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Internet Engineering Task Force (IETF)                      D. FarinacciRequest for Comments: 6835                                      D. MeyerCategory: Informational                                    Cisco SystemsISSN: 2070-1721                                             January 2013The Locator/ID Separation Protocol Internet Groper (LIG)Abstract   A simple tool called the Locator/ID Separation Protocol (LISP)   Internet Groper or 'lig' can be used to query the LISP mapping   database.  This document describes how it works.Status of This Memo   This document is not an Internet Standards Track specification; it is   published for informational purposes.   This document is a product of the Internet Engineering Task Force   (IETF).  It represents the consensus of the IETF community.  It has   received public review and has been approved for publication by the   Internet Engineering Steering Group (IESG).  Not all documents   approved by the IESG are a candidate for any level of Internet   Standard; seeSection 2 of RFC 5741.   Information about the current status of this document, any errata,   and how to provide feedback on it may be obtained athttp://www.rfc-editor.org/info/rfc6835.Copyright Notice   Copyright (c) 2013 IETF Trust and the persons identified as the   document authors.  All rights reserved.   This document is subject toBCP 78 and the IETF Trust's Legal   Provisions Relating to IETF Documents   (http://trustee.ietf.org/license-info) in effect on the date of   publication of this document.  Please review these documents   carefully, as they describe your rights and restrictions with respect   to this document.  Code Components extracted from this document must   include Simplified BSD License text as described in Section 4.e of   the Trust Legal Provisions and are provided without warranty as   described in the Simplified BSD License.Farinacci & Meyer             Informational                     [Page 1]

RFC 6835               LISP Internet Groper (LIG)           January 2013Table of Contents1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .22.  Definition of Terms  . . . . . . . . . . . . . . . . . . . . .33.  Basic Overview . . . . . . . . . . . . . . . . . . . . . . . .54.  Implementation Details . . . . . . . . . . . . . . . . . . . .64.1.  LISP Router Implementation . . . . . . . . . . . . . . . .64.2.  Public Domain Host Implementation  . . . . . . . . . . . .85.  Testing the ALT  . . . . . . . . . . . . . . . . . . . . . . .96.  Future Enhancements  . . . . . . . . . . . . . . . . . . . . .107.  Deployed Network Diagnostic Tools  . . . . . . . . . . . . . .108.  Security Considerations  . . . . . . . . . . . . . . . . . . .109.  References . . . . . . . . . . . . . . . . . . . . . . . . . .119.1.  Normative References . . . . . . . . . . . . . . . . . . .119.2.  Informative References . . . . . . . . . . . . . . . . . .11Appendix A.  Acknowledgments . . . . . . . . . . . . . . . . . . .121.  Introduction   The Locator/ID Separation Protocol [RFC6830] specifies an   architecture and mechanism for replacing the addresses currently used   by IP with two separate namespaces: Endpoint IDs (EIDs), used within   sites, and Routing Locators (RLOCs), used on the transit networks   that make up the Internet infrastructure.  To achieve this   separation, LISP defines protocol mechanisms for mapping from EIDs to   RLOCs.  In addition, LISP assumes the existence of a database to   store and propagate those mappings globally.  Several such databases   have been proposed, among them: a Content distribution Overlay   Network Service for LISP [LISP-CONS], a Not-so-novel EID-to-RLOC   Database (LISP-NERD) [RFC6837], and LISP Alternative Topology (LISP+   ALT) [RFC6836], with LISP+ALT being the system that is currently   being implemented and deployed on the pilot LISP network.   In conjunction with the various mapping systems, there exists a   network-based API called LISP Map-Server [RFC6833].  Using Map-   Resolvers and Map-Servers allows LISP sites to query and register   into the database in a uniform way independent of the mapping system   used.  Sending Map-Requests to Map-Resolvers provides a secure   mechanism to obtain a Map-Reply containing the authoritative EID-to-   RLOC mapping for a destination LISP site.   The 'lig' is a manual management tool to query the mapping database.   It can be run by all devices that implement LISP, including Ingress   Tunnel Routers (ITRs), Egress Tunnel Routers (ETRs), Proxy-ITRs,   Proxy-ETRs, Map-Resolvers, Map-Servers, and LISP-ALT Routers, as well   as by a host system at either a LISP-capable or non-LISP-capable   site.Farinacci & Meyer             Informational                     [Page 2]

RFC 6835               LISP Internet Groper (LIG)           January 2013   The mapping database system is typically a public database used for   wide-range connectivity across Internet sites.  The information in   the public database is purposely not kept private so it can be   generally accessible for public use.2.  Definition of Terms   Map-Server:   a network infrastructure component that learns EID-to-      RLOC mapping entries from an authoritative source (typically, an      ETR, though static configuration or another out-of-band mechanism      may be used).  A Map-Server advertises these mappings in the      distributed mapping database.   Map-Resolver:   a network infrastructure component that accepts LISP      Encapsulated Map-Requests, typically from an ITR, quickly      determines whether or not the destination IP address is part of      the EID namespace; if it is not, a Negative Map-Reply is      immediately returned.  Otherwise, the Map-Resolver finds the      appropriate EID-to-RLOC mapping by consulting the distributed      mapping database system.   Routing Locator (RLOC):   the IPv4 or IPv6 address of an Egress      Tunnel Router (ETR).  It is the output of an EID-to-RLOC mapping      lookup.  An EID maps to one or more RLOCs.  Typically, RLOCs are      numbered from topologically aggregatable blocks that are assigned      to a site at each point to which it attaches to the global      Internet.  Thus, the topology is defined by the connectivity of      provider networks, and RLOCs can be thought of as Provider-      Assigned (PA) addresses.  Multiple RLOCs can be assigned to the      same ETR device or to multiple ETR devices at a site.   Endpoint ID (EID):   a 32-bit (for IPv4) or 128-bit (for IPv6) value      used in the source and destination address fields of the first      (most inner) LISP header of a packet.  The host obtains a      destination EID the same way it obtains a destination address      today, for example, through a DNS lookup.  The source EID is      obtained via existing mechanisms used to set a host's "local" IP      address.  An EID is allocated to a host from an EID-prefix block      associated with the site where the host is located.  An EID can be      used by a host to refer to other hosts.  EIDs must not be used as      LISP RLOCs.  Note that EID blocks may be assigned in a      hierarchical manner, independent of the network topology, to      facilitate scaling of the mapping database.  In addition, an EID      block assigned to a site may have site-local structure      (subnetting) for routing within the site; this structure is not      visible to the global routing system.Farinacci & Meyer             Informational                     [Page 3]

RFC 6835               LISP Internet Groper (LIG)           January 2013   EID-to-RLOC Cache:   a short-lived, on-demand table in an ITR that      stores, tracks, and is responsible for timing-out and otherwise      validating EID-to-RLOC mappings.  This cache is distinct from the      full "database" of EID-to-RLOC mappings; the cache is dynamic,      local to the ITR(s), and relatively small, while the database is      distributed, relatively static, and much more global in scope.   EID-to-RLOC Database:   a global distributed database that contains      all known EID-prefix to RLOC mappings.  Each potential ETR      typically contains a small piece of the database: the EID-to-RLOC      mappings for the EID prefixes "behind" the router.  These map to      one of the router's own, globally-visible, IP addresses.   Encapsulated Map-Request (EMR):   an EMR is a Map-Request message      that is encapsulated with another LISP header using UDP      destination port number 4342.  It is used so an ITR, PITR, or a      system initiating a 'lig' command can get the Map-Request to a      Map-Resolver by using locator addresses.  When the Map-Request is      decapsulated by the Map-Resolver, it will be forwarded on the ALT      network to the Map-Server that has injected the EID-prefix for a      registered site.  The Map-Server will then encapsulate the Map-      Request in a LISP packet and send it to an ETR at the site.  The      ETR will then return an authoritative reply to the system that      initiated the request.  See [RFC6830] for packet format details.   Ingress Tunnel Router (ITR):   An ITR is a router that accepts an IP      packet with a single IP header (more precisely, an IP packet that      does not contain a LISP header).  The router treats this "inner"      IP destination address as an EID and performs an EID-to-RLOC      mapping lookup.  The router then prepends an "outer" IP header      with one of its globally routable RLOCs in the source address      field and the result of the mapping lookup in the destination      address field.  Note that this destination RLOC may be an      intermediate, proxy device that has better knowledge of the EID-      to-RLOC mapping closer to the destination EID.  In general, an ITR      receives IP packets from site end-systems on one side and sends      LISP-encapsulated IP packets toward the Internet on the other      side.   Egress Tunnel Router (ETR):   An ETR is a router that accepts an IP      packet where the destination address in the "outer" IP header is      one of its own RLOCs.  The router strips the "outer" header and      forwards the packet based on the next IP header found.  In      general, an ETR receives LISP-encapsulated IP packets from the      Internet on one side and sends decapsulated IP packets to site      end-systems on the other side.  ETR functionality does not have to      be limited to a router device.  A server host can be the endpoint      of a LISP tunnel as well.Farinacci & Meyer             Informational                     [Page 4]

RFC 6835               LISP Internet Groper (LIG)           January 2013   Proxy-ITR (PITR):   A PITR, also known as a PTR, is defined and      described in [RFC6832].  A PITR acts like an ITR but does so on      behalf of non-LISP sites that send packets to destinations at LISP      sites.   Proxy-ETR (PETR):   A PETR is defined and described in [RFC6832].  A      PETR acts like an ETR but does so on behalf of LISP sites that      send packets to destinations at non-LISP sites.   xTR:   An xTR is a reference to an ITR or ETR when direction of data      flow is not part of the context description. xTR refers to the      router that is the tunnel endpoint; it is used synonymously with      the term "tunnel router".  For example, "an xTR can be located at      the Customer Edge (CE) router" means that both ITR and ETR      functionality is at the CE router.   Provider-Assigned (PA) Addresses:   PA addresses are an address block      assigned to a site by each service provider to which a site      connects.  Typically, each block is a sub-block of a service-      provider Classless Inter-Domain Routing (CIDR) [RFC4632] block and      is aggregated into the larger block before being advertised into      the global Internet.  Traditionally, IP multihoming has been      implemented by each multihomed site acquiring its own globally      visible prefix.  LISP uses only topologically assigned and      aggregatable address blocks for RLOCs, eliminating this      demonstrably non-scalable practice.3.  Basic Overview   When the 'lig' command is run, a Map-Request is sent for a   destination EID.  When a Map-Reply is returned, the contents are   displayed to the user.  The information displayed includes:   o  The EID-prefix for the site that the queried destination EID      matches.   o  The locator address of the Map Replier.   o  The Locator-Set for the mapping entry, which includes the locator      address, up/down status, priority, and weight of each Locator.   o  A round-trip-time estimate for the Map-Request/Map-Reply exchange.   A possible syntax for a 'lig' command could be:       lig <destination> [source <source>] [to <map-resolver>]Farinacci & Meyer             Informational                     [Page 5]

RFC 6835               LISP Internet Groper (LIG)           January 2013   Parameter description:   <destination>:  is either a Fully Qualified Domain Name (FQDN) or a      destination EID for a remote LISP site.   source <source>:  is an optional source EID to be inserted in the      'Source EID' field of the Map-Request.   to <map-resolver>:  is an optional FQDN or RLOC address for a Map-      Resolver.   The 'lig' utility has two use cases.  The first is a way to query the   mapping database for a particular EID.  The other is to verify if a   site has registered successfully with a Map-Server.   The first usage has already been described.  Verifying registration   is called "ligging yourself"; it happens as follows.  In the 'lig'   initiator, a Map-Request is sent for one of the EIDs for the 'lig'   initiator's site.  The Map-Request is then returned to one of the   ETRs for the 'lig'-initiating site.  In response to the Map-Request,   a Map-Reply is sent back to the locator address of the 'lig'   initiator (note the Map-Reply could be sent by the 'lig' initiator).   That Map-Reply is processed, and the mapping data for the 'lig'-   initiating site is displayed for the user.  Refer to the syntax inSection 4.1 for an implementation of "ligging yourself".  However,   for host-based implementations within a LISP site, "lig self" is less   useful since the host may not have an RLOC with which to receive a   Map-Reply.  But, 'lig' can be used in a non-LISP site, as well as   from infrastructure hosts, to get mapping information.4.  Implementation Details4.1.  LISP Router Implementation   The Cisco LISP prototype implementation has support for 'lig' for   IPv4 and IPv6.  The command line description is:       lig <dest-eid> [source <source-eid>] [to <mr>] [count <1-5>]   This command initiates the LISP Internet Groper.  It is similar to   the DNS analogue 'dig' but works on the LISP mapping database.  When   this command is invoked, the local system will send a Map-Request to   the configured Map-Resolver.  When a Map-Reply is returned, its   contents will be displayed to the user.  By default, up to three Map-   Requests are sent if no Map-Reply is returned, but, once a Map-Reply   is returned, no other Map-Requests are sent.  The destination can   take a DNS name, or an IPv4 or IPv6 EID address.  The <source-eid>   can be one of the EID addresses assigned to the site in the defaultFarinacci & Meyer             Informational                     [Page 6]

RFC 6835               LISP Internet Groper (LIG)           January 2013   Virtual Routing and Forwarding (VRF) table.  When <mr> is specified,   then the Map-Request is sent to the address.  Otherwise, the Map-   Request is sent to a configured Map-Resolver.  When a Map-Resolver is   not configured, then the Map-Request is sent on the ALT network if   the local router is attached to the ALT.  When "count <1-5>" is   specified, 1, 2, 3, 4, or 5 Map-Requests are sent.   Some sample output:     router# lig abc.example.com     Send map-request to 10.0.0.1 for 192.168.1.1 ...     Received map-reply from 10.0.0.2 with rtt 0.081468 secs     Map-Cache entry for abc.example.com EID 192.168.1.1:     192.168.1.0/24, uptime: 13:59:59, expires: 23:59:58,                     via map-reply, auth       Locator          Uptime    State  Priority/Weight  Packets In/Out       10.0.0.2         13:59:59  up     1/100            0/14   Using 'lig' to "lig yourself" is accomplished with the following   syntax:       lig {self | self6} [source <source-eid>] [to <mr>] [count <1-5>]   Use this command for a simple way to see if the site is registered   with the mapping database system.  The destination-EID address for   the Map-Request will be the first configured EID-prefix for the site   (with the host bits set to 0).  For example, if the site's EID-prefix   is 192.168.1.0/24, the destination-EID for the Map-Request is   192.168.1.0.  The source-EID address for the Map-Request will also be   192.168.1.0 (in this example), and the Map-Request is sent to the   configured Map-Resolver.  If the Map-Resolver and Map-Server are the   same LISP system, then the "lig self" is testing if the Map-Resolver   can "turn back a Map-Request to the site".  If another Map-Resolver   is used, it can test that the site's EID-prefix has been injected   into the ALT infrastructure, in which case the 'lig' Map-Request is   processed by the Map-Resolver and propagated through each ALT-Router   hop to the site's registered Map-Server.  Then, the Map-Server   returns the Map-Request to the originating site.  In that case, an   xTR at the originating site sends a Map-Reply to the source of the   Map-Request (could be itself or another xTR for the site).  All other   command parameters are described above.  Using "lig self6" tests for   registering of IPv6 EID-prefixes.Farinacci & Meyer             Informational                     [Page 7]

RFC 6835               LISP Internet Groper (LIG)           January 2013   Some sample output for "ligging yourself":     router# lig self     Send loopback map-request to 10.0.0.1 for 192.168.2.0 ...     Received map-reply from 10.0.0.3 with rtt 0.001592 secs     Map-Cache entry for EID 192.168.2.0:     192.168.2.0/24, uptime: 00:00:02, expires: 23:59:57                     via map-reply, self       Locator       Uptime    State  Priority/Weight  Packets In/Out       10.0.0.3      00:00:02  up     1/100            0/0     router# lig self6     Send loopback map-request to 10.0.0.1 for 2001:db8:1:: ...     Received map-reply from 10::1 with rtt 0.044372 secs     Map-Cache entry for EID 192:168:1:::     2001:db8:1::/48, uptime: 00:00:01, expires: 23:59:58                      via map-reply, self       Locator          Uptime    State  Priority/Weight  Packets In/Out       10.0.0.3         00:00:01  up     1/100            0/0       2001:db8:ffff::1 00:00:01  up     2/0              0/04.2.  Public Domain Host Implementation   There is a public domain implementation that can run on any x86-based   system.  The only requirement is that the system that initiates 'lig'   must have an address assigned from the locator namespace.       lig [-d] <eid> -m <map-resolver> [-c <count>] [-t <timeout>]   Parameter description:   -d:  prints additional protocol debug output.   <eid>:  the destination EID or FQDN of a LISP host.   -m <map-resolver>:  the RLOC address or FQDN of a Map-Resolver.   -c <count>:  the number of Map-Requests to send before the first Map-      Reply is returned.  The default value is 3.  The range is from 1      to 5.   -t <timeout>:  the amount of time, in seconds, before another Map-      Request is sent when no Map-Reply is returned.  The default value      is 2 seconds.  The range is from 1 to 5.Farinacci & Meyer             Informational                     [Page 8]

RFC 6835               LISP Internet Groper (LIG)           January 2013   Some sample output:     % lig xyz.example.com -m 10.0.0.1     Send map-request to 10.0.0.1 for 192.168.1.1 ...     Received map-reply from 10.0.0.2 with rtt 0.04000 sec     Mapping entry for EID 192.168.1.1:     192.168.1.0/24, record ttl: 60      Locator           State     Priority/Weight      10.0.0.1          up        1/25      10.0.0.2          up        1/25      10.0.0.3          up        1/25      10.0.0.4          up        2/25   The public domain implementation of 'lig' is available at   <http://github.com/LISPmob/lig>.5.  Testing the ALT   There are cases where a Map-Reply is returned from a 'lig' request,   but the user doesn't really know how much of the mapping   infrastructure was tested.  There are two cases to consider --   avoiding the ALT and traversing the ALT.   When an ITR sends a 'lig' request to its Map-Resolver for a   destination-EID, the Map-Resolver could also be configured as a Map-   Server.  And if the destination-EID is for a site that registers with   this Map-Server, the Map-Request is sent to the site directly without   testing the ALT.  This occurs because the Map-Server is the source of   the advertisement for the site's EID-prefix.  So, if the map-reply is   returned to the 'lig'-requesting site, you cannot be sure that other   sites can reach the same destination-EID.   If a Map-Resolver is used that is not a Map-Server for the EID-prefix   being sought, then the ALT infrastructure can be tested.  This test   case is testing the functionality of the Map-Resolver, traversal of   the ALT (testing BGP-over-GRE), and the Map-Server.   It is recommended that users issue two 'lig' requests; they send Map-   Requests to different Map-Resolvers.   The network can have a LISP-ALT Router deployed as a "ALT looking-   glass" node.  This type of router has BGP peering sessions with other   ALT Routers where it does not inject any EID-prefixes into the ALT   but just learns ones advertised by other ALT Routers and Map-Servers.   This router is configured as a Map-Resolver. 'lig' users can point to   the ALT looking-glass router for Map-Resolver services via the "to   <map-resolver>" parameter on the 'lig' command.  The ALT looking-Farinacci & Meyer             Informational                     [Page 9]

RFC 6835               LISP Internet Groper (LIG)           January 2013   glass node can be used to 'lig' other sites as well as your own site.   When the ALT looking-glass is used as a Map-Resolver, you can be   assured the ALT network is being tested.6.  Future Enhancements   When Negative Map-Replies have been further developed and   implemented, 'lig' should be modified appropriately to process and   clearly indicate how and why a Negative Map-Reply was received.   Negative Map-Replies could be sent in the following cases: the 'lig'   request was initiated for a non-EID address or there was rate-   limiting on the replier.7.  Deployed Network Diagnostic Tools   There is a web-based interface to do auto-polling with 'lig' on the   back-end for most of the LISP sites on the LISP test network.  The   web page can be accessed at <http://www.lisp4.net/status>.   There is a LISP site monitoring web-based interface that can be found   at <http://lispmon.net>.   At <http://baldomar.ccaba.upc.edu/lispmon>, written by the folks at   Universitat Politecnica de Catalunya (UPC), shows a geographical map   indicating where each LISP site resides.8.  Security Considerations   The use of 'lig' does not affect the security of the LISP   infrastructure as it is simply a tool that facilities diagnostic   querying.  See [RFC6830], [RFC6836], and [RFC6833] for descriptions   of the security properties of the LISP infrastructure.   'lig' provides easy access to the information in the public mapping   database.  Therefore, it is important to protect the mapping   information for private use.  This can be provided by disallowing   access to specific mapping entries or to place such entries in a   private mapping database system.Farinacci & Meyer             Informational                    [Page 10]

RFC 6835               LISP Internet Groper (LIG)           January 20139.  References9.1.  Normative References   [RFC4632]    Fuller, V. and T. Li, "Classless Inter-domain Routing                (CIDR): The Internet Address Assignment and Aggregation                Plan",BCP 122,RFC 4632, August 2006.   [RFC6830]    Farinacci, D., Fuller, V., Meyer, D., and D. Lewis, "The                Locator/ID Separation Protocol (LISP)",RFC 6830,                January 2013.   [RFC6832]    Lewis, D., Meyer, D., Farinacci, D., and V. Fuller,                "Interworking between Locator/ID Separation Protocol                (LISP) and Non-LISP Sites",RFC 6832, January 2013.   [RFC6833]    Farinacci, D. and V. Fuller, "Locator/ID Separation                Protocol (LISP) Map Server Interface",RFC 6833,                January 2013.9.2.  Informative References   [LISP-CONS]  Farinacci, D., Fuller, V., and D. Meyer, "LISP-CONS: A                Content distribution Overlay Network Service for LISP",                Work in Progress, April 2008.   [RFC6836]    Farinacci, D., Fuller, V., Meyer, D., and D. Lewis,                "Locator/ID Separation Protocol Alternative Logical                Topology (LISP+ALT)",RFC 6836, January 2013.   [RFC6837]    Lear, E., "NERD: A Not-so-novel Endpoint ID (EID) to                Routing Locator (RLOC) Database",RFC 6837,                January 2013.Farinacci & Meyer             Informational                    [Page 11]

RFC 6835               LISP Internet Groper (LIG)           January 2013Appendix A.  Acknowledgments   Thanks and kudos to John Zwiebel, Andrew Partan, Darrel Lewis, and   Vince Fuller for providing critical feedback on the 'lig' design and   prototype implementations.  To these folks, as well as all the people   on lisp-beta@external.cisco.com who tested 'lig' functionality and   continue to do so, we extend our sincere thanks.   This document is based on an individual contribution.Authors' Addresses   Dino Farinacci   Cisco Systems   Tasman Drive   San Jose, CA  95134   USA   EMail: farinacci@gmail.com   Dave Meyer   Cisco Systems   170 Tasman Drive   San Jose, CA   USA   EMail: dmm@cisco.comFarinacci & Meyer             Informational                    [Page 12]