One document matched: draft-mrw-trill-over-ip-03.xml


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<rfc category="std" docName="draft-mrw-trill-over-ip-03.txt" ipr="trust200902">
  <front>
    <title abbrev="TRILL over IP">Transparent Interconnection of Lots of Links
    (TRILL) over IP</title>

    <author fullname="Margaret Wasserman" initials="M." surname="Wasserman">
      <organization>Painless Security</organization>

      <address>
        <postal>
          <street>356 Abbott Street</street>

          <city>North Andover</city>

          <region>MA</region>

          <code>01845</code>

          <country>USA</country>
        </postal>

        <phone>+1 781 405-7464</phone>

        <email>mrw@painless-security.com</email>

        <uri>http://www.painless-security.com</uri>
      </address>
    </author>

    <author fullname="Donald Eastlake" initials="D." surname="Eastlake">
      <organization>Huawei Technologies</organization>

      <address>
        <postal>
          <street>155 Beaver Street</street>

          <city>Milford</city>

          <region>MA</region>

          <code>01757</code>

          <country>USA</country>
        </postal>

        <phone>+1 508 333-2270</phone>

        <email>d3e3e3@gmail.com</email>
      </address>
    </author>

    <author fullname="Dacheng Zhang" initials="D." surname="Zhang">
      <organization>Huawei Technologies</organization>

      <address>
        <postal>
          <street>Q14, Huawei Campus</street>

          <street>No.156 Beiqing Rd.</street>

          <city>Beijing</city>

          <region>Hai-Dian District</region>

          <code>100095</code>

          <country>P.R. China</country>
        </postal>

        <phone/>

        <email>zhangdacheng@huawei.com</email>

        <uri/>
      </address>
    </author>

    <date day="16" month="October" year="2013"/>

    <area>Internet</area>

    <abstract>
      <t>The Transparent Interconnection of Lots of Links (TRILL) protocol is
      implemented by devices called TRILL Switches or RBridges (Routing
      Bridges). TRILL supports both point-to-point and multi-access links and
      is designed so that a variety of link protocols can be used between
      TRILL switch ports. This document standardizes methods for encapsulating
      TRILL in IP(v4 or v6) to provide a unified TRILL campus.</t>
    </abstract>
  </front>

  <middle>
    <section title="Requirements Terminology">
      <t>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 <xref
      target="RFC2119"/>.</t>
    </section>

    <section title="Introduction">
      <t>TRILL switches (RBridges) are devices that implement the IETF TRILL
      protocol <xref target="RFC6325"/> <xref
      target="I-D.eastlake-isis-rfc6326bis"/> <xref
      target="I-D.ietf-trill-rfc6327bis"/>.</t>

      <t>RBridges provide transparent forwarding of frames within an arbitrary
      network topology, using least cost paths for unicast traffic. They
      support not only VLANs and Fine Grained Labels <xref
      target="I-D.ietf-trill-fine-labeling"/> but also multipathing of unicast
      and multi-destination traffic. They use IS-IS link state routing and
      encapsulation with a hop count. They are compatible with IEEE 802.1
      customer bridges, and can incrementally replace them.</t>

      <t>Ports on different RBridges can communicate with each other over
      various link types, such as Ethernet <xref target="RFC6325"/> or PPP
      <xref target="RFC6361"/>.</t>

      <t>This document defines a method for RBridges to communicate over
      UDP/IP(v4 or v6). TRILL over IP will allow remote, Internet-connected
      RBridges to form a single RBridge campus, or multiple TRILL over IP
      networks within a campus to be connected as a single TRILL campus via a
      TRILL over IP backbone.</t>

      <t>TRILL over IP connects RBridge ports using IPv4 or IPv6 as a
      transport in such a way that the ports appear to TRILL to be connected
      by a single multi-access link. Therefore, if more than two RBridge ports
      are connected via a single TRILL over IP link, any pair of them can
      communicate.</t>

      <t>To support the scenarios where RBridges are connected via links (such
      as the public Internet) that are not under the same administrative
      control as the TRILL campus, this document specifies the use of Datagram
      Transport Layer Security (DTLS) <xref target="RFC6347"/> to secure the
      communications between RBridges running TRILL over IP.</t>
    </section>

    <section title="Use Cases for TRILL over IP">
      <t>This section introduces two application scenarios (a remote office
      scenario and an IP backbone scenario) which cover the most typical of
      situations where network administrators may choose to use TRILL over an
      IP network.</t>

      <section title="Remote Office Scenario">
        <t>In the Remote Office Scenario, a remote TRILL network is connected
        to a TRILL campus across a multihop non-TRILL IP network, such as the
        public Internet. The TRILL network in the remote office becomes a
        logical part of TRILL campus, and nodes in the remote office can be
        attached to the same VLANs as local campus nodes. In many cases, a
        remote office may be attached to the TRILL campus by a single pair of
        RBridges, one on the campus end, and the other in the remote office.
        In this use case, the TRILL over IP link will often cross logical and
        physical IP networks that do not support TRILL, and are not under the
        same administrative control as the TRILL campus.</t>
      </section>

      <section title="IP Backbone Scenario">
        <t>In the IP Backbone Scenario, TRILL over IP is used to connect a
        number of TRILL networks to form a single TRILL campus. For example, a
        TRILL over IP backbone could be used to connect multiple TRILL
        networks on different floors of a large building, or to connect TRILL
        networks in separate buildings of a multi-building site. In this use
        case, there may often be several TRILL switches on a single TRILL over
        IP link, and the IP link(s) used by TRILL over IP are typically under
        the same administrative control as the rest of the TRILL campus.</t>
      </section>

      <section title="Important Properties of the Scenarios">
        <t>There are a number of differences between the above two application
        scenarios, some of which drive features of this specification. These
        differences are especially pertinent to the security requirements of
        the solution, how multicast data frames are handled, and how the TRILL
        switch ports discover each other.</t>

        <section title="Security Requirements">
          <t>In the IP Backbone Scenario, TRILL over IP is used between a
          number of RBridge ports, on a network link that is in the same
          administrative control as the remainder of the TRILL campus. While
          it is desirable in this scenario to prevent the association of rogue
          RBridges, this can be accomplished using existing IS-IS security
          mechanisms. There may be no need to protect the data traffic, beyond
          any protections that are already in place on the local network.</t>

          <t>In the Remote Office Scenario, TRILL over IP may run over a
          network that is not under the same administrative control as the
          TRILL network. Nodes on the network may think that they are sending
          traffic locally, while that traffic is actually being sent, in a
          UDP/IP tunnel, over the public Internet. It is necessary in this
          scenario to protect the integrity and confidentiality of user
          traffic, as well as ensuring that no unauthorized RBridges can gain
          access to the RBridge campus. The issues of protecting integrity and
          confidentiality of user traffic are addressed by using DTLS for both
          IS-IS frames and data frames between RBridges in this scenario.</t>
        </section>

        <section title="Multicast Handling">
          <t>In the IP Backbone scenario, native multicast may be supported on
          the TRILL over IP link. If so, it can be used to send TRILL IS-IS
          and multicast data packets, as discussed later in this document.
          Alternatively, multi-destination packets can be transmitted
          serially.</t>

          <t>In the Remote Office Scenario there will often be only one pair
          of RBridges connecting a given site and, even when multiple RBridges
          are used to connect a Remote Office to the TRILL campus, the
          intervening network may not provide reliable (or any) multicast
          connectivity. The issues such as complex key management also makes
          it difficult to provide strong data integrity and confidentiality
          protections for multicast traffic. For all of these reasons, the
          connections between local and remote RBridges will be treated like
          point-to-point links, and all TRILL IS-IS control messages and
          multicast data packets that are transmitted between the Remote
          Office and the TRILL campus will be serially transmitted, as
          discussed later in this document.</t>
        </section>

        <section title="RBridge Neighbor Discovery">
          <t>In the IP Backbone Scenario, RBridges that use TRILL over IP will
          use the normal TRILL IS-IS Hello mechanisms to discover the
          existence of other RBridges on the link <xref
          target="I-D.ietf-trill-rfc6327bis"/>, and to establish authenticated
          communication with those RBridges.</t>

          <t>In the Remote Office Scenario, a DTLS session will need to be
          established between RBridges before TRILL IS-IS traffic can be
          exchanged, as discussed below. In this case, one of the RBridges
          will need to be configured to establish a DTLS session with the
          other RBridge. This will typically be accomplished by configuring
          the RBridge at a Remote Office to initiate a DTLS session, and
          subsequent TRILL exchanges, with a TRILL over IP-enabled RBridge
          attached to the TRILL campus.</t>
        </section>
      </section>
    </section>

    <section title="TRILL Packet Formats">
      <t>To support the TRILL base protocol standard <xref target="RFC6325"/>.
      , two types of packets will be transmitted between RBridges: TRILL Data
      frames and TRILL IS-IS packets.</t>

      <section title="TRILL Data Packet">
        <t>The on-the-wire form of a TRILL Data packet in transit between two
        neighboring RBridges is as shown below:</t>

        <figure>
          <artwork><![CDATA[ 
	     
   +--------------+----------+----------------+-----------+
   | TRILL Data   |  TRILL   |  Native Frame  |   Link    |
   | Link Header  |  Header  |     Payload    |  Trailer  |
   +--------------+----------+----------------+-----------+
             
	  ]]></artwork>
        </figure>

        <t>Where the Encapsulated Native Frame is similar to Ethernet frame
        format with a VLAN tag or Fine Grained Label <xref
        target="I-D.ietf-trill-fine-labeling"/> but with no trailing Frame
        Check Sequence (FCS).</t>
      </section>

      <section title="TRILL IS-IS Packet">
        <t>TRILL IS-IS packets are formatted on-the-wire as follows:</t>

        <figure>
          <artwork><![CDATA[ 
	     
   +--------------+---------------+-----------+
   | TRILL IS-IS  |  TRILL IS-IS  |   Link    |
   | Link Header  |    Payload    |  Trailer  |
   +--------------+---------------+-----------+
             
	  ]]></artwork>
        </figure>

        <t>The Link Header and Link Trailer in these formats depend on the
        specific link technology. The Link Header usually contains one or more
        fields that distinguish TRILL Data from TRILL IS-IS. For example, over
        Ethernet, the TRILL Data Link Header ends with the TRILL Ethertype
        while the TRILL IS-IS Link Header ends with the L2-IS-IS Ethertype; on
        the other hand, over PPP, there are no Ethertypes but PPP protocol
        code points are included that distinguish TRILL Data from TRILL
        IS-IS.</t>

        <t>In TRILL over IP, we will use UDP/IP (v4 or v6) as the link header,
        and the TRILL packet type will be determined based on the UDP
        destination port number. In TRILL over IP, no Link Trailer is
        specified, although one may be added when the resulting IP packets are
        encapsulated for transmission on a network (e.g. Ethernet).</t>
      </section>
    </section>

    <section title="Link Protocol Specifics">
      <t>TRILL Data packets can be unicast to a specific RBridge or multicast
      to all RBridges on the link. TRILL IS-IS packets are always multicast to
      all other RBridge on the link (except for MTU PDUs, which may be
      unicast). On Ethernet links, the Ethernet multicast address All-RBridges
      is used for TRILL Data and All-IS-IS-RBridges for TRILL IS-IS.</t>

      <t>To properly handle TRILL base protocol packets on a TRILL over IP
      link, either native multicast mode must be enabled on that link, or
      multicast must be simulated using serial unicast, as discussed
      below.</t>

      <t>In TRILL Hello PDUs used on TRILL IP links, the IP addresses of the
      connected IP ports are their real SNPA (SubNetwork Point of Attachment)
      addresses and, for IPv6, the 16-byte IPv6 address is used; however, for
      easy of code re-use designed for common 48-bit SNPAs, for TRILL over
      IPv4, a 48-bit synthetic SNPA that looks like a unicast MAC address is
      constructed for use in the SNPA field of TRILL Neighbor TLVs <xref
      target="I-D.eastlake-isis-rfc6326bis"/><xref
      target="I-D.ietf-trill-rfc6327bis"/> on the link. This synthetic SNPA is
      as follows:</t>

      <t/>

      <figure>
        <artwork><![CDATA[    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  0xFE         |  0x00         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  IPv4 upper half              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  IPv4 lower half              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

]]></artwork>
      </figure>

      <t>This synthetic SNPA/MAC address has the local (0x02) bit on in the
      first byte and so cannot conflict with any globally unique 48-bit
      Ethernet MAC. However, at the IP level, where TRILL operates on an IP
      link, there are only IP stations, not MAC stations, so conflict on the
      link with a real MAC address would be impossible in any case.</t>
    </section>

    <section title="Port Configuration">
      <t>Each RBridge physical port used for a TRILL over IP link MUST have at
      least one IP (v4 or v6) address. Implementations MAY allow a single
      physical port to operate as multiple IPv4 and/or IPv6 logical ports.
      Each IP address constitutes a different logical port and the RBridge
      with those ports MUST associate a different Port ID with each logical
      port.</t>

      <t>TBD: MUST be able to configure a list of IP addresses for serial
      unicast. MUST be able to configure a non-standard IP multi-cast address
      if native multicast is being used.</t>
    </section>

    <section title="TRILL over UDP/IP Format">
      <t>The general format of a TRILL over UDP/IP packet is shown below.</t>

      <figure>
        <artwork><![CDATA[ 
	   
   +----------+--------+-----------------------+
   | IP       | UDP    |  TRILL                |
   | Header   | Header |  Payload              |
   +----------+--------+-----------------------+
           
	]]></artwork>
      </figure>

      <t>Where the UDP Header is as follows:</t>

      <figure>
        <artwork><![CDATA[ 
	   
   TBD
           
	]]></artwork>
      </figure>

      <t>The TRILL Payload starts with the TRILL Header (not including the
      TRILL Ethertype) for TRILL Data packets and starts with the 0x83
      Intradomain Routeing Protocol Discriminator byte (thus not including the
      L2-IS-IS Ethertype) for TRILL IS-IS packets.</t>
    </section>

    <section title="Handling Multicast ">
      <t>By default, both TRILL IS-IS packets and multi-destination TRILL Data
      packets are sent to an All-RBridges IPv4 or IPv6 multicast Address as
      appropriate (see Section 14); however, a TRILL over IP port may be
      configured to use serial unicast with a list of unicast addresses of
      other stations to which multi-destination packets are sent.</t>

      <t>TBD</t>
    </section>

    <section title="Use of DTLS">
      <t>All RBridges that support TRILL over IP MUST implement DTLS and
      support the use of DTLS to secure both TRILL IS-IS and TRILL data
      packets. When DTLS is used to secure a TRILL over IP link, the DTLS
      session MUST be fully established before any TRILL IS-IS or data frames
      are exchanged.</t>

      <t>RBridges that implement TRILL over IP SHOULD support the use of
      certificates for DTLS and, if they support certificates, MUST support
      the following algorithm: <list style="symbols">
          <t>TLS_RSA_WITH_AES_128_CBC_SHA <xref target="RFC5246"/></t>
        </list></t>

      <t>RBridges that support TRILL over IP MUST support the use of
      pre-shared keys for DTLS. If the communicating RBridges have IS-IS Hello
      authentication enabled with a pre-shared key, then, by default a key
      derived from that TRILL Hello pre-shared key is used for DTLS unless
      some other pre-shared key is configured. The following cryptographic
      algorithms MUST be supported for use with pre-shared keys: <list
          style="symbols">
          <t>TLS_PSK_WITH_AES_128_CBC_SHA <xref target="RFC5246"/></t>
        </list>If the derived default preshared key is used, it is derived as
      follows:</t>

      <t>HMAC-SHA256 (“TRILL IP”, IS-IS-shared key )</t>

      <t>In the above "|" indicates concatenation, HMAC-SHA256 is as described
      in <xref target="FIPS180"/> <xref target="RFC6234"/> and "TRILL IP" is
      the eight byte US ASCII <xref target="ASCII"/> string indicated.</t>
    </section>

    <section title="Transport Considerations">
      <section title="Recursive Ingress">
        <t>TRILL is designed to transport end station traffic to and from IEEE
        802.1Q conformant end stations and IP is frequently transported over
        IEEE 802.3 or similar protocols supporting 802.1Q conformant end
        stations. Thus, an end station data frame EF might get TRILL ingressed
        to TRILL(EF) which was then sent on a TRILL over IP over an 802.3 link
        resulting in an 802.3 frame of the form 802.3(IP(TRILL(EF))). There is
        a risk of such a packet being re-ingressed by the same TRILL campus,
        due to physical or logical misconfiguration, looping round, being
        further re-ingressed, etc. The packet might get discarded if it got
        too large but if fragmentation is enabled, it would just keep getting
        split into fragments that would continue to loop and grow and
        re-fragment until the path was saturated with junk and packets were
        being discarded due to queue overflow. The TRILL Header TTL would
        provide no protection because each TRILL ingress adds a new Header and
        TTL.</t>

        <t>To protect against this scenario, TRILL over IP output ports MUST
        be able to test whether a TRILL packet they are above to send is, in
        fact a TRILL ingress of a TRILL over IP over 802.3 or the like
        packets. That is, is it of the form TRILL(802.3(IP(TRILL(...))). If
        so, the default action of the TRILL over IP output port is to discard
        the packet. However, there are cases where some level of nested
        ingress is desired so it MUST be possible to configure the port to
        allow such packets.</t>
      </section>

      <section title="Fat Flows">
        <t>For the purpose of load balancing, it could be worthwhile to
        consider how to transport the TRILL packets over the Equal Cost
        Multiple Paths (ECMPs) existing in the IP path.</t>

        <t>The ECMP election for the IP traffics could be based, at least for
        IPv4, on the quintuple of the outer IP header { Source IP, Destination
        IP, Source Port, Destination Port, and IP protocol }. Such tuples,
        however, can be exactly the same for all TRILL Data packets between
        two RBridge ports, even if there is a huge amount of data being sent.
        Therefore, in order to support ECMP, a RBridge SHOULD set the Source
        Port as an entropy field for ECMP decisions. This idea is also
        introduced in <xref target="I-D.yong-tsvwg-gre-in-udp-encap"/>.</t>
      </section>

      <section title="Congestion Control">
        <t>TBD</t>

        <t/>
      </section>
    </section>

    <section title="MTU Considerations">
      <t>In TRILL each RBridge advertises the largest LSP frame it can accept
      (but not less than 1,470 bytes) on any of its interfaces (at least those
      interfaces with adjacencies to other RBridges in the campus) in its LSP
      number zero through the originatingLSPBufferSize TLV <xref
      target="RFC6325"/> <xref target="I-D.eastlake-isis-rfc6326bis"/>. The
      campus minimum MTU, denoted Sz, is then established by taking the
      minimum of this advertised MTU for all RBridges in the campus. Links
      that do not meet the Sz MTU are not included in the routing topology.
      This protects the operation of IS-IS from links that would be unable to
      accommodate some LSPs.</t>

      <t>A method of determining originatingLSPBufferSize for an RBridge with
      one or more TRILL over IP portsis described in <xref
      target="I-D.ietf-trill-clear-correct"/>. However, if an IP link either
      can accommodate jumbo frames or is a link on which IP fragmentation is
      enabled and acceptable, then it is unlikely that the IP link will be a
      constraint on the RBridge’s originatingLSPBufferSize. On the other
      hand, if the IP link can only handle smaller frames and fragmentation is
      to be avoided when possible, a TRILL over IP port might constrain the
      RBridge’s originatingLSPBufferSize. Because TRILL sets the minimum
      values of Sz at 1,470 bytes, there may be links that meet the minimum
      MTU for the IP protocol (1,280 bytes for IPv6, theoretically 68 bytes
      for IPv4) on which it would be necessary to enable fragmentation for
      TRILL use.</t>

      <t>The optional use of TRILL IS-IS MTU PDUs, as specified in <xref
      target="RFC6325"/> and <xref target="I-D.ietf-trill-rfc6327bis"/> can
      provide added assurance of the actual MTU of a link.</t>
    </section>

    <section title="Middlebox Considerations">
      <t>TBD</t>
    </section>

    <section title="Security Considerations">
      <t>TRILL over IP is subject to all of the security considerations for
      the base TRILL protocol <xref target="RFC6325"/>. In addition, there are
      specific security requirements for different TRILL deployment scenarios,
      as discussed in the "Use Cases for TRILL over IP" section above.</t>

      <t>This document specifies that all RBridges that support TRILL over IP
      MUST implement DTLS, and makes it clear that it is both wise and good to
      use DTLS in all cases where a TRILL over IP link will traverse a network
      that is not under the same administrative control as the rest of the
      TRILL campus. DTLS is necessary, in these cases to protect the privacy
      and integrity of data traffic.</t>

      <t>TRILL over IP is completely compatible with the use of IS-IS
      security, which can be used to authenticate RBridges before allowing
      them to join a TRILL campus. This is sufficient to protect against rogue
      RBridges, but is not sufficient to protect data packets that may be
      sent, in UDP/IP tunnels, outside of the local network, or even across
      the public Internet. To protect the privacy and integrity of that
      traffic, use DTLS.</t>

      <t>In cases were DTLS is used, the use of IS-IS security may not be
      necessary, but there is nothing about this specification that would
      prevent using both DTLS and IS-IS security together. In cases where both
      types of security are enabled, by default, a key derived from the IS-IS
      key will be used for DTLS.</t>
    </section>

    <section title="IANA Considerations">
      <t>IANA has allocated the following destination UDP Ports for the TRILL
      IS-IS and Data channels:</t>

      <figure>
        <artwork><![CDATA[ 
	   
       UDP Port           Protocol

       (TBD)              TRILL IS-IS Channel           
       (TBD)              TRILL Data Channel
           
	]]></artwork>
      </figure>

      <t>IANA has allocated one IPv4 and one IPv6 multicast address, as shown
      below, which correspond to the All-RBridges and All-IS-IS-RBridges
      multicast MAC addresses that the IEEE Registration Authority has
      assigned for TRILL. Because the low level hardware MAC address dispatch
      considerations for TRILL over Ethernet do not apply to TRILL over IP,
      one IP multicast address for each version of IP is sufficient.</t>

      <t>[Values recommended to IANA:]</t>

      <figure>
        <artwork><![CDATA[ 
	   
      Name                 IPv4              IPv6

      All-RBridges         233.252.14.0      FF0X:0:0:0:0:0:0:205
           
	]]></artwork>
      </figure>

      <t>Note: when these IPv4 and IPv6 multicast addresses are used and the
      resulting IP frame is sent over Ethernet, the usual IP derived MAC
      address is used.</t>

      <t>[Need to discuss scopes for IPv6 multicast (the "X" in the addresses)
      somewhere. Default to "site" scope but MUST be configurable?]</t>
    </section>

    <section title="Acknowledgements">
      <t>This document was written using the xml2rfc tool described in RFC
      2629 <xref target="RFC2629"/>.</t>

      <t>The following people have provided useful feedback on the contents of
      this document: Sam Hartman, Adrian Farrel.</t>
    </section>
  </middle>

  <back>
    <references title="Normative References">
      &rfc2119;

      <reference anchor="ASCII">
        <front>
          <title>"USA Code for Information Interchange", ANSI
          X3.4-1968</title>

          <author fullname="American National Standards Institute (formerly United          States of America Standards Institute) ">
            <organization/>
          </author>

          <date year="1968"/>
        </front>
      </reference>

      <?rfc include='reference.I-D.ietf-trill-clear-correct'?>

      <?rfc include='reference.I-D.eastlake-isis-rfc6326bis'?>

      <?rfc include='reference.I-D.ietf-trill-rfc6327bis'?>

      <reference anchor="FIPS180">
        <front>
          <title>"Secure Hash Standard (SHS)"</title>

          <author fullname="United States of American,          National Institute of Science and Technology, Federal          Information Processing Standard (FIPS) 180-4 ">
            <organization/>
          </author>

          <date month="March" year="2012"/>
        </front>
      </reference>

      &rfc6325;

      &rfc5246;
    </references>

    <references title="Informative References">
      &rfc2629;

      &rfc6361;

      <?rfc include='reference.RFC.6347'?>

      <?rfc include='reference.RFC.6234'?>

      <?rfc include='reference.I-D.ietf-trill-fine-labeling'?>

      <?rfc include='reference.I-D.yong-tsvwg-gre-in-udp-encap'?>
    </references>
  </back>
</rfc>

PAFTECH AB 2003-20262026-04-24 01:51:46