Internet DRAFT - draft-geng-msr6-traffic-engineering
draft-geng-msr6-traffic-engineering
Network Working Group X. Geng
Internet-Draft Z. Li
Intended status: Standards Track J. Xie
Expires: 27 April 2023 Huawei Technologies
24 October 2022
IPv6 Multicast Source Routing Traffic Engineering
draft-geng-msr6-traffic-engineering-02
Abstract
This document defines 2 new types of segment: End.RL and End.RL.X ,
and the corresponding packet processing procedures over the IPv6 data
plane for the MSR6(Multicast Source Routing over IPv6) TE solutions.
Requirements Language
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].Ro
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
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Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on 27 April 2023.
Copyright Notice
Copyright (c) 2022 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminologies . . . . . . . . . . . . . . . . . . . . . . . . 3
3. MSR6 Explicit Routing . . . . . . . . . . . . . . . . . . . . 4
4. MSR6 SID Definition . . . . . . . . . . . . . . . . . . . . . 4
5. MSR6 Endpoint Behaviors . . . . . . . . . . . . . . . . . . . 5
5.1. End.RL: MSR6 Endpoint Replication List . . . . . . . . . 5
5.2. End.RL.X: MSR6 L3 Cross-Connect . . . . . . . . . . . . . 7
6. Multicast Routing Header . . . . . . . . . . . . . . . . . . 8
7. MSR6 Compression . . . . . . . . . . . . . . . . . . . . . . 10
7.1. MSR6 Requirement for Compression . . . . . . . . . . . . 10
7.2. Compressed MRH6 . . . . . . . . . . . . . . . . . . . . . 11
8. Illustration . . . . . . . . . . . . . . . . . . . . . . . . 12
8.1. MSR6 Illustration: End.RL . . . . . . . . . . . . . . . . 13
8.2. MSR6 Illustration: End.RL.X . . . . . . . . . . . . . . . 14
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15
10. Security Considerations . . . . . . . . . . . . . . . . . . . 15
11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 15
12. Normative References . . . . . . . . . . . . . . . . . . . . 15
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 17
1. Introduction
Segment Routing ([RFC8402]) leverages the mechanism of source
routing. An ingress node steers a packet through an ordered list of
instructions, called "segments". Each one of these instructions
represents a function to be implemented at a specific location in the
network. A function is locally defined on the node where it is
executed. Network Programming combines Segment Routing functions to
achieve a networking objective that goes beyond mere packet routing.
[RFC8986] defines the SRv6 Network Programming concept and specifies
the main Segment Routing behaviors and network programming functions.
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Bit Index Explicit Replication (BIER) [RFC8279] is an architecture
that provides optimal multicast forwarding without requiring a
protocol for explicitly building multicast distribution trees or per-
flow state maintained by intermediate routers. When a multicast data
packet enters BIER forwarding domain, the ingress node encapsulates
the packet with a bitstring, each bitposition of which presents the
egress nodes. To forward the packet to a given set of egress nodes,
the bits corresponding to those egress nodes are set in the
bitstring. The intermediate nodes in the BIER domain replicate and
forward the packet based on the bitstring.The mechanism of forwarding
a packet based on bitstring of BIER are specified in [RFC8279].
An IPv6 based multicast source routing (MSR6) solution is defined in
[I-D.cheng-spring-ipv6-msr-design-consideration], which leverages the
benefits of source routing over IPv6 data plane to provide simplified
multicast TE and BE service in an IPv6 network without unnecessary
multicast tree status and complex control plane protocols. MSR6
needs to reuse the advantages of SRv6 and BIER to implement source
routing.
MSR6 has two basic modes of forwarding: one is based on Shortest Path
First(SPF), which is called MSR6 BE mode; the other is based on
traffic engineered, which is called MSR6 TE mode. This document
defines 2 new types of segment: End.RL and End.RL.X , and the
corresponding packet processing procedures over the IPv6 data plane
for the MSR6 TE solutions.
2. Terminologies
MSR6: Multicast Source Routing over IPv6, defined in
[I-D.cheng-spring-ipv6-msr-design-consideration].
MRH: Multicast Routing Header, a new type of Routing Header which is
used for MSR6.
Multicast domain: A set of network device which could provide P2MP
multicast transport. In this document, the multicast domain is an
MSR domain, where every nodes support the capability of MSR6.
Root Node: Root node is the beginning point of a multicast tree and
also the initiation node of a multicast tunnel. It encapsulates the
packet with a multicast header. The type of the encapsulation
depends on the routing protocol used in the multicast domain. For
MSR6 TE, the encapsulation is MSR6 TE header, which is an IPv6 header
with MRH.
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Replication Endpoint: the intermediate node of a multicast tree,
which replicates packet and forwards the packet to the downstream
nodes. For MSR6, the Replication Node is called Replication Endpoint
which can be indicated by the MSR6 Segment and replicate packets
according to the multicast source routing information encapsulation
in the MSR6 header of the packet.
Leaf Node: Leaf node is the end point of a multicast tree and also
the decapsulation node of a multicast tunnel. It decapsulates the
multicast header in the packet and forwards the packet based on
overlay encapsulation.
Parent Node: The parent node is the node that does the packet
replication, corresponding to the concept of a child node.
Child Node: The child node is the downstream node that will receive
the packet which has been replicated ,corresponding to the concept of
a parent node.
3. MSR6 Explicit Routing
In order to implement MSR6 TE, the nodes and links along the path
must be explicitly specified in the packet.
In SRv6, the segment list is suitable for source route of unicast
path, which is P2P and could be presented by the data structure of a
chain with a pointer; In the Segment Routing Header(SRH), the segment
list is the chain, and the segment left is the pointer. But for the
multicast, the path of multicast service is a tree, and can not be
presented by data structure in a one-dimensional array. So this
document introduces new segment to present node/link in a multicast
tree and introduce structure information in the segment to indicate
the parent-child relationship during multicast replication. And all
the nodes/links along the multicast tree can be encoded into the
segment list.
In a multicast tree, when the packet is replicated from one node to
multiple downstream nodes, parent-child relationship is built up
between these nodes. MRH is supposed to encode the nodes along the
P2MP path and also the parent-child relationship between them.
4. MSR6 SID Definition
As defined in [RFC8402], an Segment Identifier is an IPv6 address
explicitly associated with the segment. When an SRv6 SID is in the
Destination Address field of an IPv6 header of a packet, it is routed
through transit nodes in an IPv6 network as an IPv6 address.
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MSR6 Segment Identifier complies with the definition of the Segment
Identifier in [RFC8402]. Following the specification in RFC8986, an
MSR6 SID is consisting of LOC:FUNCT:ARG. Locator could be
represented as B:N, B is the MSR6 segment block(IPv6 prefix allocated
for MSR6 segment by the operator) and N is the identifier of the node
instantiating the SID. The MSR6 locator is routable and leads to the
node which instantiates the SID; Function is the identification of a
local behavior bound to the MSR6 SID; Argument is the additional
information requested by the function.
Typical MSR6 functions and arguments are defined in the following
sections.
5. MSR6 Endpoint Behaviors
5.1. End.RL: MSR6 Endpoint Replication List
End.RL SID is one of the basic MSR6 SID as an extension of End SID
defined in RFC8986.
The encoding of segment list which is composed of End.RL SIDs follow
the rules:
* There MUST be an End.RL SID for each Replication Endpoint in the
multicast tree
* The End.RL SIDs, which represent child nodes that have the same
parent node, MUST be arranged consecutively in the segment list
* The End.RL SID for a parent node MUST indicate the position of the
End.RL SIDs for the child nodes
There are 2 arguments for each End.RL SID:
* "Replication number" is used for indicating how many times the
parent node is supposed to execute replication
* "Pointer" is used for indicating the position of End.RL SID for
the first child node in the segment list;
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When the packet is received by an Replication Endpoint and the DA of
this packet is a local SID with the function of End.RL, the packet
will be replicated based on the "replication number". The DA of the
1st replicated packet is replaced by the SL="pointer" and the value
of Segment Left is set to "pointer"; the DA of the 2nd replicated
packet is replaced by the SL="pointer -1" and the value of Segment
Left is set to "pointer-1". The packet is sent out based on the
updated DA. Repeat the operation untill all the replicated packets
are sent out.
The replication node does the following when the DA of the packet is
a local End.RL SID.
S01. When an MRH is processed {
S02. If (Segments Left == 0 or Replication Number==Pointer==0) {
S03. Stop processing the MRH, and proceed to process the next
header in the packet, whose type is identified by
the Next Header field in the routing header.
S04. }
S05. If (IPv6 Hop Limit <= 1) {
S06. Send an ICMP Time Exceeded message to the Source Address
with Code 0 (Hop limit exceeded in transit),
interrupt packet processing, and discard the packet.
S07. }
S08. max_LE = (Hdr Ext Len / 2) - 1
S09. If ((Last Entry > max_LE) or (Segments Left > Last Entry+1)) {
S10. Send an ICMP Parameter Problem to the Source Address
with Code 0 (Erroneous header field encountered)
and Pointer set to the Segments Left field,
interrupt packet processing, and discard the packet.
S11. }
S12. Decrement IPv6 Hop Limit by 1
S13. Replicate the packet based on the "replication number" in the
argument of the SID
S14. Set the Segment Left of the 1st replicated packet to "Pointer" in
the argument of the SID
S15. Update IPv6 DA with Segment List[Pointer]
respectively in each replicated packet
S16. Submit the packet to the egress IPv6 FIB lookup for
transmission to the new destination
S17. Repeat S14-S17 with "Pointer+n"(n=the number of packets which have
been updated) untill all the packets are transmitted to based
on the updated DA
R18. }
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5.2. End.RL.X: MSR6 L3 Cross-Connect
End.RL.X SID is one of the basic MSR6 SID as an extension of End.X
SID defined in RFC8986.
The encoding of segment list which is composed of End.RL.X SIDs
follow the rules:
* There MUST be an End.RL.X SID for each downstream link connected
to a Replication Endpoint in the multicast tree
* The End.RL.X SIDs corresponding to downstream links of the same
Replication Endpoint MUST be arranged consecutively in the segment
list
* The End.RL.X SID for a parent node MUST indicate the position of
the End.RL.X SIDs for the child nodes
There are 2 arguments for each End.RL SID:
* "Replication number" is used for indicating how many times the
existing node is supposed to execute replication
* "Pointer" is used for indicating the position of End.RL.X SID for
the first downstream link of the child node in the segment list;
When the packet is received by a Replication Endpoint and the DA of
this packet is a local SID with the function of End.RL.X, the packet
will be replicated based on the "replication number". The DA of the
1st replicated packet is replaced by the Segment List[ pointer ] and
the value of Segment Left is set to "pointer"; The packet is sent out
through the link indicated by the SID. the DA of the 2nd replicated
packet is replaced by the Segment List [SL +1] and the value of
Segment Left is set to "SL+1"; The DA of the 2nd packet is replaced
by the Segment List [ pointer2 ] (pointer2 is the argument in the
Segment List [SL+1]) and the value of Segment Left is set to
"pointer2"; The packet is sent out through the link indicated by the
SID; Repeat the operation untill all the replicated packets are sent
out through the indicated links.
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S01. When an MRH is processed {
S02. If (Segments Left == 0 or Replication Number==Pointer==0) {
S03. Stop processing the MRH, and proceed to process the next
header in the packet, whose type is identified by
the Next Header field in the routing header.
S04. }
S05. If (IPv6 Hop Limit <= 1) {
S06. Send an ICMP Time Exceeded message to the Source Address
with Code 0 (Hop limit exceeded in transit),
interrupt packet processing, and discard the packet.
S07. }
S08. max_LE = (Hdr Ext Len / 2) - 1
S09. If ((Last Entry > max_LE) or (Segments Left > Last Entry+1)) {
S10. Send an ICMP Parameter Problem to the Source Address
with Code 0 (Erroneous header field encountered)
and Pointer set to the Segments Left field,
interrupt packet processing, and discard the packet.
S11. }
S12. Decrement IPv6 Hop Limit by 1
S13. Replicate the packet based on the "replication number" in the
argument of the SID
S14. Set the Segment Left of the 1st replicated packet to "Pointer" in
the argument of the SID
S15. Update IPv6 DA with Segment List[Pointer]
S16. Transmit the packet through the indicated link
S17. Set the Segment Left of the 2nd replicated packet to "Segment Left+1" in
the argument of the SID
S18. Update IPv6 DA with Segment List[Segment Left+1]
S19. Set the Segment Left of the 2nd replicated packet to "Pointer 2" in
the argument of the updated SID
S20. Update IPv6 DA with Segment List[Pointer 2]
S21. Transmit the packet through the indicated link
S22. Repeat S17-S21 with "Pointer+n"(n=the number of packets which have
been updated) untill all the packets are transmitted to based
on the updated DA
R23. }
6. Multicast Routing Header
A new type of Routing Header is defined as follows for MSR6 Traffic
Engineering called Multicast Routing Header(MRH).
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Next Header | Hdr Ext Len | Routing Type | Segments Left |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MRH Sub-Type | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| M-SID[0] |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| M-SID[1] |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| ... |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| M-SID[n] |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// //
// Optional Type Length Value objects (variable) //
// //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Next Header: Defined in [RFC8200], section 4.4.
Hdr Ext Len: Defined in [RFC8200], section 4.4.
Routing Type: Allocated by IANA.
Segments Left: Defined in [RFC8200], section 4.4.
MRH Sub-type: 8-bit identifier of the sub-type. The value of sub-
type is supposed to be assigned by IANA.
Optional Type Length Value objects: TLV is used to carry other type
of information that is not suitable to indicated in the segment list.
The formart of M-SID defined in this document is shown in the
following figure:
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Locator |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Function |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Replication number | Pointer |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
It includes:
Locator: could represented as B:N where B is the MRH segment block
(IPv6 prefix allocated for MRH segment by the operator) and N is the
identifier of the node instantiating the SID. When the locator part
of the MRH segment is routable, it leads to the node, which
instantiates the SID.
Function: an identification of a local behavior bound to the MRH.
Replication is default behavior for any MRH segment, which doesn't
need function indication.
Replication number is used for indicating how many times the existing
node is supposed to excute replication
Pointer is used for indicating the position of MSR6 SID for the child
node;
Segments for the group of child nodes which belong to the same parent
node MUST be encoded together in the segment list. So Pointer and
replication number could determine the upper bound and lower bound of
the value range of segment left for the child nodes.
The destination address of the packet is the IPv6 address of the
existing Replication Endpoint. The next header of the IPv6 header
points to a Routing Header and the type of the routing header is MRH
Type.
7. MSR6 Compression
7.1. MSR6 Requirement for Compression
Different from unicast, MSR is designed for an explicit multicast
tree rather than a p2p path: the former contains more nodes than the
latter generally. So the header overhead is one of the key challenge
for MSR6, which limits the scalability and the potential deployment
scenario.
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There are some SRH compression solutions under discussion in IETF.
These solutions could also be used for MSR6 with modification.
7.2. Compressed MRH6
The compressed MRH6 is designed as follows:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Version | Traffic Class | Flow Label |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Payload Length | Next=43 | Hop Limit |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Source Address |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Common Prefix |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| M-SID [x] |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Next Header | Hdr Ext Len | Routing Type | Segments Left |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MRH Type=2 | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| M-SID[0] |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| M-SID[1] |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| M-SID[n] |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Each M-SID in the MRH is shown in the following figure:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Node-ID | Function | Rp Nm |Pointer|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
It includes:
Node ID: is the identifier of the node instantiating the SID. Common
Profix and Node ID together form a routable IPv6 address
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Function: an identification of a local behavior bound to the MRH.
Replication is default behavior for any MRH segment, which doesn't
need function indication.
Arguments: follow the definition in section 6, including replication
number and pointer.
The processing process is:
The destination address of the packet is the IPv6 address of the
existing Replication Endpoint. The next header of the IPv6 header
points to a Routing Header and the type of the routing header is MRH
Type 2. The Replication Endpoint is supposed to
* Find the next groups of segments in the MRH which present the
child nodes of the existing Replication Endpoint with Pointer-1
and Pointer-2;
* Replicate the packet based on the number of child nodes, which is
the replication number;
* Replace the SID part of IPv6 destination address with the
corresponding child node's segment in order for each replicated
packet;
* Update the segment left field of each replicated packet based on
the location child node's segment;
* Forward the packet to the output port based on the FIB with the
existing destination address as an entry;
8. Illustration
In order to
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+---+
+--| D |
+---+ B1 +---+
+--| B |----|
| +---+ B2 +---+
+---+ A1 +--| E |
| A |----| +---+
+---+ | +--| F |
A2 +---+ C1 +---+
+--| C |----|
+---+ C2 +---+
+--| G |
+---+
|-->MSR-R<--|->MSR End<-|-->MSR-L<--|
MSR-R: MSR6 Root Node, including Node A;
MSR End: MSR6 Replication Endpoint, including Node B and C;
MSR-L: MSR6 Leaf Nodes, including Node D, E, F, G;
8.1. MSR6 Illustration: End.RL
In node A, the packet is encapsulated the packet with an IPv6 header
carrying an MRH. The segment list in the MRH is as follows. The
destination address of the IPv6 header is the 1st SID in the segment
list, which is the local SID of node A. Based on the End.RL behavior
defined in section 5.1, the packet is replicated to 2 (Replication
Number+1=1+1=2) packets. In the 1st packet, the Segment Left is set
to 2 and DA is replaced by Segment List[2]; In the 2nd packet, the
Segment Left is set to 3 and DA is replaced by Segment List[3]; The
packets are routed to the node B and node C respectively.
+----------------------------------------+
| Loc:A | Fun:End.RL | Rp-Nm:1 | P:2 |
+----------------------------------------+
| Loc:B | Fun:End.RL | Rp-Nm:1 | P:4 |
+----------------------------------------+
| Loc:C | Fun:End.RL | Rp-Nm:1 | P:6 |
+----------------------------------------+
| Loc:D | Fun:End.RL | Rp-Nm:0 | P:0 |
+----------------------------------------+
| Loc:E | Fun:End.RL | Rp-Nm:0 | P:0 |
+----------------------------------------+
| Loc:F | Fun:End.RL | Rp-Nm:0 | P:0 |
+----------------------------------------+
| Loc:G | Fun:End.RL | Rp-Nm:0 | P:0 |
+----------------------------------------+
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In MSR6 Replication Endpoint B, the destination address of the IPv6
header is the local SID of node B. Based on the End.RL behavior
defined in section 5.1, the packet is replicated to 2 (Replication
Number+1=1+1=2) packets. In the 1st packet, the Segment Left is set
to 4 and DA is replaced by Segment List[4]; In the 2nd packet, the
Segment Left is set to 5 and DA is replaced by Segment List[5]; The
packets are routed to the node D and node E respectively.
In MSR Endpoint C, the process is similar.
In MSRE D, the destination address of the IPv6 header is the local
SID of node D. Based on the End.RL behavior defined in section 5.1,
when replication number=0, node D stops processing the MRH and
continues to process the next header in the packet.
8.2. MSR6 Illustration: End.RL.X
In node A, the packet is encapsulated the packet with an IPv6 header
carrying an MRH. The segment list in the MRH is as follows. The
destination address of the IPv6 header is the local SID of node A.
Based on the End.RL.X behavior defined in section 5.2, the packet is
replicated to 2 (Replication Number+1=1+1=2) packets. In the 1st
packet, the Segment Left is set to 3 and DA is replaced by Segment
List[3] and send the packet based on the specified adjacency A1; In
the 2nd packet, the Segment Left is set to 2 and DA is replaced by
Segment List[2]; Based on the arguments in the updated DA, the
Segment Left is set to 5 and DA is replaced by Segment List[5] and
send the packet based on the specified adjacency A2;
+-----------------------------------------+
| Loc:A1 | Fun:End.RL.X| Rp-Nm:1 | P:3 |
+-----------------------------------------+
| Loc:A2 | Fun:End.RL.X| Rp-Nm:0 | P:5 |
+-----------------------------------------+
| Loc:B1 | Fun:End.RL.X| Rp-Nm:1 | P:0 |
+-----------------------------------------+
| Loc:B2 | Fun:End.RL.X| Rp-Nm:0 | P:0 |
+-----------------------------------------+
| Loc:C1 | Fun:End.RL.X| Rp-Nm:1 | P:0 |
+-----------------------------------------+
| Loc:C2 | Fun:End.RL.X| Rp-Nm:0 | P:0 |
+-----------------------------------------+
In node B, the packet is encapsulated the packet with an IPv6 header
carrying an MRH. The segment list in the MRH is as follows. The
destination address of the IPv6 header is the local SID of node B.
Based on the End.RL.X behavior defined in section 5.2, the packet is
replicated to 2 (Replication Number+1=1+1=2) packets. In the 1st
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packet, the DA is replaced by the corresponding leaf stored in the
node and send the packet based on the specified adjacency B1; In the
2nd packet, the DA is replaced by the corresponding leaf stored in
the node and send the packet based on the specified adjacency B2;
In MSR Endpoint C, the process is similar.
In MSRE D, the destination address of the IPv6 header is the local
SID of node D. Node D stops processing the MRH, and begin to process
the next header in the packet.
9. IANA Considerations
This document makes no request of IANA.
Note to RFC Editor: this section may be removed on publication as an
RFC.
10. Security Considerations
11. Acknowledgements
12. Normative References
[I-D.cheng-spring-ipv6-msr-design-consideration]
Cheng, W., Mishra, G., Li, Z., Wang, A., Qin, Z., and C.
Fan, "Design Consideration of IPv6 Multicast Source
Routing (MSR6)", Work in Progress, Internet-Draft, draft-
cheng-spring-ipv6-msr-design-consideration-01, 25 October
2021, <https://www.ietf.org/archive/id/draft-cheng-spring-
ipv6-msr-design-consideration-01.txt>.
[I-D.geng-bier-ipv6-inter-domain]
Geng, L., Xie, J., McBride, M., Yan, G., and X. Geng,
"Inter-Domain Multicast Deployment using BIERv6", Work in
Progress, Internet-Draft, draft-geng-bier-ipv6-inter-
domain-02, 27 October 2020,
<https://www.ietf.org/archive/id/draft-geng-bier-ipv6-
inter-domain-02.txt>.
[I-D.ietf-bier-ping]
Kumar, N., Pignataro, C., Akiya, N., Zheng, L., Chen, M.,
and G. Mirsky, "BIER Ping and Trace", Work in Progress,
Internet-Draft, draft-ietf-bier-ping-07, 11 May 2020,
<https://www.ietf.org/archive/id/draft-ietf-bier-ping-
07.txt>.
Geng, et al. Expires 27 April 2023 [Page 15]
Internet-Draft MSR6 Traffic Engineering October 2022
[I-D.xie-bier-ipv6-mvpn]
Xie, J., McBride, M., Dhanaraj, S., Geng, L., and G.
Mishra, "Use of BIER IPv6 Encapsulation (BIERv6) for
Multicast VPN in IPv6 networks", Work in Progress,
Internet-Draft, draft-xie-bier-ipv6-mvpn-03, 10 October
2020, <https://www.ietf.org/archive/id/draft-xie-bier-
ipv6-mvpn-03.txt>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC4301] Kent, S. and K. Seo, "Security Architecture for the
Internet Protocol", RFC 4301, DOI 10.17487/RFC4301,
December 2005, <https://www.rfc-editor.org/info/rfc4301>.
[RFC4302] Kent, S., "IP Authentication Header", RFC 4302,
DOI 10.17487/RFC4302, December 2005,
<https://www.rfc-editor.org/info/rfc4302>.
[RFC4303] Kent, S., "IP Encapsulating Security Payload (ESP)",
RFC 4303, DOI 10.17487/RFC4303, December 2005,
<https://www.rfc-editor.org/info/rfc4303>.
[RFC5374] Weis, B., Gross, G., and D. Ignjatic, "Multicast
Extensions to the Security Architecture for the Internet
Protocol", RFC 5374, DOI 10.17487/RFC5374, November 2008,
<https://www.rfc-editor.org/info/rfc5374>.
[RFC7296] Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T.
Kivinen, "Internet Key Exchange Protocol Version 2
(IKEv2)", STD 79, RFC 7296, DOI 10.17487/RFC7296, October
2014, <https://www.rfc-editor.org/info/rfc7296>.
[RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", STD 86, RFC 8200,
DOI 10.17487/RFC8200, July 2017,
<https://www.rfc-editor.org/info/rfc8200>.
[RFC8279] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A.,
Przygienda, T., and S. Aldrin, "Multicast Using Bit Index
Explicit Replication (BIER)", RFC 8279,
DOI 10.17487/RFC8279, November 2017,
<https://www.rfc-editor.org/info/rfc8279>.
Geng, et al. Expires 27 April 2023 [Page 16]
Internet-Draft MSR6 Traffic Engineering October 2022
[RFC8296] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A.,
Tantsura, J., Aldrin, S., and I. Meilik, "Encapsulation
for Bit Index Explicit Replication (BIER) in MPLS and Non-
MPLS Networks", RFC 8296, DOI 10.17487/RFC8296, January
2018, <https://www.rfc-editor.org/info/rfc8296>.
[RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L.,
Decraene, B., Litkowski, S., and R. Shakir, "Segment
Routing Architecture", RFC 8402, DOI 10.17487/RFC8402,
July 2018, <https://www.rfc-editor.org/info/rfc8402>.
[RFC8754] Filsfils, C., Ed., Dukes, D., Ed., Previdi, S., Leddy, J.,
Matsushima, S., and D. Voyer, "IPv6 Segment Routing Header
(SRH)", RFC 8754, DOI 10.17487/RFC8754, March 2020,
<https://www.rfc-editor.org/info/rfc8754>.
[RFC8986] Filsfils, C., Ed., Camarillo, P., Ed., Leddy, J., Voyer,
D., Matsushima, S., and Z. Li, "Segment Routing over IPv6
(SRv6) Network Programming", RFC 8986,
DOI 10.17487/RFC8986, February 2021,
<https://www.rfc-editor.org/info/rfc8986>.
Authors' Addresses
Xuesong Geng
Huawei Technologies
Email: gengxuesong@huawei.com
Zhenbin Li
Huawei Technologies
Email: lizhenbin@huawei.com
Jingrong Xie
Huawei Technologies
Email: xiejingrong@huawei.com
Geng, et al. Expires 27 April 2023 [Page 17]
