Internet DRAFT - draft-hc-lsr-sr-proxy-fw
draft-hc-lsr-sr-proxy-fw
Network Working Group Z. Hu
Internet-Draft Huawei Technologies
Intended status: Standards Track H. Chen
Expires: 28 February 2024 Futurewei
J. Yao
Huawei Technologies
C. Bowers
Juniper Networks
Y. Zhu
China Telecom
Y. Liu
China Mobile
27 August 2023
LSR for SR Proxy Forwarding
draft-hc-lsr-sr-proxy-fw-03
Abstract
This document describes extensions to OSPF and IS-IS to support SR
proxy forwarding mechanism for fast protecting the failure of a node
with segments on a SR-TE path. The segments of the node include
adjacency, node or binding segments.
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].
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
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
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 28 February 2024.
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Copyright Notice
Copyright (c) 2023 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
and restrictions with respect to this document. Code Components
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provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. IGP Extensions/Re-uses for Proxy Forwarding . . . . . . . . . 3
2.1. OSPF Extensions/Re-uses . . . . . . . . . . . . . . . . . 3
2.1.1. Advertising Binding Segment . . . . . . . . . . . . . 3
2.1.2. Advertising Proxy Forwarding . . . . . . . . . . . . 6
2.2. IS-IS Extensions/Re-uses . . . . . . . . . . . . . . . . 7
2.2.1. Advertising Binding Segment . . . . . . . . . . . . . 7
2.2.2. Advertising Proxy Forwarding . . . . . . . . . . . . 8
3. Security Considerations . . . . . . . . . . . . . . . . . . . 9
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
4.1. OSPFv2 . . . . . . . . . . . . . . . . . . . . . . . . . 9
4.2. OSPFv3 . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.3. IS-IS . . . . . . . . . . . . . . . . . . . . . . . . . . 11
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 12
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 12
6.1. Normative References . . . . . . . . . . . . . . . . . . 12
6.2. Informative References . . . . . . . . . . . . . . . . . 13
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13
1. Introduction
[I-D.hu-spring-segment-routing-proxy-forwarding] describes a SR proxy
forwarding for protection. Each neighbor of a possible failed node
advertises its SR proxy forwarding capability when it has the
capability. This capability indicates that the neighbor (the Proxy
Forwarder) will forward traffic on behalf of the failed node. A
router receiving the capability from the neighbors of a failed node
will send traffic using the node-SID of the failed node to the
nearest Proxy Forwarder after the IGP converges on the failure.
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Once the affected traffic reaches a Proxy Forwarder, it sends the
traffic on the post-failure shortest path to the node immediately
following the failed node in the segment list.
For a binding segment of a possible failed node, the node advertises
the information about the binding segment, including the binding SID
and the list of SIDs associated with the binding SID, to its direct
neighbors only. Note that the information is not advertised in the
network domain.
After the node fails and the IGP converges on the failure, the
traffic with the binding SID of the failed node will reach its
neighbor having SR Proxy Forwarding capability. Once receiving the
traffic, the neighbor swaps the binding SID with the list of SIDs/
segments associated with the binding SID and sends the traffic along
the post-failure shortest path to the first node in the segment list.
2. IGP Extensions/Re-uses for Proxy Forwarding
This section defines IGP extensions for advertising the information
about each binding segment (including its binding SID and the list of
SIDs/segments associated with the binding SID) of a node to its
direct neighbors. It describes IGP re-uses/extensions for
advertising the SR proxy forwarding capability of a node in a network
domain.
2.1. OSPF Extensions/Re-uses
2.1.1. Advertising Binding Segment
For a binding segment (or binding for short) on a node A, which
consists of a binding SID and a list of segments, node A advertises
an LSA containing the binding (i.e., the binding SID and the list of
the segments). The LSA is advertised only to each of the node A's
neighboring nodes. For OSPFv2, the LSA is a opaque LSA of LS type 9
(i.e., a link local scope LSA).
A binding segment is represented by binding segment TLV of the format
as shown in Figure 1.
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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 (TBD2) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved |BindingSID Type| SIDs Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Binding SID Sub-TLV/value ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ SID Sub-TLVs/values ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: OSPF Binding Segment TLV
It comprises a binding SID and a list of segments (SIDs). The fields
of this TLV are defined as follows:
Type: 2 octets, its value (TBD2) is to be assigned by IANA.
Length: 2 octets, its value is (4 + length of Sub-TLVs/values).
Binding SID Type (BT): 1 octet indicates whether the binding SID is
represented by a Sub-TLV or a value included in the TLV. For the
binding SID represented by a value, it indicates the type of binding
SID. The following BT values are defined:
o BT = 0: The binding SID is represented by a Sub-TLV (i.e., Binding
SID Sub-TLV) in the TLV. A binding SID Sub-TLV is a SID/Label Sub-
TLV defined in [RFC8665]. BT != 0 indicates that the binding SID is
represented by a value.
o BT = 1: The binding SID value is a label, which is represented by
the 20 rightmost bits. The length of the value is 3 octets.
o BT = 2: The binding SID value is a 32-bit SID. The length of the
value is 4 octets.
SIDs Type (ST): 1 octet indicates whether the list of segments (SIDs)
are represented by Sub-TLVs or values included in the TLV. For the
SIDs represented by values, it indicates the type of SIDs. The
following ST values are defined:
o ST = 0: The SIDs are represented by Sub-TLVs (i.e., SID Sub-TLVs)
in the TLV. A SID Sub-TLV is an Adj-SID Sub-TLV, a Prefix-SID Sub-
TLV or a SID/Label Sub-TLV defined in [RFC8665]. ST != 0 indicates
that the SIDs are represented by values.
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o ST = 1: Each of the SID values is a label, which is represented by
the 20 rightmost bits. The length of the value is 3 octets.
o ST = 2: Each of the SID values is a 32-bit SID. The length of the
value is 4 octets.
The opaque LSA of LS Type 9 containing the binding segment (i.e., the
binding SID and the list of the segments) has the format as shown in
Figure 2. It may have Opaque Type of x (the exact type is to be
assigned by IANA) for Binding Segment Opaque LSA.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LS age | Options | LS Type (9) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opaque Type(x)| Opaque ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Advertising Router |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LS sequence number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LS checksum | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
: Binding Segment TLVs :
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: OSPFv2 Binding Segment Opaque LSA
For every binding on a node A, the LSA originated by A contains a
binding segment TLV for it.
For node A running OSPFv3, it originates a link-local scoping LSA of
a new LSA function code (TBD3) containing binding segment TLVs for
the bindings on it. The format of the LSA is illustrated in
Figure 3.
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LS age |0|0|0| BS-LSA (TBD3) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Link State ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Advertising Router |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LS Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LS checksum | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
: Binding Segment TLVs :
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: OSPFv3 Binding Segment Opaque LSA
The U-bit is set to 0, and the scope is set to 00 for link-local
scoping.
2.1.2. Advertising Proxy Forwarding
When a node P has the capability to do a SR proxy forwarding for its
neighboring nodes for protecting the failures of these nodes, P
advertises its capability for these nodes. The mirror SID
[RFC8402][RFC8667] for a node N (Neighbor of P) advertised by P
indicates the capability of P for N.
Alternatively, P advertises its capability in its router information
opaque LSA with Router Functional Capabilities TLV [RFC7770]. One
bit (called PF bit) in the Functional Capabilities field of the TLV
is used to indicate node P's capability. When this bit is set to one
by node P, it indicates that node P is capable of doing a SR proxy
forwarding for its neighboring nodes.
For a node X in the network, it learns the prefix/node SID of node N,
which is originated and advertised by node N. It creates a proxy
prefix/node SID of node N for node P if node P is capable of doing SR
proxy forwarding for node N. The proxy prefix/node SID of node N for
node P is a copy of the prefix/node SID of node N originated by node
N, but stored under (or say, associated with) node P. The route to
the proxy prefix/node SID is through proxy forwarding capable nodes.
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In normal operations, node X prefers to use the prefix/node SID of
node N. When node N fails, node X prefers to use the proxy prefix/
node SID of node N. Thus node X will forward the traffic targeting
to the prefix/node SID of node N to node P when node N fails, and
node P will do a SR proxy forwarding for node N and forward the
traffic towards its final destination without going through node N.
Note that the behaviors of normal IP forwarding and routing
convergences in a network are not changed at all by the SR proxy
forwarding. For example, the next hop used by BGP is an IP address
(or prefix). The IGP and BGP converge in normal ways for changes in
the network. The packet with its IP destination to this next hop is
forwarded according to the IP forwarding table (FIB) derived from IGP
and BGP routes.
2.2. IS-IS Extensions/Re-uses
2.2.1. Advertising Binding Segment
For supporting binding SID proxy forwarding, a new IS-IS TLV, called
Binding Segment TLV, is defined. It contains a binding SID and a
list of segments (SIDs). This TLV is advertised in Circuit Scoped
Link State PDUs (CS-LSP) [RFC7356]. Its format is shown in Figure 4.
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 |BindingSID Type| SIDs Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Binding SID value/Sub-TLV ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ SID values/Sub-TLVs ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: IS-IS Binding Segment TLV
The fields of this TLV are defined as follows:
Type: 1 octet Suggested value 152 (to be assigned by IANA)
Length: 1 octet (2 + length of Sub-TLVs/values).
The other fields are the same as those in Figure 1.
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2.2.2. Advertising Proxy Forwarding
When a node P has the capability to do a SR proxy forwarding for its
neighboring nodes, P advertises its capability in its LSP with a
Router Capability TLV of Type 242 including a SR capabilities sub-TLV
of sub-Type 2.
One bit (called PF bit) in the Flags field of the SR capabilities
sub-TLV is defined to indicate node P's capability. When this bit is
set to one by node P, it indicates that node P is capable of doing a
SR proxy forwarding for its neighboring nodes.
If node P can not do a SR proxy forwarding for all its neighboring
nodes, but for some of them, then it advertises the node SID of each
of the nodes as a proxy node SID, indicating that it is able to do
proxy forwarding for the node SID.
The IS-IS SID/Label Binding TLV (suggested value 149) is defined in
[RFC8667]. A Proxy Forwarder uses the SID/Label Binding TLV to
advertise the node SID of its neighboring node. The Flags field of
the SID/Label Binding TLV is extended to include a P flag as shown in
Figure 5. The prefix/node SID in prefix/node SID Sub-TLV included in
SID/Label Binding TLV is identified as a proxy forwarding prefix/node
SID.
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 | Flags | RESERVED |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Range | Prefix Length | Prefix |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// Prefix (continued, variable) //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SubTLVs (variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|F|M|S|D|A|P| |
+-+-+-+-+-+-+-+-+
Flags
Figure 5: SID/Label Binding TLV
Where:
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P-Flag: Proxy forwarding flag. If set, this prefix/node SID is
advertised by the proxy node. This TLV is used to announce that the
node has the ability to proxy forward the prefix/node SID.
When the P-flag is set in the SID/Label Binding TLV, the following
usage rules apply.
The Range, Prefix Length and Prefix field are not used. They should
be set to zero on transmission and ignored on receipt.
SID/Label Binding TLV contains a number of prefix/node SID Sub-TLVs.
The TLV advertised by a proxy forwarding node P contains prefix/node
SID Sub-TLVs for the node SIDs of P's neighbor nodes. Each of the
Sub-TLVs is a prefix/node SID Sub-TLV defined in [RFC8667]. From the
SID in a prefix/node SID Sub-TLV advertised by the Proxy Forwarding
node, its prefix can be obtained through matching corresponding
prefix/node SID advertised by the neighbor/protected node using
TLV-135 (or 235, 236, or 237) together with the prefix/node SID Sub-
TLV.
3. Security Considerations
The extensions to OSPF and IS-IS described in this document result in
two types of behaviors in data plane when a node in a network fails.
One is that for a node, which is a upstream (except for the direct
upstream) node of the failed node along a SR-TE path, it continues to
send the traffic to the failed node along the SR-TE path for an
extended period of time. The other is that for a node, which is the
direct upstream node of the failed node, it fast re-routes the
traffic around the failed node to the direct downstream node of the
failed node along the SR-TE path. These behaviors are internal to a
network and should not cause extra security issues.
4. IANA Considerations
4.1. OSPFv2
Under Subregistry Name "OSPF Router Functional Capability Bits"
within the "Open Shortest Path First v2 (OSPFv2) Parameters"
[RFC7770], IANA is requested to assign one bit for Proxy Forwarding
Capability as follows:
+============+==================+===================+
| Bit number | Capability Name | Reference |
+============+==================+===================+
| 31 | Proxy Forwarding | This document |
+------------+------------------+-------------------+
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Under Registry Name "OSPFv2 Extended Prefix Opaque LSA TLVs"
[RFC7684], IANA is requested to assign one new TLV value for OSPF
Proxy Node SIDs as follows:
+============+=====================+================+
| TLV Value | TLV Name | Reference |
+============+=====================+================+
| 2 | Proxy Node SIDs TLV | This document |
+------------+---------------------+----------------+
Under Registry Name "Opaque Link-State Advertisements (LSA) Option
Types" [RFC5250], IANA is requested to assign new Opaque Type
registry values for Binding Segment LSA as follows:
+================+==================+================+
| Registry Value | Opaque Type | Reference |
+================+==================+================+
| 10 | Binding Segment | This document |
+----------------+------------------+----------------+
IANA is requested to create and maintain new registries:
o OSPFv2 Binding Segment Opaque LSA TLVs
Initial values for the registry are given below. The future
assignments are to be made through IETF Review [RFC5226].
Value TLV Name Definition
----- ----------------------- ----------
0 Reserved
1 Binding Segment TLV This Document
2-32767 Unassigned
32768-65535 Reserved
4.2. OSPFv3
Under Registry Name "OSPFv3 LSA Function Codes", IANA is requested to
assign new registry values for Binding Segment LSA as follows:
+========+========================+================+
| Value | LSA Function Code Name | Reference |
+========+========================+================+
| 16 | Binding Segment LSA | This document |
+--------+------------------------+----------------+
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IANA is requested to create and maintain new registries:
o OSPFv3 Binding Segment LSA TLVs
Initial values for the registry are given below. The future
assignments are to be made through IETF Review [RFC5226].
Value TLV Name Definition
----- ----------------------- ----------
0 Reserved
1 Binding Segment TLV This Document
2-32767 Unassigned
32768-65535 Reserved
4.3. IS-IS
Under Registration "Segment Routing Capability" in the "sub-TLVs for
TLV 242" registry [RFC8667], IANA is requested to assign one bit flag
for Proxy Forwarding Capability as follows:
+============+=======================+===============+
| Bit number | Capability Name | Reference |
+============+=======================+===============+
| 2 | Proxy Forwarding (PF) | This document |
+------------+-----------------------+---------------+
Under Registration "Segment Identifier/Label Binding TLV 149"
[RFC8667], IANA is requested to assign one bit P-Flag as follows:
+============+=================+===============+
| Bit number | Flag Name | Reference |
+============+=================+===============+
| 5 | P-Flag | This document |
+------------+-----------------+---------------+
Under Registry Name: IS-IS TLV Codepoints, IANA is requested to
assign one new TLV value for IS-IS Binding Segment as follows:
+========+======================+===============+
| Value | TLV Name | Reference |
+========+======================+===============+
| 152 | Binding Segment TLV | This Document |
+--------+----------------------+---------------+
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5. Acknowledgements
The authors would like to thank Peter Psenak, Acee Lindem, Les
Ginsberg, Bruno Decraene and Jeff Tantsura for their comments to this
work.
6. References
6.1. Normative References
[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>.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", RFC 5226,
DOI 10.17487/RFC5226, May 2008,
<https://www.rfc-editor.org/info/rfc5226>.
[RFC5250] Berger, L., Bryskin, I., Zinin, A., and R. Coltun, "The
OSPF Opaque LSA Option", RFC 5250, DOI 10.17487/RFC5250,
July 2008, <https://www.rfc-editor.org/info/rfc5250>.
[RFC7356] Ginsberg, L., Previdi, S., and Y. Yang, "IS-IS Flooding
Scope Link State PDUs (LSPs)", RFC 7356,
DOI 10.17487/RFC7356, September 2014,
<https://www.rfc-editor.org/info/rfc7356>.
[RFC7684] Psenak, P., Gredler, H., Shakir, R., Henderickx, W.,
Tantsura, J., and A. Lindem, "OSPFv2 Prefix/Link Attribute
Advertisement", RFC 7684, DOI 10.17487/RFC7684, November
2015, <https://www.rfc-editor.org/info/rfc7684>.
[RFC7770] Lindem, A., Ed., Shen, N., Vasseur, JP., Aggarwal, R., and
S. Shaffer, "Extensions to OSPF for Advertising Optional
Router Capabilities", RFC 7770, DOI 10.17487/RFC7770,
February 2016, <https://www.rfc-editor.org/info/rfc7770>.
[RFC8665] Psenak, P., Ed., Previdi, S., Ed., Filsfils, C., Gredler,
H., Shakir, R., Henderickx, W., and J. Tantsura, "OSPF
Extensions for Segment Routing", RFC 8665,
DOI 10.17487/RFC8665, December 2019,
<https://www.rfc-editor.org/info/rfc8665>.
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[RFC8667] Previdi, S., Ed., Ginsberg, L., Ed., Filsfils, C.,
Bashandy, A., Gredler, H., and B. Decraene, "IS-IS
Extensions for Segment Routing", RFC 8667,
DOI 10.17487/RFC8667, December 2019,
<https://www.rfc-editor.org/info/rfc8667>.
6.2. Informative References
[I-D.hu-spring-segment-routing-proxy-forwarding]
Hu, Z., Chen, H., Yao, J., Bowers, C., Zhu, Y., and Y.
Liu, "SR-TE Path Midpoint Restoration", Work in Progress,
Internet-Draft, draft-hu-spring-segment-routing-proxy-
forwarding-24, 21 August 2023,
<https://datatracker.ietf.org/doc/html/draft-hu-spring-
segment-routing-proxy-forwarding-24>.
[I-D.ietf-spring-segment-routing-policy]
Filsfils, C., Talaulikar, K., Voyer, D., Bogdanov, A., and
P. Mattes, "Segment Routing Policy Architecture", Work in
Progress, Internet-Draft, draft-ietf-spring-segment-
routing-policy-22, 22 March 2022,
<https://datatracker.ietf.org/doc/html/draft-ietf-spring-
segment-routing-policy-22>.
[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>.
Authors' Addresses
Zhibo Hu
Huawei Technologies
Huawei Bld., No.156 Beiqing Rd.
Beijing
100095
China
Email: huzhibo@huawei.com
Huaimo Chen
Futurewei
Boston, MA,
United States of America
Email: Huaimo.chen@futurewei.com
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Junda Yao
Huawei Technologies
Huawei Bld., No.156 Beiqing Rd.
Beijing
100095
China
Email: yaojunda@huawei.com
Chris Bowers
Juniper Networks
1194 N. Mathilda Ave.
Sunnyvale, CA, 94089
United States of America
Email: cbowers@juniper.net
Yongqing
China Telecom
109, West Zhongshan Road, Tianhe District
Guangzhou
510000
China
Email: zhuyq8@chinatelecom.cn
Yisong
China Mobile
510000
China
Email: liuyisong@chinamobile.com
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