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RPSL extensions for tunnels


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


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

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   documents of the Internet Engineering Task Force (IETF), its areas,
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   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.


   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

   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>
   peer: tunnel <dest-IP2> source=<source-IP2>
                encap=<encapsulation type>

   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-

   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 and destination The tag MBONE-TUNNEL-EUG
   refers to a tunnel instance (see below). The same router has a GRE

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

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>
                    announce <output-filter-spec1>
   tunnel-out: to   <inet-router key2>
                    announce <output-filter-spec2>
   tunnel-out: to   <inet-router keyn>
                    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

   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.


   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

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

   inet-tunnel:     MBONE-TUNNEL-EUG
   tunnel-protocol: DVMRP
   tunnel-in:       from accept ANY
   tunnel-out:      to
                    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-protocol: PIM-DM
   tunnel-in:       from accept ANY
   tunnel-out:      to
                    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.

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

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

      [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,

      [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

      [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]