioned)

      *  Path MTU Discovery (PMTUD) (assumed disabled when not
         mentioned)

      The IKE Context MUST consist of the following elements:

      *  Number of IPsec Tunnels.

         +  IKE Phase 1 SA to IKE Phase 2 SA ratio (if applicable)

         +  IKE Phase 1 parameters

            -  Authentication algorithm

            -  Encryption algorithm

            -  DH-Group

            -  SA lifetime (traffic and time based)

            -  Authentication mechanism (pre-shared key, RSA-sig,
               certificate, etc)

         +  IKE Phase 2 parameters

            -  IPsec protocol (part of IPsec context)

            -  IPsec protocol mode (part of IPsec context)

            -  Authentication algorithm (part of IPsec context)

            -  Encryption algorithm (part of IPsec context)

            -  DH-Group

            -  PFS Group used

            -  SA Lifetime (part of IPsec context)

      *  Use of IKE Keepalive or Dead Peer Detection (DPD), as defined
         in [RFC3706], and its interval and retry values (assumed
         disabled when not mentioned).



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      *  IP Compression [RFC2393]

      The IKE context MUST also list:

      *  Phase 1 mode (main or aggressive)

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

      *  Indication of NAT traversal

   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.

      IPv4 example: For a 64 byte Ethernet packet, the IPv4 Layer3 PDU
      is calculated as:

       L3 PDU = 64 bytes - L2 Ethernet Header (18 bytes)
              = 46 bytes PDU
              = 20 bytes IPv4 header + 26 bytes payload.

      IPv6 example: For a 64 byte Ethernet packet, the IPv6 Layer3 PDU
      is calculated as:

       L3 PDU = 64 bytes - L2 Ethernet Header (18 bytes)
              = 46 bytes PDU
              = 40 bytes IPv6 base header + 6 bytes payload.

   Measurement Units:  Bytes







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   Issues:  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, when using a tunnel mode ESP 3DES/SHA1 transform to
      protect an unencrypted IPv4 L3 PDU of 46 bytes, the L3 encrypted
      framesize becomes 96 bytes:

           20 bytes outer IPv4 header (Tunnel mode)
           4 bytes SPI (ESP Header)
           4 bytes Sequence (ESP Header)
           8 bytes IV (IOS ESP-3DES)
           46 bytes payload (Original IPv4 L3 PDU)
           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

      For the same example but protecting an unencrypted IPv6 L3 PDU of
      46 bytes, the L3 framesize becomes 116 bytes:

           40 bytes outer IPv6 header (Tunnel mode)
           4 bytes SPI (ESP Extension Header)
           4 bytes Sequence (ESP Extension Header)
           8 bytes IV (IOS ESP-3DES)
           46 bytes payload (Original IPv6 L3 PDU)
           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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9.  Performance Metrics

9.1.  IPsec Tunnels Per Second (TPS)

   Definition:  The measurement unit for the IPsec Tunnel Setup Rate
      tests.  The rate at which 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 (and non-overlapping).  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.

   See Also:  IPsec Tunnel Setup Rate Behavior, IPsec Tunnel Setup Rate,
      IKE Setup Rate, IPsec Setup Rate

9.2.  Tunnel Rekeys Per Second (TRPS)

   Definition:  A metric that quantifies the number of IKE Phase 1 or
      Phase 2 rekeys per second 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 SA's are being rekeyed
      at the same time or in a short timespan.

   Issues:  N/A

   See Also:  Tunnel Rekey Behavior, Phase 1 Rekey Rate, Phase 2 Rekey
      Rate

9.3.  IPsec 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.






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      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
      resources in the IPsec device to process 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.

   See Also:  N/A


10.  Test Definitions

10.1.  Capacity

10.1.1.  IPsec Tunnel Capacity

   Definition:  The maximum number of Active IPsec Tunnels that can be
      sustained on an IPsec Device.

   Discussion:  This metric will represent the quantity of IPsec Tunnels
      that can be established on an IPsec Device that can forward
      traffic i.e.  Active Tunnels.  It will be a measure that indicates
      how many remote peers an IPsec Device can establish a secure
      connection with.  For IPsec Tunnel Capacity, each IPsec SA is
      associated with exactly 1 IKE SA.

   Measurement Units:  IPsec Tunnels

   Issues:  N/A

   See Also:  IPsec SA Capacity

10.1.2.  IPsec SA Capacity

   Definition:  The maximum number of IPsec SA's that can be sustained
      on an IPsec Device.

   Discussion:  This metric will represent the quantity of traffic flows
      a given IPsec Device can protect.  In contrast with the IPsec
      Tunnel Capacity, the emphasis for this test lies on the number of
      IPsec SA's that can be established in the worst case scenario.
      This scenario would be a case where 1 IKE SA is used to negotiate
      multiple IPsec SA's.  It is the maximum number of Active Tunnels



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      that can be sustained by an IPsec Device where only 1 IKE SA is
      used to exchange keying material.

   Measurement Units:  IPsec SA's

   Issues:  N/A

   See Also:  IPsec Tunnel Capacity

10.2.  Throughput

10.2.1.  IPsec Throughput

   Definition:  The maximum rate through an Active Tunnel at which none
      of the offered frames are dropped by the device under test.

   Discussion:  The IPsec 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 Throughput is
      an end-to-end measurement.

   Measurement Units:  Packets per seconds (pps)

   Issues:  N/A

   See Also:  IPsec Encryption Throughput, IPsec Decryption Throughput

10.2.2.  IPsec Encryption Throughput

   Definition:  The maximum encryption rate through an Active 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 SA.  As defined in
      [RFC1242], measurements should be taken with an assortment of
      frame sizes.

   Measurement Units:  Packets per seconds (pps)

   Issues:  In some cases packets are offered to an IPsec Device that
      have a framesize that is larger then the MTU of the ingress
      interface of the IPsec Tunnel that is transporting the packet.  In
      this case fragmentation will be required before IPsec services are



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      applied.

      In other cases, the packet is of a size very close to the MTU of
      the egress interface of the IPsec Tunnel.  Here, the mere addition
      of the IPsec header will create enough overhead to make the IPsec
      packet larger then the MTU of the egress interface.  In such
      instance, the original payload packet must be fragmented either
      before or after the IPsec overhead is applied.

      Note that the two aforementioned scenarios can happen
      simultaniously on a single packet, creating multiple small
      fragments.

      When measuring the IPsec Encryption Throughput, one has to
      consider that when probing with packets of a size near MTU's
      associated with the IPsec Tunnel, fragmentation may accor and the
      decrypting IPsec Device (either a tester or a corresponding IPsec
      peer) has to reassemble the IPsec and/or payload fragments to
      validate its content.

      The end points (i.e. hosts, subnets) should NOT see any fragments
      at ANY time.  Only on the IPsec link, fragments MAY occur.

   See Also:  IPsec Throughput, IPsec Decryption Throughput

10.2.3.  IPsec Decryption Throughput

   Definition:  The maximum decryption rate through an Active 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.

      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 SA.  As defined in [RFC1242], measurements should be
      taken with an assortment of frame sizes.

   Measurement Units:  Packets per seconds (pps)

   Issues:  When measuring the IPsec Decryption Throughput, one has to
      consider that it is likely that the encrypting IPsec Device has to
      fragment certain packets that have a frame size near MTU's
      associated with the IPsec Tunnel.





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      The decrypting IPsec Device has to reassemble the IPsec and/or
      payload fragments to validate its content.

      The end points (i.e. hosts, subnets) should NOT see any fragments
      at ANY time.  Only on the IPsec link, fragments MAY occur.

   See Also:  IPsec Throughput, IPsec Encryption Throughput

10.3.  Latency

10.3.1.  IPsec Latency

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

   Discussion:  The IPsec 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
      Active 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:  N/A

   See Also:  IPsec Encryption Latency, IPsec Decryption Latency

10.3.2.  IPsec Encryption Latency

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

   Discussion:  IPsec 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.





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      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 SA.  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 Latency, IPsec Decryption Latency

10.3.3.  IPsec Decryption Latency

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

   Discussion:  IPsec Decryption Latency is the latency introduced when
      decrypting traffic through an Active 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 SA's.  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 Latency, IPsec Encryption Latency

10.3.4.  Time To First Packet

   Definition:  The Time To First Packet (TTFP) is the time required to
      process a cleartext packet from a traffic stream that requires
      encryption services when no IPsec Tunnel is present.





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   Discussion:  The Time To First Packet addresses the issue of
      responsiveness of an IPsec device by looking how long it takes to
      transmit a packet over Configured Tunnel.  The Time To First
      Packet MUST include the time to set up the established tunnel,
      triggered by the traffic flow (both phase 1 and phase 2 setup
      times SHALL be included) and the time it takes to encrypt and
      decrypt the packet on a corresponding peer.  In short it is the
      IPsec Tunnel setup time plus the propagation delay of the packet
      through the Active 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:  Only relevant when using IKE for tunnel negotiation.

10.4.  Frame Loss

10.4.1.  IPsec Frame Loss

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

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

   Measurement Units:  Percent (%)

   Issues:  N/A

   See Also:  IPsec Encryption Frame Loss, IPsec Decryption Frame Loss

10.4.2.  IPsec Encryption Frame Loss

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




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   Discussion:  A DUT will always have an inherent forwarding
      limitation.  This will be more pronounced when IPsec is employed
      on the DUT.  There is a possibility that the offered traffic rate
      at the Active Tunnel is too high to be transported through the
      Active 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 Encryption
      Frame Loss.

   Measurement Units:  Percent (%)

   Issues:  N/A

   See Also:  IPsec Frame Loss, IPsec Decryption Frame Loss

10.4.3.  IPsec Decryption Frame Loss

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

   Discussion:  A DUT will also have an inherent forwarding limitation
      when decrypting packets.  When Active 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
      Decryption Frame Loss.

   Measurement Units:  Percent (%)

   Issues:  N/A

   See Also:  IPsec Frame Loss, IPsec Encryption Frame Loss

10.4.4.  IKE Phase 2 Rekey Frame Loss

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

   Discussion:  Normal operation of an IPsec Device would require that a
      rekey does not create temporary IPsec Frame Loss of a traffic
      stream that is protected by the IKE Phase 2 SA's (i.e.  IPsec
      SA's).  Nevertheless there can be situations where IPsec Frame
      Loss occurs during this 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:  IKE Phase 2 Rekey Rate

10.5.  Tunnel Setup Behavior

10.5.1.  IPsec Tunnel Setup Rate

   Definition:  The maximum number of IPsec Tunnels per second that an
      IPsec Device can successfully establish.

   Discussion:  The Tunnel Setup Rate SHOULD be measured at varying
      number of IPsec Tunnels (1 Phase 1 SA and 2 Phase 2 SA's) on the
      DUT.  Several factors may influence Tunnel Setup Rate, such as:
      TAPS rate, Background cleartext traffic load on the secure
      interface, Already established IPsec Tunnels, Authentication
      method such as pre-shared keys, RSA-encryption, RSA-signature, DSS
      Key sizes used (when using RSA/DSS).

      The Tunnel Setup Rate is an important factor to understand when
      designing networks using stateless failover of IPsec tunnels to a
      standby chassis.  At the same time it can be important to set
      Connection and Admission control paramters in an IPsec device to
      prevent overloading the IPsec Device.

   Measurement Units:  Tunnels Per Second (TPS)

   Issues:  N/A

   See Also:  IKE Phase 1 Setup Rate, IKE Phase 2 Setup Rate, IPsec
      Tunnel Rekey Behavior

10.5.2.  IKE Phase 1 Setup Rate

   Definition:  The maximum number of sucessful IKE Phase 1 SA's per
      second that an IPsec Device can establish.

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




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   Measurement Units:  Tunnels Per Second (TPS)

   Issues:  N/A

   See Also:  IPsec Tunnel Setup Rate, IKE Phase 2 Setup Rate, IPsec
      Tunnel Rekey Behavior

10.5.3.  IKE Phase 2 Setup Rate

   Definition:  The maximum number of successful IKE Phase 2 SA's per
      second that an IPsec Device can Only relevant when using IKE
      establish.

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

      IKE Phase 2 Setup Rates will ALWAYS be measured for multiples of
      two IKE Phase 2 SA's.

      Note that once you have the IPsec Tunnel Setup Rate and either the
      IKE Phase 1 or the IKE Phase 2 Setup Rate data, you can
      extrapolate the unmeasured metric.  It is however highly
      RECOMMENDED to measure all three metrics since the IKE and IPsec
      SA establishment are two distinct and decoupled phases in the
      establishment of a Tunnel.

   Measurement Units:  Tunnels Per Second (TPS)

   Issues:  N/A

   See Also:  IPsec Tunnel Setup Rate, IKE Phase 1 Setup Rate, IPsec
      Tunnel Rekey Behavior

10.6.  IPsec Tunnel Rekey Behavior

10.6.1.  IKE Phase 1 Rekey Rate

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

   Discussion:  Although the IKE Phase 1 Rekey Rate has less impact on
      the forwarding behavior of traffic that requires security services
      then the IKE 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



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      stability of Active Tunnels in the network when the IPsec Device
      fails to properly rekey an IKE Phase 1 SA.

   Measurement Units:  Tunnel Rekeys per second (TRPS)

   Issues:  N/A

   See Also:  IKE Phase 2 Rekey Rate

10.6.2.  IKE Phase 2 Rekey Rate

   Definition:  The number of IKE 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 IKE Phase 2
      tunnels are successfully re-established.  There may also be some
      packet loss introduced when the handover of traffic is done from
      the expired IPsec SA's to the newly negotiated IPsec SA's.  To
      measure the IKE Phase 2 rekey rate, the measurement will require
      an IPsec aware test device to act as a responder when negotiating
      the new IKE Phase 2 keying material.

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

   Measurement Units:  Tunnel Rekeys per second (TRPS)

   Issues:  N/A

   See Also:  IKE Phase 1 Rekey Rate

10.7.  IPsec Tunnel Failover Time

   Definition:  Time required to recover all IPsec Tunnels on a stanby
      IPsec Device, after a catastrophic failure occurs on the active
      IPsec Device.

   Discussion:  Recovery time required to re-establish or to engage all
      IPsec Tunnels and reroute all traffic on a standby node or other
      failsafe system after a failure has occurred in the original
      active DUT/SUT.  Failure can include, but are not limited to, a
      catastrophic IPsec Device failure, a encryption engine failure,
      protocol failures and link outages.  The recovery time is delta
      between the point of failure and the time the first packet is seen
      on the last restored IPsec Tunnel on the backup device.




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   Measurement Units:  Time units with enough precision to reflect IPsec
      Tunnel Failover Time.

   Issues:  N/A

10.8.  DoS Attack Resiliency

10.8.1.  Phase 1 DoS Resiliency Rate

   Definition:  The Phase 1 Denial of Service (DoS) Resilience Rate
      quantifies the rate of invalid or malicious IKE tunnels that can
      be directed at a DUT before the Responder ignores or rejects valid
      tunnel attempts.

   Discussion:  Phase 1 DoS attacks can present 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 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 non-negligible CPU cycles
      in the IPsec Device.

      Depending on the quantity of these messages that have to be
      processed, a system might end up in a state that the burden on
      system resource performing key exchanges is high enough that all
      resources are consumed by this process.  At this point it will be
      no longer possible to process a valid IKE tunnel setup request and
      thus a Phase 1 DoS Attack is in effect.

      The scope of the attack profile for this test will include
      mismatched pre-shared keys as well as invalid digital
      certificates.

   Measurement Units:  Percentage of FailedTunnel Attempts Per Seconds
      (TAPS)

   Issues:  N/A

10.8.2.  Phase 2 Hash Mismatch DoS Resiliency Rate

   Definition:  The Phase 2 Hash Mismatch Denial of Service (DoS)
      Resilience Rate quantifies the rate of invalid ESP/AH packets that
      a DUT can drop without affecting the traffic flow of valid ESP/AH
      packets.






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   Discussion:  Phase 2 DoS attacks can present themselves in various
      forms and do not necessarily have to have a malicious background,
      but usually are.  Typical are cases where there is a true
      malicious intent in the ESP/AH traffic flow by e.g. having an
      invalid hash in the IPsec data packets.

      Depending on the quantity of these packets that have to be
      processed, a system might end up in a state that the burden on the
      IPsec Device becomes large enough that it will impact valid
      traffic flows.  At this point it will be no longer possible to
      forward valid IPsec payload without packetloss and thus a Phase 2
      DoS Attack is in effect.

   Measurement Units:  Packets per seconds (pps)

   Issues:  N/A

10.8.3.  Phase 2 Anti Replay Attack DoS Resiliency Rate

   Definition:  The Phase 2 Anti Replay Attack Denial of Service (DoS)
      Resilience Rate quantifies the rate of replayed ESP/AH packets
      that a DUT can drop without affecting the traffic flow of valid
      ESP/AH packets.

   Discussion:  Anti Replay protection is a cornerstone feature of the
      IPsec framework and can be found in both the AH as well as the ESP
      protocol.  To better understand what the impact is of a replay
      attack on an IPsec device, a valid IPsec stream will be replayed
      and each packet of the stream will appear twice on the wire at
      different times where the second instance will be outside of the
      Anti Replay Window.

   Measurement Units:  Replayed Packets per seconds (pps)

   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 individuals for



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   their participation of the compilation and editing of this document
   and guidance: Debby Stopp, Paul Hoffman, Sunil Kalidindi, Brian
   Talbert, Yaron Sheffer and Al Morton.


13.  References

13.1.  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.

   [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



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              (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,
              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.

   [RFC3947]  Kivinen, T., Swander, B., Huttunen, A., and V. Volpe,
              "Negotiation of NAT-Traversal in the IKE", RFC 3947,
              January 2005.

   [RFC4301]  Kent, S. and K. Seo, "Security Architecture for the
              Internet Protocol", RFC 4301, December 2005.

   [RFC4302]  Kent, S., "IP Authentication Header", RFC 4302,
              December 2005.

   [RFC4303]  Kent, S., "IP Encapsulating Security Payload (ESP)",
              RFC 4303, December 2005.

   [RFC4306]  Kaufman, C., "Internet Key Exchange (IKEv2) Protocol",
              RFC 4306, December 2005.

   [RFC3706]  Huang, G., Beaulieu, S., and D. Rochefort, "A Traffic-
              Based Method of Detecting Dead Internet Key Exchange (IKE)
              Peers", RFC 3706, February 2004.




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   [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>.

13.2.  Informative References

   [Designing Network Security]
              Kaeo, M., "Designing Network Security",  ISBN: 1587051176,
              Published: November, 2004.

   [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

   Merike Kaeo
   Double Shot Security
   3518 Fremont Ave N #363
   Seattle, WA  98103
   USA

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


   Tim Van Herck
   Cisco Systems
   170 West Tasman Drive
   San Jose, CA  95134-1706
   USA

   Phone: +1(408)853-2284
   Email: herckt@cisco.com








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

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











































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