draft-ietf-softwire-mesh-framework-01.txt   draft-ietf-softwire-mesh-framework-02.txt 
Network Working Group J. Wu Network Working Group J. Wu
Internet Draft Y. Cui Internet Draft Y. Cui
Expiration Date: December 2007 X. Li Expiration Date: January 2008 X. Li
Tsinghua University Tsinghua University
C. Metz C. Metz
E. Rosen (Editor) E. Rosen (Editor)
S. Barber S. Barber
P. Mohapatra P. Mohapatra
Cisco Systems, Inc. Cisco Systems, Inc.
J. Scudder J. Scudder
Juniper Networks, Inc. Juniper Networks, Inc.
Softwire Mesh Framework Softwire Mesh Framework
draft-ietf-softwire-mesh-framework-01.txt draft-ietf-softwire-mesh-framework-02.txt
Status of this Memo Status of this Memo
By submitting this Internet-Draft, each author represents that any By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware applicable patent or other IPR claims of which he or she is aware
have been or will be disclosed, and any of which he or she becomes have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of BCP 79. aware will be disclosed, in accordance with Section 6 of BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
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kind" of data packet from one edge to the other. The tunnels are kind" of data packet from one edge to the other. The tunnels are
known as "Softwires". This framework document explains how the known as "Softwires". This framework document explains how the
routing information and the data packets of one protocol are passed routing information and the data packets of one protocol are passed
through a single protocol network of the other protocol. The through a single protocol network of the other protocol. The
document is careful to specify when this can be done with existing document is careful to specify when this can be done with existing
technology, and when it requires the development of new or modified technology, and when it requires the development of new or modified
technology. technology.
Table of Contents Table of Contents
1 Specification of requirements ......................... 2 1 Specification of requirements ......................... 4
2 Introduction .......................................... 2 2 Introduction .......................................... 4
3 Scenarios of Interest ................................. 5 3 Scenarios of Interest ................................. 7
3.1 IPv6-over-IPv4 Scenario ............................... 5 3.1 IPv6-over-IPv4 Scenario ............................... 7
3.2 IPv4-over-IPv6 Scenario ............................... 7 3.2 IPv4-over-IPv6 Scenario ............................... 9
4 General Principles of the Solution .................... 8 4 General Principles of the Solution .................... 11
4.1 'E-IP' and 'I-IP' ..................................... 8 4.1 'E-IP' and 'I-IP' ..................................... 11
4.2 Routing ............................................... 8 4.2 Routing ............................................... 11
4.3 Tunneled Forwarding ................................... 8 4.3 Tunneled Forwarding ................................... 12
5 Distribution of Inter-AFBR Routing Information ........ 9 5 Distribution of Inter-AFBR Routing Information ........ 12
6 Softwire Signaling .................................... 10 6 Softwire Signaling .................................... 14
7 Choosing to Forward Through a Softwire ................ 11 7 Choosing to Forward Through a Softwire ................ 16
8 Selecting a Tunneling Technology ...................... 11 8 Selecting a Tunneling Technology ...................... 16
9 Selecting the Softwire for a Given Packet ............. 12 9 Selecting the Softwire for a Given Packet ............. 17
10 Softwire OAM and MIBs ................................. 13 10 Softwire OAM and MIBs ................................. 18
10.1 Operations and Maintenance (OAM) ...................... 13 10.1 Operations and Maintenance (OAM) ...................... 18
10.2 MIBs .................................................. 13 10.2 MIBs .................................................. 19
11 Softwire Multicast .................................... 13 11 Softwire Multicast .................................... 19
11.1 One-to-One Mappings ................................... 14 11.1 One-to-One Mappings ................................... 20
11.1.1 Using PIM in the Core ................................. 14 11.1.1 Using PIM in the Core ................................. 20
11.1.2 Using mLDP and Multicast MPLS in the Core ............. 15 11.1.2 Using mLDP and Multicast MPLS in the Core ............. 21
11.2 MVPN-like Schemes ..................................... 15 11.2 MVPN-like Schemes ..................................... 22
12 Inter-AS Considerations ............................... 16 12 Inter-AS Considerations ............................... 23
13 IANA Considerations ................................... 17 13 IANA Considerations ................................... 24
14 Security Considerations ............................... 17 14 Security Considerations ............................... 24
14.1 Problem Analysis ...................................... 17 14.1 Problem Analysis ...................................... 24
14.2 Non-cryptographic techniques .......................... 18 14.2 Non-cryptographic techniques .......................... 25
14.3 Cryptographic techniques .............................. 18 14.3 Cryptographic techniques .............................. 27
15 Acknowledgments ....................................... 19 15 Acknowledgments ....................................... 28
16 Normative References .................................. 19 16 Normative References .................................. 28
17 Informative References ................................ 20 17 Informative References ................................ 29
18 Full Copyright Statement .............................. 22 18 Full Copyright Statement .............................. 32
19 Intellectual Property ................................. 23 19 Intellectual Property ................................. 32
1. Specification of requirements 1. Specification of requirements
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
2. Introduction 2. Introduction
The routing information in any IP backbone network can be thought of The routing information in any IP backbone network can be thought of
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consists of a single Autonomous System (AS). If the transit core consists of a single Autonomous System (AS). If the transit core
consists of multiple ASes, then it may be necessary to use softwires consists of multiple ASes, then it may be necessary to use softwires
whose endpoints are AFBRs attached to different Autonomous Systems. whose endpoints are AFBRs attached to different Autonomous Systems.
In this case, the AFBR at the remote endpoint of a softwire is not In this case, the AFBR at the remote endpoint of a softwire is not
the BGP next hop for packets that need to be sent on the softwire. the BGP next hop for packets that need to be sent on the softwire.
Since the procedures described above require the address of remote Since the procedures described above require the address of remote
softwire endpoint to be the same as the address of the BGP next hop, softwire endpoint to be the same as the address of the BGP next hop,
those procedures do not work as specified when the transit core those procedures do not work as specified when the transit core
consists of multiple ASes. consists of multiple ASes.
There are two ways to deal with this situation. There are several ways to deal with this situation.
1. Don't do it; require that there be AFBRs at the edge of each 1. Don't do it; require that there be AFBRs at the edge of each
AS, so that a transit core does not extend more than one AS. AS, so that a transit core does not extend more than one AS.
2. Specify a new BGP attribute that allows an AFBR to identify 2. Use multi-hop EBGP to allow AFBRs to send BGP routes to each
itself without using the NH field. This "next AFBR" attribute other, even if the ABFRs are not in the same or in neighboring
would be passed unchanged by non-AFBRs, but each AFBR ASes.
disseminating a given routing update would replace any existing
"next AFBR" attribute by its own address. When an ingress AFBR 3. Ensure that an ASBR which is not an AFBR does not change the
is choosing a softwire to send a packet through, if a "next next hop field of the routes for which encapsulation is needed.
AFBR" attribute is present, it would use that rather than the
next hop to help it choose the proper softwire. In the latter two cases, BGP recursive next hop resolution needs to
be done, and encapsulations may need to be stacked.
For instance, consider packet P with destination IP address D.
Suppose it arrives at ingress AFBR A1, and that the route that is the
best match for D has BGP next hop B1. So A1 will encapsulate the
packet for delivery to B1. If B1 is not within A1's AS, A1 will need
to look up the route to B1 and then find the BGP next hop, call it
B2, of that route. If the interior routers of A1's AS do not have
routes to B1, then A1 needs to encapsulate the packet a second time,
this time for delivery to B2.
13. IANA Considerations 13. IANA Considerations
This document has no actions for IANA. This document has no actions for IANA.
14. Security Considerations 14. Security Considerations
14.1. Problem Analysis 14.1. Problem Analysis
In the Softwires mesh framework, the data packets that are In the Softwires mesh framework, the data packets that are
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