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     CCAMP Working Group                                     Zafar Ali
                                                         Hassan Sheikh
     Internet Draft                                Cisco Systems, Inc.
                                                        Tomohiro Otani
                                           KDDI R&D Laboratories, Inc.
                                                    Hidetsugu Sugiyama
                                                      Juniper Networks
     Intended status: BCP                            February 25, 2008
     Expires: August 2008
     
     
     
               Use of addresses in resolving ARP for GMPLS LSPs
     
          draft-ali-arp-over-gmpls-controlled-ethernet-psc-i-06.txt
     
     Status of this Memo
     
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     Copyright Notice
     
        Copyright (C) The IETF Trust (2007).
     
     
     
     
     
     
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          draft-ali-arp-over-gmpls-controlled-ethernet-psc-i-06.txt
     
     
     Abstract
     
        This document outlines some interoperability issues observed
        with the use of ARP over GMPLS controlled Ethernet router-to-
        router (PSC) interfaces transiting from a non-Ethernet core,
        e.g., FSC or LSC core. The document also recommends some
        procedures to address these issues. The aim of this document
        is to facilitate and ensure better interworking of GMPLS-
        capable Label Switching Routers (LSRs), based on experience
        gained in interoperability testing.
     
     Conventions used in this document
     
        In examples, "C:" and "S:" indicate lines sent by the client
        and server respectively.
     
        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 [RFC2119].
     
     Table of Contents
     
     
        1. Terminology...............................................2
        2. Introduction..............................................3
        3. Address to use for ARP Resolution.........................4
        4. Security Considerations...................................5
        5. IANA Considerations.......................................5
        6. References................................................5
           6.1. Normative References.................................5
           6.2. Informative References...............................5
        7. Author's Addresses........................................5
        8. Intellectual Property Statement...........................6
        9. Copyright Statement.......................................6
     
     1. Terminology
     
        The control plane address refers to the address assigned to
        the TE Links. This address is used to advertise TE link in the
        TE topology.
     
        The data plane address refers to the address assigned to the
        Ethernet data link or the address assigned to the GMPLS tunnel
        interface. This address is used at PSC (packet switching
        capable) layer for forwarding traffic over the GMPLS LSP. The
     
     
     
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        terms the data plane address and the GMPLS tunnel address are
        used synonymously.
     
     2. Introduction
     
        This draft addresses the scenario where edge routers are
        connected via a non-Ethernet switch capable GMPLS core, e.g.,
        FSC or LSC core [RFC3471], [RFC3473]. Furthermore, the
        interfaces between the router and the optical device (OXC) are
        Ethernet This draft addresses the case of TE numbered TE
        links. Furthermore, the LSP end-points may or may not be in
        the same subnets. The case where data links are unnumbered is
        beyond the scope of this document.
     
        When an LSP Path is established between the Ingress and Egress
        LSRs, Ethernet interface at the two LSRs comes up. Unlike POS
        links where a L2 adjacency resolution is not required, the
        Ethernet links require that the ARP be resolved (also known as
        Layer 2 MAC address) before any forwarding works on this link.
        Specifically, before a GMPLS LSP with Ethernet end-point can
        forward any IP traffic, MAC address of the remote router needs
        to be resolved. The remote MAC address learning is the same
        procedure used in ARP resolution to be able to map an ip
        address to a MAC address on an Ethernet Data Link.
     
        End-point MAC address needs to be re-learned once the ARP
        cache entries time-out, or every time the Ethernet Data Link
        path taken by the GMPLS LSP changes (e.g., due to re-routing
        or re-optimization). This introduces latency that is at least
        equal to the round trip delay. Such latency adds to the
        traffic switchover delay and consequently traffic loss for 1:1
        protected LSP without extra traffic, or when LSP route changes
        due to re-routing (restoration) or re-optimization, etc.
     
        Interoperability issues in learning end-point MAC address in
        the Ethernet Data Link using ARP are also found among vendors
        at various Interoperability events/ testing efforts. This is
        because different vendors use different IP address for ARP
        resolution. Some LSR vendor uses the control plane address of
        the TE link at the end-point, while others adapt to use data
        plane address on the Ethernet Data Link for ARP resolution.
     
        When GMPLS tunnel is protected, i.e., it has working and
        protecting LSP-es, the ARP requested for a given Ethernet IF
        address should resolve ARP for the physical Ethernet
        interfaces along the path of working and protecting LSP. Issue
        associated with ARP latency and traffic loss for 1:1 protected
     
     
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        LSP without extra traffic, or when LSP route changes due to
        re-routing (restoration) or re-optimization, etc. could not be
        addressed.
     
        This document provides recommendations for the use of the MAC
        addresses resolution (ARP resolution) for a GMPLS LSP. In the
        following, we provide reason behind recommendations provided
        in this document.
     
        Consider following scenarios.
     
        1. When the LSP end-points are in different subnets:
     
           In this case disjoint subnets are used with TE links
           between the Ingress LSR and the Optical node, and the
           Egress LSR and the optical node. In this situation we
           really have no way of resolving ARP using the addresses of
           the underlying TE link, without using static ARP entries.
           The issue is that the subnets are different so the ARP
           request received by Egress LSR from Ingress LSR will be
           rejected as it is not known to Egress LSR, and vice versa.
           This issue can be resolved when the ARP request uses
           Ethernet data link address. This is because the Ethernet
           data link is a logical link with IPV4 addresses in the
           same subnet.
     
        2. GMPLS Protection Case:
     
           The use of the protected Ethernet data link along with
           GMPLS LSP for ARP resolution can also extended to the case
           where the GMPLS tunnel is provided end-to-end 1:1
           protection i.e. a working LSP and a protected LSP of the
           GMPLS tunnel are typically using different physical
           interfaces (different MAC addresses) with different TE
           Link.  This issue can be resolved by using the same IP
           address and same MAC address for ARP resolution over
           working and protecting interfaces. The use of this
           implementation along with the creation of such mapping
           would also eliminate the problem of ARP cache timeout on
           the protected link; and hence can address the above-
           mentioned ARP latency issue related to protection case.
     
     3. Address to use for ARP Resolution
     
        An LSR SHOULD use data plane address on Ethernet data link for
        ARP request. For protected point-to-point interfaces, an LSR
        SHOULD resolve APR for two or more physical interfaces using
     
     
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        the same IP address and same MAC address (this is to address
        ARP Latency issue mentioned-above).
     
     
     4. Security Considerations
     
        TBA.
     
     
     5. IANA Considerations
     
        This document does not require any IANA consideration.
     
     6. References
     
     6.1. Normative References
     
        [RFC2119] "Key words for use in RFCs to Indicate Requirement
        Levels", S. Bradner, http://tools.ietf.org/html/rfc2119.
     
     6.2. Informative References
     
        [RFC3471] Generalized Multi-Protocol Label Switching (GMPLS)
           Signaling Functional Description, RFC 3471, L. Berger, et
           al, January 2003.
        [RFC3473] "Generalized Multi-Protocol Label Switching (GMPLS)
           Signaling Resource ReserVation Protocol-Traffic Engineering
           (RSVP-TE) Extensions", RFC 3473, L. Berger, et al, January
           2003.
     
     7. Author's Addresses
     
        Zafar Ali
        Cisco Systems Inc.
        2000 Innovation Dr.,
        Kanata, Ontario, K2K 3E8
        Canada.
        Phone: (613) 889-6158
        Email: zali@cisco.com
     
        Hassan Sheikh
        Cisco Systems Inc.
        2000 Innovation Dr.,
        Kanata, Ontario, K2K 3E8
        Canada.
        Phone: (613) 254-3356
     
     
     
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        Email: hassans@cisco.com
     
        Tomohiro Otani
        KDDI R&D Laboratories, Inc.
        2-1-15 Ohara Fujimino-shi
        Saitama, 356-8502. Japan
        Phone:  +81-49-278-7357
        Email:  otani@kddilabs.jp
     
        Hidetsugu Sugiyama
        Juniper Networks
        Email: hidet@juniper.net
     
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     9. Copyright Statement
     
     
           Copyright (C) The IETF Trust (2007).
     
           This document is subject to the rights, licenses and
        restrictions contained in BCP 78, and except as set forth
        therein, the authors retain all their rights.
     
     
     
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