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Versions: (draft-saucez-lisp-impact) 00 01 02 03 04 05 RFC 7834

Network Working Group                                          D. Saucez
Internet-Draft                                                     INRIA
Intended status: Informational                                L. Iannone
Expires: May 23, 2016                                  Telecom ParisTech
                                                             A. Cabellos
                                                                F. Coras
                                                 Technical University of
                                                               Catalonia
                                                       November 20, 2015


                              LISP Impact
                     draft-ietf-lisp-impact-05.txt

Abstract

   The Locator/Identifier Separation Protocol (LISP) aims at improving
   the Internet routing scalability properties by leveraging on three
   principles: address role separation, encapsulation, and mapping.  In
   this document, based on implementation work, deployment experiences,
   and theoretical studies, we discuss the impact that the deployment of
   LISP can have on both the routing infrastructure and the end-user.

Status of this Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
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   This Internet-Draft will expire on May 23, 2016.

Copyright Notice

   Copyright (c) 2015 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of



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   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
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   include Simplified BSD License text as described in Section 4.e of
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Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  LISP in a nutshell . . . . . . . . . . . . . . . . . . . . . .  3
   3.  LISP for scaling the Internet Routing Architecture . . . . . .  4
   4.  Beyond scaling the Internet Routing Architecture . . . . . . .  6
     4.1.  Traffic engineering  . . . . . . . . . . . . . . . . . . .  7
     4.2.  LISP for IPv6 Co-existence . . . . . . . . . . . . . . . .  8
     4.3.  Inter-domain multicast . . . . . . . . . . . . . . . . . .  9
   5.  Impact of LISP on operations and business models . . . . . . .  9
     5.1.  Impact on non-LISP traffic and sites . . . . . . . . . . . 10
     5.2.  Impact on LISP traffic and sites . . . . . . . . . . . . . 10
   6.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 12
   7.  Security Considerations  . . . . . . . . . . . . . . . . . . . 12
   8.  Acknowledgments  . . . . . . . . . . . . . . . . . . . . . . . 13
   9.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 13
     9.1.  Normative References . . . . . . . . . . . . . . . . . . . 13
     9.2.  Informative References . . . . . . . . . . . . . . . . . . 14
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 17
























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1.  Introduction

   The Locator/Identifier Separation Protocol (LISP) relies on three
   principles to improve the scalability properties of Internet routing:
   address role separation, encapsulation, and mapping.  When invented,
   LISP was targeted at solving the Internet routing scaling problem
   ([RFC4984]).  There have now been years of implementations and
   experiments examining the impact and open questions of using LISP to
   improve inter-domain routing scalability.  Experience has shown that
   because LISP utilizes mapping and encapsulation technologies, it can
   be deployed and used for purposes that go beyond routing scalability.
   For example, LISP provides a mean for a LISP site to precisely
   control its inter-domain outgoing and incoming traffic, with the
   possibility to apply different policies to different domains
   exchanging traffic with it.  LISP can also be used to ease the
   transition from IPv4 to IPv6 as it allows the transport of IPv4 over
   IPv6 or IPv6 over IPv4.  Furthermore, LISP also supports inter-domain
   multicast.

   Leveraging on implementation and deployment experience, as well as
   research work, this document describes, at a high level, the impacts
   and open questions still seen in LISP.  This information is
   particularly useful for considering future approaches and to support
   further experimentation to clarify some large open questions (e.g.
   around the operations).  LISP utilizes a tunnel-based data plane and
   a distributed control plane.  LISP requires some new functionalities,
   such as reachability mechanisms.  Being more than a simple
   encapsulation technology and as a new technology, until even more
   deployment experience is gained, some open questions, related to LISP
   deployment and operations, remain.  As an encapsulation technology,
   there may be concerns on reduced Maximum Transmission Unit (MTU) size
   in some deployments.  An important impact of LISP is on network
   operations related to resiliency and troubleshooting.  As LISP relies
   on cached mappings and on encapsulation, resiliency during failures
   and troubleshooting may be more difficult.  Also, the use of
   encapsulation may make failure detection and recovery slower and it
   will require more coordination than with a single, non-encapsulated,
   routing domain solution.


2.  LISP in a nutshell

   The Locator/Identifier Separation Protocol (LISP) relies on three
   principles: address role separation, encapsulation, and mapping.

   The address space is divided into two sets that have different
   semantic meanings: the Routing Locators (RLOCs) and the Endpoint
   Identifiers (EIDs).  RLOCs are addresses typically assigned from the



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   Provider Aggregatable (PA) address space.  The EIDs are attributed to
   the nodes in the edge networks, by a block of contiguous addresses,
   which are typically Provider Independent (PI).  To limit the
   scalability problem, LISP only requires the PA routes towards the
   RLOCs to be announced in the Provider infrastructure.  Whereas, for
   non-LISP deployments the EIDs need as well to be propagated.

   LISP routers are used at the boundary between the EID and the RLOC
   spaces.  Routers used to exit the EID space (towards the Provider
   domain) are called Ingress Tunnel Router (ITRs) and those used to
   enter the EID space (from the Provider domain) are called the Egress
   Tunnel Routers (ETRs).  When a host sends a packet to a remote
   destination, it sends it as in the non-LISP Internet.  The packet
   arrives at the border of its site at an ITR.  Because EIDs are not
   routable on the Internet, the packet is encapsulated with the source
   address set to the ITR RLOC and the destination address set to the
   ETR RLOC.  The encapsulated packet is then forwarded in the Provider
   domain until it reaches the selected ETR.  The ETR de-encapsulates
   the packet and forwards it to its final destination.  The acronym xTR
   for Ingress/Egress tunnel router is used for a router playing these
   two roles.

   The correspondence between EIDs and RLOCs is given by the mappings.
   When an ITR needs to find ETR RLOCs that serve an EID, it queries a
   mapping system.  With the LISP Canonical Address Format (LCAF)
   [I-D.ietf-lisp-lcaf], LISP is not restricted to the Internet Protocol
   for the EID addresses.  With LCAF, any address type can be used as
   EID (the address is only the key for the mapping lookup).  LISP can
   transport, for example, Ethernet frames over the Internet.

   An introduction to LISP can be found in [RFC7215].  The LISP
   specifications are given in [RFC6830], [RFC6833],
   [I-D.ietf-lisp-ddt], [RFC6836], [RFC6832], [RFC6834].


3.  LISP for scaling the Internet Routing Architecture

   The original goal of LISP was to improve the scalability properties
   of the Internet routing architecture.  LISP utilizes traffic
   engineering and stub AS prefixes (not announced anymore in the DFZ),
   so that routing tables are smaller and more stable (i.e., they
   experience less churn).  Furthermore, at the edge of the network,
   information necessary to forward packets (i.e., the mappings) is
   obtained on demand using a pull model (whereas the current Internet
   BGP model uses a push model).  Therefore, the scalability of edge
   networks is less dependent on the Internet's size and more related to
   its traffic matrix.  This scaling improvement has been proven by
   several studies (see below).  The research studies cited hereafter



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   are based on the following assumptions:

   o  EID-to-RLOC mappings follow the same prefix size as the current
      BGP routing infrastructure (current PI addresses only);

   o  EIDs are used only at the stub ASes, not in the transit ASes;

   o  the RLOCs of an EID prefix are deployed at the edge between the
      stubs owning the EID prefix and the providers, allocating the
      RLOCs in a Provider Aggregetable (PA) mode.

   The above assumptions are inline with [RFC7215] and current LISP
   deployments.  It is recognized these assumptions may change in the
   longer term.  [KIF13] and [CDLC] explore different EDI prefix space
   sizes, and still show results that are consistent and equivalent to
   the above assumptions.

   Quoitin et al.  [QIdLB07] show that the separation between locator
   and identifier roles at the network level improves the routing
   scalability by reducing the Routing Information Base (RIB) size (up
   to one order of magnitude) and increases path diversity and thus the
   traffic engineering capabilities.  [IB07] and [KIF13] show, based on
   real Internet traffic traces, that the number of mapping entries that
   must be handled by an ITR of a network with up to 20,000 users is
   limited to few tens of thousands; that the signaling traffic (i.e.,
   Map-Request/Map-Reply packets) is in the same order of magnitude
   similar to DNS requests/reply traffic; and that the encapsulation
   overhead, while not negligible, is very limited (in the order of few
   percentage points of the total traffic volume).

   Previous studies consider the case of a timer-based cache eviction
   policy (i.e., mappings are deleted from the cache upon timeout),
   while [CDLC] has a more general approach based on the Least Recently
   Used (LRU) eviction policy, proposing an analytic model for the EID-
   to-RLOC cache size when prefix-level traffic has a stationary
   generating process.  The model shows that miss rate can be accurately
   predicted from the EID-to-RLOC cache size and a small set of easily
   measurable traffic parameters.  The model was validated using four
   one-day-long packet traces collected at egress points of a campus
   network and an academic exchange point considering EID-prefixes as
   being of the same size as BGP prefixes.  Consequently, operators can
   provision the EID-to-RLOC cache of their ITRs according to the miss
   rate they want to achieve for their given traffic.

   Results in [CDLC] indicate that for a given target miss-ratio, the
   size of the cache depends only on the parameters of the popularity
   distribution, being independent of the number of users (the size of
   the LISP site) and the number of destinations (the size of the EID-



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   prefix space).  Assuming that the popularity distribution remains
   constant, this means that as the number of users and the number of
   destinations grow, the cache size needed to obtain a given miss rate
   remains constant O(1).

   LISP usually populates its EID-to-RLOC cache in a pull mode which
   means that mappings are retrieved on demand by the ITR.  The main
   advantage of this mode is that the EID-to-RLOC cache size only
   depends on the traffic characteristics at the ITR and is independent
   of the size of the Provider domain.  This benefit comes at the cost
   of some delay to transmit the packets that do not hit an entry in the
   cache (for which a mapping has to be learned).  This delay is bound
   by the time necessary to retrieve the mapping from the mapping
   system.  Moreover, similarly to a push model (e.g., BGP), the pull
   model induces signaling messages that correspond to the retrieval of
   mappings upon cache miss.  The difference being that the signaling
   load only depends on the traffic at the ITR and is not triggered by
   external events such as in BGP.  [CDLC] shows that the miss rate is a
   function of the EID-to-RLOC cache size and traffic generation process
   and [CDLC], [SDIB08], and [SDIB08] show from traffic traces that, in
   practice, the cache miss rate, and thus the signaling rate, remain
   low.


4.  Beyond scaling the Internet Routing Architecture

   LISP is more than just a scalability solution, it is also a tool to
   provide both incoming and outgoing traffic engineering ([S11],
   [I-D.farinacci-lisp-te]), it can be used as an IPv6 transition at the
   routing level, and it can be used for inter-domain multicast
   ([RFC6831], [I-D.coras-lisp-re]).  Also, LISP has been identified for
   use to support devices' Internet mobility ([I-D.meyer-lisp-mn]) and
   to support virtual machines' mobility in data centers and multi-
   tenant VPNs.  These last two uses are not discussed further as they
   are out of the scope of the current LISP Working Group charter.

   A key advantage of the LISP architecture is that it facilitates
   routing in environments where there is little to no correlation
   between network endpoints and topological location.  In service
   provider environments, this application is needed in a range of
   consumer use cases which require an inline anchor to deliver a
   service to a subscribers.  Inline anchors provide one of three types
   of capabilities:

   o  enable mobility of subscriber end points

   o  enable chaining of middle-box functions and services




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   o  enable seamless scale-out of functions

   Without LISP, the approach commonly used by operators is to aggregate
   service anchors in custom built boxes.  This limits deployments as
   end-points only can move on the same mobile gateway, functions can be
   chained only if traffic traverses the same wire or the same DPI box,
   and capacity can scale out only if traffic fans out to/from a
   specific load balancer.

   With LISP, service providers are able to distribute, virtualize, and
   instantiate subscriber-service anchors anywhere in the network.
   Typical use cases for virtualized inline anchors and network
   functions include: Distributed Mobility and Virtualized Evolved
   Packet Core (vEPC), Virtualized Customer Premise Equipment or vCPE,
   where functionality previously anchored at a customer premises is now
   dynamically allocated in-network, Virtualized SGi LAN, Virtual IMS
   and Virtual SBC, etc.

   ConteXtream ([ConteXtream]) has been deploying map-assisted overlay
   networks since 2006, first with a proprietary solution, then evolving
   to standard LISP.  The solution has been deployed in production in
   three tier-1 operators spanning hundreds of millions of subscribers.
   Map assisted overlays had been primarily used to map subscriber flows
   to services resources dynamically based on profiles and conditions.
   Specifically it has been used to map mobile subscribers to value-
   added/optimization services, broadband subscribes to telephony
   services, and fixed-mobile subscribers to BNG (Broadband Network
   Gateway) functions and Internet access services.  The LISP map-
   assisted overlay architecture is used to optimally resolve subscriber
   to services to functions to instances to IP overlay aggregation
   locations, just in time, per flow.

4.1.  Traffic engineering

   In the current (non-LISP)routing infrastructure, addresses used by
   stub networks are globally routable and the routing system
   distributes the routes to reach these stubs.  With LISP, the EID
   prefixes of a LISP site are not routable in the DFZ, mappings are
   needed in order to determine the list of LISP routers to contact to
   forward packets.  This difference is significant for two reasons.
   First, packets are not forwarded to a site but to a specific router.
   Second, a site can control the entry points for its traffic by
   controlling its mappings.

   For traffic engineering purposes, a mapping associates an EID prefix
   to a list of RLOCs.  Each RLOC is annotated with a priority and a
   weight.  When there are several RLOCs, the ITR selects the one with
   the highest priority and sends the encapsulated packet to this RLOC.



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   If several RLOCs with the highest priority exist, then the traffic is
   balanced proportionally to their weight among such RLOCs.  Traffic
   engineering in LISP thus allows the mapping owner to have a fine-
   grained control on the primary and backup path for its incoming and
   outgoing packets use.  In addition, it can share the load among its
   links.  An example of the use of such a feature is described by
   Saucez et al.  [SDIB08], showing how to use LISP to direct different
   types of traffic on different links having different capacity.

   Traffic engineering in LISP goes one step further.  As every Map-
   Request contains the Source EID Address of the packet that caused a
   cache miss and triggered the Map-Request.  It is thus possible for a
   mapping owner to differentiate the answer (Map-Reply) it gives to
   Map-Requests based on the requester.  This functionality is not
   available today with BGP because a domain cannot control exactly the
   routes that will be received by domains that are not in the direct
   neighborhood.

4.2.  LISP for IPv6 Co-existence

   The LISP encapsulation mechanism is designed to support any
   combination of locators and identifiers address family.  It is then
   possible to bind IPv6 EIDs with IPv4 RLOCs and vice-versa.  This
   allows transporting IPv6 packets over an IPv4 network (or IPv4
   packets over an IPv6 network), making LISP a valuable mechanism to
   ease the transition to IPv6.

   An example is the case of the network infrastructure of a datacenter
   being IPv4-only while dual-stack front-end load balancers are used.
   In this scenario, LISP can be used to provide IPv6 access to servers
   even though the network and the servers only support IPv4.  Assuming
   that the datacenter's ISP offers IPv6 connectivity, the datacenter
   only needs to deploy one (or more) xTR(s) at its border with the ISP
   and one (or more) xTR(s) directly connected to the load balancers.
   The xTR(s) at the ISP's border tunnels IPv6 packets over IPv4 to the
   xTR(s) directly attached to the load balancer.  The load balancer's
   xTR de-encapsulates the packets and forwards them to the load
   balancer, which act as proxies, translating each IPv6 packet into an
   IPv4.  IPv4 packets are then sent to the appropriate servers.
   Similarly, when the server's response arrives at the load balancer,
   the packet is translated back into an IPv6 packet and forwarded to
   its xTR(s), which in turn will tunnel it back, over the IPv4-only
   infrastructure, to an xTR connected to the ISP.  The packet is then
   de-encapsulated and forwarded to the ISP natively in IPv6.







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4.3.  Inter-domain multicast

   LISP has native support for multicast [RFC6831].  From the data-plane
   perspective, at a multicast enabled xTR, an EID sourced multicast
   packet is encapsulated in another multicast packet and subsequently
   forwarded in a RLOC-level distribution tree.  Therefore, xTRs must
   participate in both EID and RLOC level distribution trees.  Control-
   plane wise, since group addresses have no topological significance
   they need not to be mapped.  It is worth noting that, to properly
   function, LISP-Multicast requires that inter-domain multicast be
   available.

   LISP Replication Engineering (RE) ([I-D.coras-lisp-re], [CDM12])
   leverage LISP messages ([I-D.farinacci-lisp-mr-signaling]) for
   multicast state distribution to construct xTR based inter-domain
   multicast distribution trees when inter-domain multicast support is
   not available.  Simulations of three different management strategies
   for low latency content delivery show that such overlays can support
   thousands of member xTRs, hundreds of thousands of end-hosts and
   deliver content at latencies close to unicast ones ([CDM12]).  It was
   also observed that high client churn has a limited impact on
   performance and management overhead.

   Similarly to LISP-RE, Signal-Free LISP Multicast
   ([I-D.farinacci-lisp-signal-free-multicast]) can be used when the
   core network does not provide multicast support.  But instead of
   using signaling to build inter-domain multicast trees, signal-free
   exclusively leverages the map-server for multicast state storage and
   distribution.  As a result, the source ITR generally performs head-
   end replication but it might be also used to emulate LISP-RE
   distribution trees.


5.  Impact of LISP on operations and business models

   Numerous implementation efforts ([IOSNXOS], [OpenLISP], [LISPmob],
   [LISPClick], [LISPcp], and [LISPfritz]) have been made to assess the
   specifications and, additionally, interoperability tests ([Was09])
   have been successful.  A world-wide large deployment in the
   international lisp4.net testbed, which is currently composed of nodes
   running at least three different implementations, will allow us to
   learn further operational aspects related to LISP.

   The following sections distinguish the impact of LISP on LISP sites
   from the impact on non-LISP sites.






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5.1.  Impact on non-LISP traffic and sites

   LISP has no impact on traffic which has neither LISP origin nor LISP
   destination.  However, LISP can have a significant impact on traffic
   between a LISP site and a non-LISP site.  Traffic between a non-LISP
   site and a LISP site are subject to the same issues as those observed
   for LISP-to-LISP traffic but also have issues specific to the
   transition mechanism that allows the LISP site to exchange packets
   with a non-LISP site ([RFC6832], [RFC7215]).

   The transition requires setup of proxy tunnel routers (PxTRs).
   Proxies cause what is referred to as path stretch (i.e., a
   lengthening of the path compared to the topological shortest-path)
   and make troubleshooting harder.  There are still questions related
   to PxTRs that need to be answered:

   o  Where to deploy PxTRs?  The placement in the topology has an
      important impact on the path stretch.

   o  How many PxTRs?  The number of PxTR has a direct impact on the
      load and the impact of the failure of a PxTR on the traffic.

   o  What part of the EID space?  Will all the PxTRs be proxies for the
      whole EID space or will it be segmented between different PxTRs?

   o  Who operates PxTRs?  An important question to answer is related to
      the entities that will deploy PxTRs, how will they manage their
      additional CAPEX/OPEX costs associated with PxTRs?  How will the
      traffic be carried with respect to security and privacy?

   A PxTR will also normally advertise in BGP the EID prefix for which
   they are proxy.  However, if proxies are managed by different
   entities, they will belong to different ASes.  In this case, we need
   to be sure that this will not cause MOAS (Multi-Origin AS) issues
   that could negatively influence routing.  Moreover, it is important
   to ensure that the way EID prefixes will be de-aggregated by the
   proxies will remain reasonable so as not to contribute to BGP
   scalability issues.

5.2.  Impact on LISP traffic and sites

   LISP is a protocol based on the map-and-encap paradigm which has the
   positive impacts that we have summarized in the above sections.
   However, LISP also has impacts on operations:







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   MTU issue:  as LISP uses encapsulation, the MTU is reduced, this has
         implications on potentially all of the traffic.  However, in
         practice, on the lisp4.net network, no major issue due to the
         MTU has been observed.  This is probably due to the fact that
         current end-host stacks are well designed to deal with the
         problem of MTU.

   Resiliency issue:  the advantage of flexibility and control offered
         by the Locator/ID separation comes at the cost of increasing
         the complexity of the reachability detection.  Indeed,
         identifiers are not directly routable and have to be mapped to
         locators but a locator may be unreachable while others are
         still reachable.  This is an important problem for any tunnel-
         based solution.  In the current Internet, packets are forwarded
         independently of the border router of the network meaning that,
         in case of the failure of a border router, another one can be
         used.  With LISP, the destination RLOC specifically designates
         one particular ETR, hence if this ETR fails, the traffic is
         dropped, even though other ETRs are available for the
         destination site.  Another resiliency issue is linked to the
         fact that mappings are learned on demand.  When an ITR fails,
         all its traffic is redirected to other ITRs that might not have
         the mappings requested by the redirected traffic.  Existing
         studies ([SKI12], [SD12]) show, based on measurements and
         traffic traces, that failure of ITRs and RLOC are infrequent
         but that when such failure happens, a critical number of
         packets can be dropped.  Unfortunately, the current techniques
         for LISP resiliency, based on monitoring or probing are not
         rapid enough (failure recovery on the order of a few seconds).
         To tackle this issue [I-D.bonaventure-lisp-preserve] and
         [I-D.saucez-lisp-itr-graceful] propose techniques based on
         local failure detection and recovery.

   Middle boxes/filters:  because of increasingly common use of
         encryption as a response to pervasive monitoring ([RFC7258]),
         with LISP providing the option to encrypt traffic between xTRs
         ([I-D.ietf-lisp-crypto]), middle boxes are increasingly likely
         to be unable to understand encapsulated traffic, which can
         cause them to drop legitimate packets.  In addition, LISP
         allows triangular or even rectangular routing, so it is
         difficult to maintain a correct state even if the middle box
         understands LISP.  Finally, filtering may also have problems
         because they may think only one host is generating the traffic
         (the ITR), as long as it is not de-encapsulated.  To deal with
         LISP encapsulation, LISP aware firewalls that inspect inner
         LISP packets are proposed [lispfirewall].





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   Troubleshooting/debugging:  the major issue which LISP
         experimentation has shown is the difficulty of troubleshooting.
         When there is a problem in the network, it is hard to pin-point
         the reason as the operator only has a partial view of the
         network.  The operator can see what is in its EID-to-RLOC
         cache/database, and can try to obtain what is potentially
         elsewhere by querying the Map Resolvers, but the knowledge
         remains partial.  On top of that, ICMP packets only carry the
         first few tens of bytes of the original packet, which means
         that when an ICMP arrives at the ITR, it might not contain
         enough information to allow correct troubleshooting.
         Deployment in the beta network has shown that LISP+ALT
         ([RFC6836]) was not easy to maintain and control ([CCR13]),
         which explains the migration to LISP-DDT ([I-D.ietf-lisp-ddt]),
         based on a massively distributed and hierarchical approach
         ([CCR13]).

   Business/Operational-related:  Iannone et al.  [IL10] have shown that
         there are economical incentives to migrate to LISP, however,
         some questions remain.  For example, how will the EIDs be
         allocated to allow aggregation and hence scalability of the
         mapping system?  Who will operate the mapping system
         infrastructure and for what benefits?  What if several
         operators run different mapping systems?  How will they
         interoperate or share mapping information?

   Reachability:  The overhead related to RLOC reachability mechanisms
         is not known.


6.  IANA Considerations

   This document makes no request to the IANA.


7.  Security Considerations

   A thorough security and threats analysis of the LISP protocol is
   carried out in details in [I-D.ietf-lisp-threats].  Like for other
   Internet technologies, also for LISP most of threats can be mitigated
   using Best Current Practice, meaning with careful deployment an
   configuration (e.g., filter) and also by activating only features
   that are really necessary in the deployment and verifying all the
   information obtained from third parties.  Unless gleaning (Section 6
   of [RFC6836] and Section3.1 of [I-D.ietf-lisp-threats]) features are
   used, the LISP data-plane shows the same level of security as other
   IP-over-IP technologies.  From a security perspective, the control-
   plane remains the critical part of the LISP architecture.  To



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   mitigate the threats on the mapping system, authentication should be
   used for all control plane messages.  The current specification
   ([RFC6836], [I-D.ietf-lisp-sec]) defines security mechanisms which
   can reduce threats in open network environments.  The LISP
   specification defines a generic authentication data field for control
   plane messages ([RFC6836]) which could be used for a general
   authentication mechanisms for the LISP control-plane while staying
   backward compatible.


8.  Acknowledgments

   Thanks to Deborah Brungard, Ben Campbell, Spencer Dawkins, Stephen
   Farrel, Kathleen Moriarty, Hilarie Orman, and Wassim Haddad for their
   thorough reviews, comments, and suggestions.

   The people that contributed to this document are Alia Atlas, Sharon
   Barkai, Vince Fuller, Joel Halpern, Terry Manderson, Gregg Schudel,
   Ron Bonica, and Ross Callon.

   The work of Luigi Iannone has been partially supported by the ANR-13-
   INFR-0009 LISP-Lab Project (www.lisp-lab.org).


9.  References

9.1.  Normative References

   [I-D.ietf-lisp-threats]
              Saucez, D., Iannone, L., and O. Bonaventure, "LISP Threats
              Analysis", draft-ietf-lisp-threats-13 (work in progress),
              August 2015.

   [RFC6830]  Farinacci, D., Fuller, V., Meyer, D., and D. Lewis, "The
              Locator/ID Separation Protocol (LISP)", RFC 6830,
              DOI 10.17487/RFC6830, January 2013,
              <http://www.rfc-editor.org/info/rfc6830>.

   [RFC6831]  Farinacci, D., Meyer, D., Zwiebel, J., and S. Venaas, "The
              Locator/ID Separation Protocol (LISP) for Multicast
              Environments", RFC 6831, DOI 10.17487/RFC6831,
              January 2013, <http://www.rfc-editor.org/info/rfc6831>.

   [RFC6832]  Lewis, D., Meyer, D., Farinacci, D., and V. Fuller,
              "Interworking between Locator/ID Separation Protocol
              (LISP) and Non-LISP Sites", RFC 6832, DOI 10.17487/
              RFC6832, January 2013,
              <http://www.rfc-editor.org/info/rfc6832>.



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   [RFC6833]  Fuller, V. and D. Farinacci, "Locator/ID Separation
              Protocol (LISP) Map-Server Interface", RFC 6833,
              DOI 10.17487/RFC6833, January 2013,
              <http://www.rfc-editor.org/info/rfc6833>.

   [RFC6834]  Iannone, L., Saucez, D., and O. Bonaventure, "Locator/ID
              Separation Protocol (LISP) Map-Versioning", RFC 6834,
              DOI 10.17487/RFC6834, January 2013,
              <http://www.rfc-editor.org/info/rfc6834>.

   [RFC6836]  Fuller, V., Farinacci, D., Meyer, D., and D. Lewis,
              "Locator/ID Separation Protocol Alternative Logical
              Topology (LISP+ALT)", RFC 6836, DOI 10.17487/RFC6836,
              January 2013, <http://www.rfc-editor.org/info/rfc6836>.

   [RFC7215]  Jakab, L., Cabellos-Aparicio, A., Coras, F., Domingo-
              Pascual, J., and D. Lewis, "Locator/Identifier Separation
              Protocol (LISP) Network Element Deployment
              Considerations", RFC 7215, DOI 10.17487/RFC7215,
              April 2014, <http://www.rfc-editor.org/info/rfc7215>.

9.2.  Informative References

   [CCR13]    Saucez, D., Iannone, L., and B. Donnet, "A First
              Measurement Look at the Deployment and Evolution of the
              Locator/ID Separation Protocol",  ACM SIGCOMM Computer
              Communication Review. Vol. 43, N. 2., April 2013.

   [CDLC]     Coras, F., Domingo, J., Lewis, D., and A. Cabellos, "An
              Analytical Model for Loc/ID Mappings Caches",  IEEE
              Transactions on Networking, 2014.

   [CDM12]    Coras, F., Domingo-Pascual, J., Maino, F., Farinacci, D.,
              and A. Cabellos-Aparicio, "Lcast: Software-defined Inter-
              Domain Multicast",  Elsevier Computer Networks, July 2014.

   [ConteXtream]
              ConteXtream Software Company, "SDN and NFV solutions for
              carrier networks. (Further details on LISP only through
              private inquiry.)",  http://www.contextream.com.

   [I-D.bonaventure-lisp-preserve]
              Bonaventure, O., Francois, P., and D. Saucez, "Preserving
              the reachability of LISP ETRs in case of failures",
              draft-bonaventure-lisp-preserve-00 (work in progress),
              July 2009.

   [I-D.coras-lisp-re]



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              Coras, F., Cabellos-Aparicio, A., Domingo-Pascual, J.,
              Maino, F., and D. Farinacci, "LISP Replication
              Engineering", draft-coras-lisp-re-08 (work in progress),
              November 2015.

   [I-D.farinacci-lisp-mr-signaling]
              Farinacci, D. and M. Napierala, "LISP Control-Plane
              Multicast Signaling", draft-farinacci-lisp-mr-signaling-06
              (work in progress), February 2015.

   [I-D.farinacci-lisp-signal-free-multicast]
              Moreno, V. and D. Farinacci, "Signal-Free LISP Multicast",
              draft-farinacci-lisp-signal-free-multicast-03 (work in
              progress), June 2015.

   [I-D.farinacci-lisp-te]
              Farinacci, D., Kowal, M., and P. Lahiri, "LISP Traffic
              Engineering Use-Cases", draft-farinacci-lisp-te-09 (work
              in progress), September 2015.

   [I-D.ietf-lisp-crypto]
              Farinacci, D. and B. Weis, "LISP Data-Plane
              Confidentiality", draft-ietf-lisp-crypto-02 (work in
              progress), September 2015.

   [I-D.ietf-lisp-ddt]
              Fuller, V., Lewis, D., Ermagan, V., and A. Jain, "LISP
              Delegated Database Tree", draft-ietf-lisp-ddt-03 (work in
              progress), April 2015.

   [I-D.ietf-lisp-lcaf]
              Farinacci, D., Meyer, D., and J. Snijders, "LISP Canonical
              Address Format (LCAF)", draft-ietf-lisp-lcaf-11 (work in
              progress), September 2015.

   [I-D.ietf-lisp-sec]
              Maino, F., Ermagan, V., Cabellos-Aparicio, A., and D.
              Saucez, "LISP-Security (LISP-SEC)", draft-ietf-lisp-sec-09
              (work in progress), October 2015.

   [I-D.meyer-lisp-mn]
              Farinacci, D., Lewis, D., Meyer, D., and C. White, "LISP
              Mobile Node", draft-meyer-lisp-mn-13 (work in progress),
              July 2015.

   [I-D.saucez-lisp-itr-graceful]
              Saucez, D., Bonaventure, O., Iannone, L., and C. Filsfils,
              "LISP ITR Graceful Restart",



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              draft-saucez-lisp-itr-graceful-03 (work in progress),
              December 2013.

   [IB07]     Iannone, L. and O. Bonaventure, "On the cost of caching
              locator/id mappings",  In Proc. ACM CoNEXT 2007,
              December 2007.

   [IL10]     Iannone, L. and T. Leva, "Modeling the economics of Loc/ID
              Separation for the Future Internet",  Book Chapter,
              Towards the Future Internet - Emerging Trends from the
              European Research, IOS Press, May 2010.

   [IOSNXOS]  Cisco Systems Inc., "Locator/ID Separation Protocol
              (LISP)",  http://lisp4.cisco.com, 2013.

   [KIF13]    Kim, J., Iannone, L., and A. Feldmann, "Caching Locator/ID
              Mappings: Scalability Analysis and Implications",
               Elsevier Computer Networks Journal, March 2013.

   [LISPClick]
              Saucez, D. and V. Nguyen, "LISP-Click: A Click
              implementation of the Locator/ID Separation Protocol",
               1st Symposium on Click Modular Router, 2009,
              November 2009.

   [LISPcp]   "The lip6-lisp Project",  https://github.com/lip6-lisp/,
              2014.

   [LISPfritz]
              "Unsere FRITZ!Box-Produkte",
               http://avm.de/produkte/fritzbox/, 2014.

   [LISPmob]  "An open-source LISP implementation for Linux, Android and
              OpenWRT",  http://lispmob.org, 2015.

   [OpenLISP]
              "The OpenLISP Project",  http://www.openlisp.org, 2013.

   [QIdLB07]  Quoitin, B., Iannone, L., de Launois, C., and O.
              Bonaventure, "Evaluating the benefits of the locator/
              identifier separation",  In Proc. ACM MobiArch 2007,
              May 2007.

   [RFC4984]  Meyer, D., Ed., Zhang, L., Ed., and K. Fall, Ed., "Report
              from the IAB Workshop on Routing and Addressing",
              RFC 4984, DOI 10.17487/RFC4984, September 2007,
              <http://www.rfc-editor.org/info/rfc4984>.




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   [RFC7258]  Farrell, S. and H. Tschofenig, "Pervasive Monitoring Is an
              Attack", BCP 188, RFC 7258, DOI 10.17487/RFC7258,
              May 2014, <http://www.rfc-editor.org/info/rfc7258>.

   [S11]      Saucez, D., "Mechanisms for Interdomain Traffic
              Engineering with LISP",  PhD Thesis, Universite catholique
              de Louvain, 2011, October 2011.

   [SD12]     Saucez, D. and B. Donnet, "On the Dynamics of Locators in
              LISP",  In Proc. IFIP Networking 2012, May 2012.

   [SDIB08]   Saucez, D., Donnet, B., Iannone, L., and O. Bonaventure,
              "Interdomain Traffic Engineering in a Locator/Identifier
              Separation Context",  In Proc. of Internet Network
              Management Workshop, 2008, October 2008.

   [SKI12]    Saucez, D., Kim, J., Iannone, L., Bonaventure, O., and C.
              Filsfils, "A Local Approach to Fast Failure Recovery of
              LISP Ingress Tunnel Routers",  In Proc. IFIP Networking
              2012, May 2012.

   [Was09]    Wasserman, M., "LISP Interoperability Testing",  IETF 76,
              LISP WG presentation, 2009., November 2009.

   [lispfirewall]
              "LISP and Zone-Based Firewalls Integration and
              Interoperability",  http://www.cisco.com/c/en/us/td/docs/
              ios-xml/ios/sec_data_zbf/configuration/xe-3s/
              sec-data-zbf-xe-book/sec-zbf-lisp-inner-pac-insp.html,
              2014.


Authors' Addresses

   Damien Saucez
   INRIA
   2004 route des Lucioles BP 93
   06902 Sophia Antipolis Cedex
   France

   Email: damien.saucez@inria.fr










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   Luigi Iannone
   Telecom ParisTech
   23, Avenue d'Italie, CS 51327
   75214 PARIS Cedex 13
   France

   Email: ggx@gigix.net


   Albert Cabellos
   Technical University of Catalonia
   C/Jordi Girona, s/n
   08034 Barcelona
   Spain

   Email: acabello@ac.upc.edu


   Florin Coras
   Technical University of Catalonia
   C/Jordi Girona, s/n
   08034 Barcelona
   Spain

   Email: fcoras@ac.upc.edu


























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