Network Working Group Yiqun Cai
Internet Draft Eric C. Rosen (Editor)
Intended Status: Proposed Standard IJsbrand Wijnands
Expires: November 21, 2010 Cisco Systems, Inc.
May 21, 2010
MVPN: Customer IPv6 Using PIM Control Plane and S-PMSI Join Messages
draft-ietf-l3vpn-mvpn-spmsi-joins-00.txt
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Rosen, et al. [Page 1]
Internet Draft draft-ietf-l3vpn-mvpn-spmsi-joins-00.txt May 2010
described in the Simplified BSD License.
Abstract
The specification for Multicast Virtual Private Networks (MVPN)
contains an option that allows the use of PIM as the control protocol
between provider edge routers. It also contains an option that
allows UDP-based "S-PMSI Join" messages to be used to bind particular
customer multicast flows to particular tunnels through a service
provider's network. This document extends the MVPN specification so
that these options can be used when the customer multicast flows are
IPv6 flows.
Table of Contents
1 Specification of requirements ......................... 3
2 Introduction .......................................... 3
3 S-PMSI Joins Binding IPv6 Flows to GRE/IPv4 P-Tunnels . 3
3.1 Encoding .............................................. 4
3.2 Encapsulation of S-PMSI Joins in UDP Datagrams ........ 5
4 PE-PE PIM/IPv6 over an IPv4 P-Tunnel .................. 5
5 IANA Considerations ................................... 5
6 Security Considerations ............................... 6
7 Acknowledgments ....................................... 6
8 Authors' Addresses .................................... 6
9 Normative References .................................. 6
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1. Specification of requirements
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 [RFC2119].
2. Introduction
The Multicast Virtual Private Networks (MVPN) specification [MVPN]
allows PIM to be used as the control protocol between Provider Edge
(PE) routers. This requires PIM messages to be sent through a tunnel
(a "P-tunnel") from one PE in an MVPN to others in the same MVPN.
These PIM messages carry customer multicast routing information.
However, that specification does not cover the case where the
customer is using IPv6, but the service provider is using P-tunnels
created by PIM over an IPv4 infrastructure. The MVPN specification
also specifies "S-PMSI Join" messages, which are optionally used to
bind particular customer multicast flows to particular P-tunnels.
However, the specification does not cover the case where the customer
flows are IPv6 flows.
This document extends [MVPN] by adding the specifications for
handling customer IPv6 multicast flows when a service provider is
using PE-PE PIM and/or S-PMSI Join messages over an IPv4
infrastructure. This document also specifies how to send multiple
S-PMSI Join messages in a single UDP datagram.
This document uses terminology defined in [MVPN]: C-Source, C-Group,
C-flow, P-Group, (C-S,C-G)
3. S-PMSI Joins Binding IPv6 Flows to GRE/IPv4 P-Tunnels
The S-PMSI Join message is defined in section 7.4.2.2 of [MVPN].
These messages contain a type field, and [MVPN] defines only "Type 1"
S-PMSI Joins. A Type 1 S-PMSI Join may be used to assign a customer
IPv4 (C-S,C-G) flow to a P-tunnel that is created by PIM/IPv4.
GRE/IPv4 encapsulation is used to send data or control packets on the
P-tunnel.
In this document we define the Type 4 S-PMSI Join. A Type 4 S-PMSI
Join may be used to assign a customer IPv6 (C-S,C-G) flow to a
P-tunnel that is created by PIM/IPv4. GRE/IPv4 encapsulation is used
to send data or control packets on the P-tunnel.
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Internet Draft draft-ietf-l3vpn-mvpn-spmsi-joins-00.txt May 2010
3.1. Encoding
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| C-Source |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| C-Group |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| P-Group |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type (8 bits): 4
Length (16 bits): 40, the length in octets of the entire S-PMSI Join
message, including the Type, Length, Reserved, C-Source, C-Group, and
P-Group fields.
Reserved (8 bits): this field SHOULD be zero when transmitted, and
MUST be ignored when received.
C-Source (128 bits): the IPv6 address of the traffic source in the
VPN.
C-Group (128 bits): the IPv6 group address of the multicast traffic
P-Group (32 bits): the IPv4 group address identifying the P-tunnel.
Data packets sent on this tunnel are encapsulated in IPv4 GRE packets
with this group address in the IP destination address field of the
outer header.
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3.2. Encapsulation of S-PMSI Joins in UDP Datagrams
All S-PMSI Joins are encapsulated in UDP datagrams. A Type 4 S-PMSI
Join MUST be encapsulated in an IPv6 UDP datagram. The IPv6 source
address field of these datagrams SHOULD be the IPv4-mapped IPv6
address [RFC4291] corresponding to the IPv4 address that the
originating PE router uses as its source address in the instance of
PIM that is used to create the specified P-tunnel.
A single UDP datagram MAY carry multiple S-PMSI Join Messages, as
many as can fit entirely within it. If there are multiple S-PMSI
Joins in a UDP datagram, they MUST be of the same S-PMSI Join type.
The end of the last S-PMSI Join (as determined by the S-PMSI Join
length field) MUST coincide with the end of the UDP datagram, as
determined by the UDP length field. When processing a received UDP
datagram that contains one or more S-PMSI Joins, a router MUST
process all the S-PMSI Joins that fit into the datagram.
4. PE-PE PIM/IPv6 over an IPv4 P-Tunnel
If a VPN customer is using PIM over IPv6, but the SP is using an IPv4
infrastructure (i.e., is using an IPv4-based control protocol to
construct its P-tunnels), then the PE routers will need to originate
IPv6 PIM control messages. The IPv6 Source Address field of any such
IPv6 PIM control message SHOULD be the IPv4-mapped IPv6 address
[RFC4291] corresponding to the IPv4 address that the originating PE
router uses as its source address in the instance of PIM that is used
to create the specified P-tunnel. If the IPv6 Destination Address
field is the multicast address ALL-PIM-ROUTERS, the IPv6 form of the
address (ff02::d) is used. These IPv6 PIM control messages are of
course not transmitted natively over the service provider's network,
but rather are encapsulated in GRE/IPv4.
5. IANA Considerations
[MVPN] creates an IANA registry for the "S-PMSI Join Message Type
Field". This document requires that a new value be added to the
registry:
- The value 4 should be registered, and its description should read
"GRE S-PMSI for IPv6 traffic (unaggregated)".
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Internet Draft draft-ietf-l3vpn-mvpn-spmsi-joins-00.txt May 2010
6. Security Considerations
There are no additional security considerations beyond those of
[MVPN].
7. Acknowledgments
The authors wish to thank DP Ayadevara, Arjen Boers, Rayen Mohanty,
Rajesh Sharma, and Karthik Subramanian.
8. Authors' Addresses
Yiqun Cai
Cisco Systems, Inc.
170 Tasman Drive
San Jose, CA, 95134
E-mail: ycai@cisco.com
Eric C. Rosen
Cisco Systems, Inc.
1414 Massachusetts Avenue
Boxborough, MA, 01719
E-mail: erosen@cisco.com
IJsbrand Wijnands
Cisco Systems, Inc.
De kleetlaan 6a Diegem 1831
Belgium
E-mail: ice@cisco.com
9. Normative References
[MVPN] "Multicast in MPLS/BGP IP VPNs", Rosen, Aggarwal, et. al.,
draft-ietf-l3vpn-2547bis-mcast-10.txt, January 2010
[RFC2119] "Key words for use in RFCs to Indicate Requirement
Levels.", Bradner, March 1997
[RFC4291] "IPv6 Addressing Architecture", Hinden, Deering, February
2006
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