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(See the Legal Provisions document at https://trustee.ietf.org/license-info for more information.) -- Couldn't find a document date in the document -- date freshness check skipped. Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) No issues found here. Summary: 7 errors (**), 0 flaws (~~), 9 warnings (==), 2 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Internet Engineering Task Force Chandrasekar Kathirvelu 3 INTERNET-DRAFT Karthik Muthukrishnan 4 Expires January 2002 Tom Walsh 5 Lucent Technologies 7 Andrew Malis Fred Ammann 8 Vivace Networks, Inc. COMMCARE telecommunications 10 July 2001 12 A Core MPLS IP VPN Link Broadcast And Virtual Router Discovery 13 15 Status of this Memo 17 This document is an Internet-Draft and is in full conformance with 18 all provisions of Section 10 of RFC2026. Internet-Drafts are 19 Working documents of the Internet Engineering Task Force (IETF), 20 its areas, and its working groups. Note that other groups may 21 also distribute working documents as Internet-Drafts. 23 Internet-Drafts are draft documents valid for a maximum of six 24 months and may be updated, replaced, or obsoleted by other 25 documents at any time. It is inappropriate to use Internet-Drafts 26 as reference material or to cite them other than as "work in 27 progress." 29 The list of current Internet-Drafts can be accessed at 30 http://www.ietf.org/ietf/1id-abstracts.txt. The list of 31 Internet-Draft Shadow Directories can be accessed at 32 http://www.ietf.org/shadow.html. 34 Abstract 36 An IPVPN consists of many routers, some physically discrete and 37 some virtual, housed in a Provider Edge router. The problem that 38 presents itself is that these virtual routers need to find each 39 other over a virtual topology and they need to send broadcast 40 datagrams as mandated in routing protocols [such as the neighbor 41 discovery datagram and routing updates in OSPF, the routing 42 updates in RIPV2 etc] and user data over this virtual topology. 43 This memo presents an approach for solving these problems. 45 1. Acronyms 46 ARP Address Resolution Protocol 47 CE Customer Edge router 48 LSP Label Switched Path 49 PNA Private Network Administrator 50 SLA Service Level Agreement 51 SP Service Provider 52 SPED Service Provider Edge Device 53 SPNA SP Network Administrator 54 VL Inter VR Virtual Link 55 VMA VPN Multicast Address 56 VPNID VPN Identifier 57 VR Virtual Router 58 VRC Virtual Router Console 60 2. Introduction 62 The two problems that need to be addressed are link level 63 broadcast and inter VR discovery over a virtual topology. 65 Broadly we can classify the solutions as static and dynamic. The 66 static approach calls for manually configuring the neighbor 67 address. This, while easy to articulate and effective for small 68 VPNs, is a configuration nightmare. Alternatively, this memo 69 describes an approach using an IP multicast infrastructure or ARP 70 servers for virtual routers to discover other virtual routers in a 71 given VPN and for supporting link level broadcast over a virtual 72 topology. 74 3. Static Approach 76 In this approach, we expect the user to configure a given VR's 77 neighbors in that VR. The exact mechanism is static ARP. 78 Basically, the user configures a static ARP entry for each 79 neighboring VR. The static ARP entry provides a mapping from the 80 neighboring VR's interface on the virtual link (VL) to the 81 backbone visible IP address of the neighbor's hosting PE. If this 82 methodology is used and the routing protocol(s) configured to run 83 over the VL require link broadcast, it has to be implemented using 84 non-native multicast forwarding paradigms; this is obviously less 85 than optimum from a network utilization standpoint. 87 4. Dynamic Approach 89 When the VPN is large with a large number of VRs associated with 90 it, a dynamic, automated method is preferable to static 91 configuration. This draft presents a IP multicast based approach 92 whereby dynamic ARP is used to discover the neighbor VR's PE 93 address and link broadcast is achieved using encapsulation of VPN 94 link broadcast packets in the multicast address assigned to the 95 VPN. 97 4.1. Using ARP for VR Discovery 99 In a physical LAN with a number of routers, when a data packet 100 needs to be forwarded to one of the other routers, an ARP request 101 is broadcast to the LAN. The router with the logical address 102 queried in the ARP request responds with an ARP response with its 103 MAC address. In identical fashion, the dynamic approach described 104 in this draft sends an ARP request to the multicast address 105 assigned to the VPN. The other VRs associated with this VPN 106 receive the ARP request and the appropriate VR responds with its 107 MAC address, i.e., its PE's backbone visible IP address. In order 108 to achieve this, we need to have a new hardware type field in the 109 ARP Req and Response. This enjoys the advantage that ARP is 110 implemented in almost all the SPEDs and CPEs and it is independent 111 of any routing protocols. 113 When we discuss the methods of carrying ARP, again it may depend 114 on the SP's network configuration. We discuss few methods here. 116 4.1.1. ARP over Multicast 118 If we assume that the SP's network supports multicast then each 119 VPN can subscribe to one multicast group as described in RFC 2917 120 and exchange the neighbor information. 122 4.2. Using Multicast For Link Broadcast 124 Some routing protocols, most notably IGPs, require link level 125 multicast facilities. For example, OSPF in broadcast mode uses 126 224.0.0.5 to discover other OSPF routers and to send route 127 updates, RIPv2 uses 224.0.0.9 to send route updates. If the 128 optimizations achieved with the use of these modes is desirable 129 over the VL, this approach calls for sending these routing 130 datagrams over the VPN's multicast address. This ensures that only 131 the VRs that participate in a given VPN receive these datagrams. 133 5. Intellectual Property Considerations 135 Lucent technologies may seek patent or other intellectual property 136 protection for some of all of the technologies disclosed in this 137 document. If any standards arising from this document are or 138 become protected by one or more patents assigned to Lucent 139 Technologies. Lucent Technologies intends to disclose those 140 patents and license them on reasonable and non-discriminatory 141 terms. 143 6. References 145 [muthuk] K.Muthukrishnan, A.Malis "A Core MPLS IP VPN Architecture", 146 RFC 2917 September 2000. 148 7. Authors' Addresses 150 Chandrasekar Kathirvelu 151 Lucent Technologies 152 1 Robbins Road 153 Westford, MA 01886 154 Phone: (978) 952-7116 155 EMail: ck32@lucent.com 157 Karthik Muthukrishnan 158 Lucent Technologies 159 1 Robbins Road 160 Westford, MA 01886 161 Phone: (978) 952-1368 162 EMail: mkarthik@lucent.com 164 Tom Walsh 165 Lucent Technologies 166 10 Lyberty Way 167 Westford, MA 01886 168 Phone: (978) 392-2311 169 EMail: tdwalsh@lucent.com 171 Fred Ammann 172 COMMCARE Telecommunications 173 Turmstrasse 8 174 CH-8952 Schlieren 175 Switzerland 176 Phone: +41 1 738 61 11 177 Email: fa@commcare.ch 179 Andrew Malis 180 Vivace Networks, Inc. 181 2730 Orchard Parkway 182 San Jose, CA 95134 183 Phone: (408) 383-7223 184 EMail: Andy.Malis@vivacenetworks.com 186 8. Full Copyright Statement 188 Copyright (C) The Internet Society (2000). All Rights Reserved. 190 This document and translations of it may be copied and furnished to 191 others, and derivative works that comment on or otherwise explain it 192 or assist in its implementation may be prepared, copied, published 193 and distributed, in whole or in part, without restriction of any 194 kind, provided that the above copyright notice and this paragraph are 195 included on all such copies and derivative works. However, this 196 document itself may not be modified in any way, such as by removing 197 the copyright notice or references to the Internet Society or other 198 Internet organizations, except as needed for the purpose of 199 developing Internet standards in which case the procedures for 200 copyrights defined in the Internet Standards process must be 201 followed, or as required to translate it into languages other than 202 English. 204 The limited permissions granted above are perpetual and will not be 205 revoked by the Internet Society or its successors or assigns. 207 This document and the information contained herein is provided on an 208 "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING 209 TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING 210 BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION 211 HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF 212 MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.