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RPSL extensions for tunnels



	Folks,

	I didn't get a chance to present this in the BOF, so
	here's the draft. Any comments appreciated.

	Dave


-----------
INTERNET-DRAFT                                            David Meyer
draft-ietf-rps-tunnels-01.txt                    University of Oregon
Category: Standards Track                               November 1996


                      Representing Tunnels in RPSL


Status of this Memo

   This document provides extensions to the Routing Policy Specification
   Language [RPSL] to provide support for tunnels of various types.

Internet Drafts

   This document is an Internet-Draft.  Internet-Drafts are working
   documents of the Internet Engineering Task Force (IETF), its areas,
   and its working groups.  Note that other groups may also distribute
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   To learn the current status of any Internet-Draft, please check the
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   ftp.isi.edu (US West Coast).

Abstract

   This document specifies the language and set of semantics describing
   tunnels in the Routing Policy Specification Language (RPSL). It
   defines a new tunnel class, inet-tunnel, and a set of extensions to
   the inet-rtr class. An instance of the inet-tunnel class specifies
   endpoints for tunnels of various encapsulation types, including DVMRP
   [DVMRP], GRE [GRE], and IPv6 [IPV6].

   This memo is a product of the Routing Policy System Working Group
   (RPS) in the Operational Requirements area of the Internet Engineer-
   ing Task Force. Submit comments to <[email protected]> or the author.

Introduction

   Tunneling is a fundamental networking technology that is used in a
   variety circumstances. A common use of tunneling is to incrementally
   deploy a new network layer protocol. The approach is to encapsulate
   ("tunnel") the new protocol through the existing network layer proto-
   col, usually IP. Examples of this approach include include the multi-
   cast backbone [MBONE], where multicast packets are encapsulated in IP
   packets using protocol 4 (IP in IP), and IPv6 backbone [6BONE], where
   IPv6 packets are encapsulated in IP packets using IP protocol 41
   [V6TRNS].

   Another use of tunneling is to force congruence between the existing
   (IP unicast) topology and some new topology. Due the special require-
   ments of IP multicast routing, the MBONE is also an example of this
   use of tunneling.

   This document describes extensions to RPSL to support general tunnel-
   ing mechanisms. The extensions support point to point and point to
   multipoint tunnels of encapsulation types, including DVMRP, GRE, and
   IPv6. In addition to the encapsulation, a protocol to run inside the
   tunnel can also be specified.


Extensions to the inet-rtr class

   The inet-rtr class' peer attribute is extended to describe tunnels by
   assigning a new peer type (tunnel). The tunnel peer attribute has the
   following fields:


   inet-rtr: <name>
    ...
   peer: tunnel <dest-IP1> source=<source-IP1>
                encap=<encapsulation type>
                name=<name1>
    ...
   peer: tunnel <dest-IP2> source=<source-IP2>
                encap=<encapsulation type>
                name=<name2>



   The type clause of then tunnel peer attribute describes the encapsu-
   lation on the tunnel. The defined encapsulation types are DVMRP
   [DVMRP], GRE [GRE], or IPv6 [IPV6].  The name clause refers to a tun-
   nel object (see below). If there are multiple tunnel peer attributes
   with the same name attribute, then the tunnel is a point to mul-
   tipoint tunnel. Note that a router can be the source of multiple tun-
   nels.

   Each inet-rtr tunnel peer instance has a mandatory name, source, and
   destination attributes. The tunnel source attribute must correspond
   to an ifaddr attribute for the inet-rtr instance.

   The inet-rtr instance below describes a DVMRP tunnel with source
   204.70.32.6 and destination 204.70.158.61. The tag MBONE-TUNNEL-EUG
   refers to a tunnel instance (see below). The same router has a GRE
   tunnel.


   inet-rtr: eugene-isp.nero.net
   loacalas: AS4600
   ifaddr:   204.70.32.6 masklen 30
    ...
   peer: tunnel encap=DVMRP name=MBONE-TUNNEL-EUG 204.70.158.61 204.70.32.6
   peer: tunnel encap=GRE name=GRE-TUNNEL-EUG 206.42.19.240 204.70.32.6
    ...



The inet-tunnel Class

   A tunnel is specified by an instance of the inet-tunnel class. The
   attributes of the inet-tunnel class are described below.


   inet-tunnel:     <name>
   tunnel-source:   <inet-router key>
   tunnel-sink:     <inet-router key 1>
    ...
   tunnel-sink:     <inet-router key n>
   tunnel-protocol: <protocol>
   tunnel-in: from  <inet-router key1> accept <input-filter-spec1>
   tunnel-in: from  <inet-router key2> accept <input-filter-spec2>
    ...
   tunnel-in:  from <inet-router keyn> accept <input-filter-specn>
   tunnel-out: to   <inet-router key1>
                    [action
                      [scope=<ttl1>;]
                      [boundary=<prefixn/masklen1>;]
                      [dvmrp-metric=<n>;]]
                    announce <output-filter-spec1>
   tunnel-out: to   <inet-router key2>
                    [action
                      [scope=<ttl2>;]
                      [boundary=<prefixn/masklen2>;]
                      [dvmrp-metric=<n>;]]
                    announce <output-filter-spec2>
    ...
   tunnel-out: to   <inet-router keyn>
                    [action
                      [scope=<ttln>;]
                      [boundary=<prefixn/masklenn>;]
                      [dvmrp-metric=<n>;]]
                    announce <output-filter-specn>





inet-tunnel Class Attributes



   inet-tunnel:     mandatory, single valued
   tunnel-source:   mandatory, single valued, class key
   tunnel-sink:     mandatory, single valued, class key
   tunnel-protocol: mandatory, single valued
   tunnel-in:       mandatory, multi-valued
   tunnel-out:      mandatory, multi-valued



   An instance of the inet-tunnel class describes a single tunnel
   (although the tunnel-source may be the source of multiple tunnels).
   The name attribute is a key that is used in an inet-rtr object to
   reference the tunnel object. The tunnel may be point to point or
   point to multipoint. A multipoint tunnel will have more than one
   tunnel-sink value. Each tunnel-sink must have corresponding tunnel-in
   and tunnel-out attributes. The tunnel-protocol is the protocol to run
   "inside" the tunnel. The values for tunnel-protocol include BGP,
   RIPv6, DVMRP, PIM-DM, and PIM-SM. See [SSMMC] for an application that
   uses BGP tunneled in GRE.

   The inet-tunnel class's tunnel-out attribute includes an action
   clause for which the currently defined actions include: (i).  The
   minimum IP time-to-live required for a packet to be forwarded to the
   specified endpoint (in the case of multipoint tunnels, there may be
   per endpoint scopes), (ii). A boundary attribute describes a class of
   packets that will not be forwarded through the tunnel, and (iii). A
   DVMRP metric. These attributes are particularly relevant to multicast
   routing.

   The inet-tunnel class also has routing filter specifications which
   describe filters that are appropriate for the tunnel's routing proto-
   col. In the case of DVMRP, the filter specification
    can be the list of network prefixes accepted or advertised.

   Finally, an instance of the inet-tunnel class also has all of the
   administrative fields present in an aut-num class, including guar-
   dian, admin-c, tech-c, notify, mnt-by, changed, and source.




Example


   In this example, the inet-rtr eugene-isp.nero.net has a DVMRP tunnel
   with the sink on the inet-rtr dec3800-2-fddi-0.SanFrancisco.mci.net.
   The tunnel object is called MBONE-TUNNEL-EUG. eugene-isp.nero.net
   will accept any routes. eugene-isp.nero.net will forward packets to
   the DVMRP tunnel if the packet's time-to-live is greater than or
   equal to 64. In addition, eugene-isp.nero.net will not pass any pack-
   ets that match the administrative scope boundary filter (in this
   case, 239.254.0.0/16).

   In addition, the inet-rtr eugene-isp.nero.net has a GRE tunnel
   represented by GRE-TUNNEL-EUG.
















   inet-tunnel:     MBONE-TUNNEL-EUG
   tunnel-source:   204.70.158.61
   tunnel-sink:     204.70.32.6
   tunnel-protocol: DVMRP
   tunnel-in:       from 204.70.158.61 accept ANY
   tunnel-out:      to 204.70.158.61
                    action
                       scope=64;
                       boundary={239.254.0.0/16};
                       dvmrp-metric=1;
                    announce AS-NERO-TRANSIT
   guardian:    [email protected]
   admin-c:     DMM65
   tech-c:      DMM65
   notify:      [email protected]
   mnt-by:      MAINT-AS3582
   changed:     [email protected] 961122
   source:      RADB

   inet-tunnel:     GRE-TUNNEL-EUG
   tunnel-source:   204.70.158.61
   tunnel-sink:     206.42.19.240
   tunnel-protocol: PIM-DM
   tunnel-in:       from 206.42.19.240 accept ANY
   tunnel-out:      to 206.42.19.240
                    action
                      scope=64;
                    announce ANY
   guardian:    [email protected]
   admin-c:     DMM65
   tech-c:      DMM65
   notify:      [email protected]
   mnt-by:      MAINT-AS3582
   changed:     [email protected] 961122
   source:      RADB





Security Considerations

   Security considerations are not discussed in this memo.

References
      [6BONE]  See http://www-6bone.lbl.gov/6bone/

      [DVMRP]  T. Pusateri, "Distance Vector Multicast Routing
               Protocol", draft-ietf-idmr-dvmrp-v3-03, September,
               1996.

      [GRE]    S. Hanks, T. Li, D. Farinacci, and P. Traina, "Generic
               Routing Encapsulation (GRE)", RFC1701, October, 1994.

      [IPV6]   A. Conta and S. Deering, "Generic Packet Tunneling in
               IPv6", draft-ietf-ipngwg-ipv6-tunnel-04.txt, October,
               1996

      [MBONE]  See http://www.best.com/~prince/techinfo/misc.html

      [RPSL]   C. Alaettinoglu, et. al., "Routing Policy
               Specification Language (RPSL)",
               draft-ietf-rps-rpsl-00.txt, October, 1996.

      [SSMMC]  Y. Rekhter, "Auto route injection with tunnelling",
               NANOG, October, 1996. For additional information, see
               http://www.academ.com/nanog/oct1996/multihome.html

      [V6TRNS] R. Gilligan and E. Nordmark, "Transition Mechanisms
               for IPv6 Hosts and Routers", RFC 1933, April 1996.


Author's Address

   David Meyer
   University of Oregon
   1225 Kincaid St.
   Eugene, OR 97403

   phone:  +1 541.346.1747

   email:  [email protected]