Network Working Group X. Xu
Internet-Draft Huawei
Intended status: Standards Track A. Bashandy
Expires: April 1, 2018 Cisco
H. Assarpour
Broadcom
S. Ma
Juniper
W. Henderickx
Nokia
J. Tantsura
Individual
September 28, 2017
Unified Source Routing Instructions using MPLS Label Stack
draft-xu-mpls-unified-source-routing-instruction-04
Abstract
MPLS Segment Routing (SR-MPLS in short) is an MPLS data plane-based
source routing paradigm in which a sender of a packet is allowed to
partially or completely specify the route the packet takes through
the network by imposing stacked MPLS labels to the packet. SR-MPLS
could be leveraged to realize a unified source routing mechanism
across MPLS, IPv4 and IPv6 data planes by using an MPLS label stack
as a unified source routing instruction set while preserving backward
compatibility with SR-MPLS.
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
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on April 1, 2018.
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Copyright Notice
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . 3
4. Packet Forwarding Procedures . . . . . . . . . . . . . . . . 4
4.1. Forwarding Entry Construction . . . . . . . . . . . . . . 5
4.2. Packet Forwarding Procedures . . . . . . . . . . . . . . 6
5. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 9
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 10
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
8. Security Considerations . . . . . . . . . . . . . . . . . . . 10
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 10
9.1. Normative References . . . . . . . . . . . . . . . . . . 10
9.2. Informative References . . . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13
1. Introduction
MPLS Segment Routing (SR-MPLS in short)
[I-D.ietf-spring-segment-routing-mpls] is an MPLS data plane-based
source routing paradigm in which a sender of a packet is allowed to
partially or completely specify the route the packet takes through
the network by imposing stacked MPLS labels to the packet. SR-MPLS
could be leveraged to realize a unified source routing mechanism
across MPLS, IPv4 and IPv6 data planes by using an MPLS label stack
as a unified source routing instruction set while preserving backward
compatibility with SR-MPLS. More specifically, the source routing
instruction set information contained in a source routed packet could
be uniformly encoded as an MPLS label stack no matter the underlay is
IPv4, IPv6 or MPLS.
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Although the source routing instructions are encoded as MPLS labels,
this is a hardware convenience rather than an indication that the
whole MPLS protocol stack and in particular the MPLS control
protocols need to be deployed. Note that the complexity associated
with the whole MPLS protocol stack is largely due to the complex
control plane protocols.
Section 3 describes various use cases for the unified source routing
instruction mechanism and Section 4 describes a typical application
scenario and how the packet forwarding happens.
1.1. 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].
2. Terminology
This memo makes use of the terms defined in [RFC3031] and
[I-D.ietf-spring-segment-routing-mpls].
3. Use Cases
The unified source routing mechanism across IPv4, IPv6 and MPLS is
useful at least in the following use cases:
o Incremental deployment of the SR-MPLS technology
[I-D.xu-mpls-spring-islands-connection-over-ip]. Since there is
no need to run any other label distribution protocol (e.g., LDP,
see [I-D.ietf-spring-segment-routing-ldp-interop] for more
details.) on those non-SR-MPLS routers for incremental deployment
purposes, the network provisioning is greatly simplified, which is
one of the major claimed benefits of the SR-MPLS technology (i.e.,
running a single protocol).
o Overcome the load-balancing dilemma encountered by SR-MPLS. In
fact, this unified source routing mechanism is even useful in a
fully upgraded SR-MPLS network since the load-balancing dilemma
encountered by SR-MPLS [I-D.ietf-mpls-spring-entropy-label] due to
the maximum Readable Label-stack Depth (RLD) hardware limitation
[I-D.ietf-ospf-mpls-elc] [I-D.ietf-isis-mpls-elc]
[I-D.ietf-idr-bgp-ls-segment-routing-rld] and the Maximum SID
Depth (MSD) hardware limitation
[I-D.ietf-ospf-segment-routing-msd]
[I-D.ietf-isis-segment-routing-msd]
[I-D.ietf-idr-bgp-ls-segment-routing-msd] by using the MPLS-in-UDP
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encapsulation [RFC7510] where the source port of the UDP tunnel
header is used as an entropy field.
o A poor man's light-weight alternative to SRv6
[I-D.ietf-6man-segment-routing-header]. At least, it could be
deployed as an interim until full featured SRv6 is available on
more platforms. Since the Source Routing Header (SRH)
[I-D.ietf-6man-segment-routing-header] consisting of an ordered
list of 128-bit long IPv6 addresses is now replaced by an ordered
list of 32-bit long label entries (i.e., label stack), the
encapsulation overhead and forwarding performance issues
associated with SRv6 are eliminated.
o A new IPv4 source routing mechanism which has overcome the
security vulnerability issues associated with the traditional IPv4
source routing mechanism.
o Traffic Engineering scenarios where only a few routers (e.g., the
entry and exit nodes of each plane in the dual-plane network case
or the egress node in the Egress Peer Engineering (EPE) case) are
specified as segments of explicit paths. In this way, only a few
routers are required to support the SR-MPLS capability while all
the other routers just need to support IP forwarding capability,
which would significantly reduce the deployment cost of the SR-
MPLS technology.
o MPLS-based Service Function Chaining (SFC)
[I-D.xu-mpls-service-chaining]. Based on the unified source
routing mechanism as described in this document, only SFC-related
nodes including Service Function Forwarders (SFF), Service
Functions (SF) and classifiers are required to recognize the SFC
encapsulation header in the MPLS label stack form, while the
intermediate routers just need to support vanilla IP forwarding
(either IPv4 or IPv6). In other words, it undoubtedly complies
with the transport-independence requirement for the SFC
encapsulation header as listed in the SFC architecture document
[RFC7665].
4. Packet Forwarding Procedures
The primary objective of this document is to describe how SR-MPLS
capable routers and IP-only routers can seamlessly co-exist and
interoperate. This section describes the forwarding information base
(FIB) entry and the forwarding behavior that allow the deployment of
SR-MPLS when some routers are IPv4 only or IPv6 only. Note that OSPF
or ISIS is assumed to be enabled in the following examples as
described in Section 4.1 and 4.2, in fact, it's no doubt that BGP
could be used as a replacement.
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4.1. Forwarding Entry Construction
This sub-section describes the how to construct the forwarding
information base (FIB) entry on an SR-MPLS-capable router when some
or all of the next-hops along the shortest path towards a prefix-SID
are IPv4-only or IPv6-only routers. Consider the router "A"
receiving a labeled packet whose top label L(E) corresponds to the
prefix-SID is "SID(E)" of prefix "P(E)" advertised by the router "E".
Suppose the ith next-hop router "NHi" along the shortest path from
the router "A" towards the prefix-SID "SID(E)" is not SR-MPLS
capable. That is both routers "A" and "E" are SR-MPLS capable but
the next hop "NHi" along the shortest path from "A" to "E". The
following applies:
o It is assumed that the router "E" advertises the SR-Capabilities
sub-TLV as described in and
[I-D.ietf-ospf-segment-routing-extensions], which includes the
SRGB because router "E" is SR-MPLS capabile.
o The owning router "E" MUST advertise the encapsulation endpoint
and the tunnel type using [I-D.ietf-isis-encapsulation-cap] and/or
[I-D.ietf-ospf-encapsulation-cap] .
o If "A" and "E" are in different areas/levels, then
* The OSPF Tunnel Encapsulation TLV
[I-D.ietf-ospf-encapsulation-cap] and/or the ISIS Tunnel
Encapsulation sub-TLV [I-D.ietf-isis-encapsulation-cap] are
flooded domain-wide.
* The OSPF SID/label range TLV
[I-D.ietf-ospf-segment-routing-extensions] and the ISIS SR-
Capabilities Sub-TLV [I-D.ietf-isis-segment-routing-extensions]
are advertised domain-wide. This way router "A" knows the
characteristics of the owning router "E".
* When the owning router "E" is running ISIS and advertises the
prefix "P(E) ", the router "E" uses the extended reachability
TLV (TLVs 135, 235, 236, 237) and associates the IPv4/IPv6 and/
or IPv4/IPv6 source router ID sub-TLV(s) [RFC7794].
* When the owning router "E" is running OSPF and advertises the
prefix "P(E)", the router "E" uses the OSPFv2 Extended Prefix
Opaque LSA [RFC7684] and sets the flooding scope to AS-wide.
* When the owning router "E" is running ISIS and advertises the
ISIS capabilities TLV (TLV 242) [RFC7981], it must set the
"router-ID" field to a valid value or include IPV6 TE router-
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ID sub-TLV (TLV 12), or do both. The "S" bit (flooding scope)
of the ISIS capabilities TLV (TLV 242) MUST be set to "1" .
o Router "A" programs the FIB entry corresponding to the "SID(E)" as
follows:
* If NP (OSPF) or P (ISIS) flag is clear,
*
+ pop the outer label.
* If NP (OSPF) or P (ISIS) is set,
*
+ the outer label is SID(E) plus the lower bound of the SRGB
of "E".
* Encapsulate the packet according to the encapsulation
advertised in [I-D.ietf-isis-encapsulation-cap] or
[I-D.ietf-ospf-encapsulation-cap].
* Send the packet towards the next hop "NHi".
4.2. Packet Forwarding Procedures
+-----+ +-----+ +-----+ +-----+ +-----+
| A +-------+ B +-------+ C +--------+ D +--------+ H |
+-----+ +--+--+ +--+--+ +--+--+ +-----+
| | |
| | |
+--+--+ +--+--+ +--+--+
| E +-------+ F +--------+ G |
+-----+ +-----+ +-----+
+--------+
|IP(A->E)|
+--------+ +--------+
| L(G) | |IP(E->G)|
+--------+ +--------+ +--------+
| L(H) | | L(H) | |IP(G->H)|
+--------+ +--------+ +--------+
| Packet | ---> | Packet | ---> | Packet |
+--------+ +--------+ +--------+
Figure 1
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As shown in Figure 1, Assume Router A, E, G and H are SR-MPLS-capable
routers while the remaining are only capable of forwarding IP
packets. Router A, E, G and H advertise their Segment Routing
related information via IS-IS or OSPF. Now assume router A wants to
send a given IP or MPLS packet via an explicit path of {E->G->H},
router A would impose an MPLS label stack corresponding to that
explicit path on the received IP packet. Since there is no Label
Switching Path (LSP) towards router E, router A would replace the top
label indicating router E with an IP-based tunnel for MPLS (e.g.,
MPLS-over-UDP [RFC7510]) towards router E and then send it out. In
other words, router A would pop the top label and then encapsulate
the MPLS packet with an IP-based tunnel towards router E. When the
IP-encapsulated MPLS packet arrives at router E, router E would strip
the IP-based tunnel header and then process the decapsulated MPLS
packet accordingly. Since there is no LSP towards router G which is
indicated by the current top label of the decapsulated MPLS packet,
router E would replace the current top label with an IP-based tunnel
towards router G and send it out. When the packet arrives at router
G, router G would strip the IP-based tunnel header and then process
the decapsulated MPLS packet. Since there is no LSP towards router
H, router G would replace the current top label with an IP-based
tunnel towards router H. Now the packet encapsulated with the IP-
based tunnel towards router H is exactly the original packet that
router A had intended to send towards router H. If the packet is an
MPLS packet, router G could use any IP-based tunnel for MPLS (e.g.,
MPLS-over-UDP [RFC7510]). If the packet is an IP packet, router G
could use any IP tunnel for IP (e.g., IP-in-UDP
[I-D.xu-intarea-ip-in-udp]). That original IP or MPLS packet would
be forwarded towards router H via an IP-based tunnel. When the
encapsulated packet arrives at router H, router H would decapsulate
it into the original packet and then process it accordingly.
Note that in the above description, it's assumed that the label
associated with each prefix-SID advertised by the owner of the
prefix-SID is a Penultimate Hop Popping (PHP) label (e.g., the NP-
flag [I-D.ietf-ospf-segment-routing-extensions] associated with the
corresponding prefix SID is not set).
Figure 2 demostrates the packet walk in the case where the label
associated with each prefix-SID advertised by the owner of the
prefix-SID is not a Penultimate Hop Popping (PHP) label (e.g., the
NP-flag [I-D.ietf-ospf-segment-routing-extensions] associated with
the corresponding prefix SID is set).
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+-----+ +-----+ +-----+ +-----+ +-----+
| A +-------+ B +-------+ C +--------+ D +--------+ H |
+-----+ +--+--+ +--+--+ +--+--+ +-----+
| | |
| | |
+--+--+ +--+--+ +--+--+
| E +-------+ F +--------+ G |
+-----+ +-----+ +-----+
+--------+
|IP(A->E)|
+--------+ +--------+
| L(E) | |IP(E->G)|
+--------+ +--------+ +--------+
| L(G) | | L(G) | |IP(G->H)|
+--------+ +--------+ +--------+
| L(H) | | L(H) | | L(H) |
+--------+ +--------+ +--------+
| Packet | ---> | Packet | ---> | Packet |
+--------+ +--------+ +--------+
Figure 2
Although the above description is based on the use of prefix-SIDs,
the unified source routing instruction approach is actually
applicable to the use of adj-SIDs as well. For instance, when the
top label of a received MPLS packet indicates an given adj-SID and
the corresponding adjacent node to that adj-SID is not MPLS-capable,
the top label would be replaced by an IP-based tunnel towards that
adjacent node and then forwarded over the correponding link indicated
by that adj-SID.
When encapsulating an MPLS packet with an IP-based tunnel header
(e.g., a UDP header as per [RFC7510]), the corresponding entropy
field (i.e., the source port in the MPLS-in-UDP case) should be
filled with an entropy value that is generated by the encapsulator to
uniquely identify a flow. However, what constitutes a flow is
locally determined by the encapsulator. For instance, if the MPLS
label stack contains at least one entropy label and the encapsulator
is capable of reading that entropy label, the entropy label value
could be directly copied to the entropy field (e.g., the source port
of the UDP header). Otherwise, the encapsulator may have to perform
a hash on the whole label stack or the five-tuple of the MPLS payload
if the payload is determined as an IP packet. To avoid re-performing
hash on the whole packet when re-encapsulating the packet with an IP-
based tunnel header (e.g., a UDP tunnel header), especially when the
encapsulator could not obtain at least one entropy label due to some
reasons (e.g., 1) there is no EL at all in the label stack; 2) the
encapsulator couldn't recognize the ELI; 3) the encapsulator could
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not read the EL due to the RLD limit), it's RECOMMENDED that the
entropy value contained in the packet (e.g., the UDP source port
value) is kept when stripping the IP-based tunnel header (e.g., the
UDP tunnel header). As such, the entropy value could be directly
copied to the entropy field (e.g., the source port of the UDP tunnel
header) when re-encapsulating the packet with an IP-based tunnel
header (e.g., a UDP tunnel header). As such, the load-balancing
dilemma encountered by SR-MPLS as described in
[I-D.ietf-mpls-spring-entropy-label] due to the maximum Readable
Label-stack Depth (RLD) hardware limitation [I-D.ietf-ospf-mpls-elc]
[I-D.ietf-isis-mpls-elc] and the Maximum SID Depth (MSD) hardware
limitation [I-D.ietf-ospf-segment-routing-msd]
[I-D.ietf-isis-segment-routing-msd] is gone. That's the reason why
this unified source routing mechanism is even useful in a fully
upgraded SR-MPLS network environment.
5. Contributors
Clarence Filsfils
Cisco
Email: cfilsfil@cisco.com
Robert Raszuk
Bloomberg LP
Email: robert@raszuk.net
Uma Chunduri
Huawei
Email: uma.chunduri@gmail.com
Luis M. Contreras
Telefonica I+D
Email: luismiguel.contrerasmurillo@telefonica.com
Luay Jalil
Verizon
Email: luay.jalil@verizon.com
Gunter Van De Velde
Nokia
Email: gunter.van_de_velde@nokia.com
Tal Mizrahi
Marvell
Email: talmi@marvell.com
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6. Acknowledgements
Thanks Joel Halpern, Bruno Decraene, Loa Andersson and Stewart Bryant
for their insightful comments on this document.
7. IANA Considerations
No IANA action is required.
8. Security Considerations
TBD.
9. References
9.1. 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>.
9.2. Informative References
[]
Previdi, S., Filsfils, C., Raza, K., Leddy, J., Field, B.,
daniel.voyer@bell.ca, d., daniel.bernier@bell.ca, d.,
Matsushima, S., Leung, I., Linkova, J., Aries, E., Kosugi,
T., Vyncke, E., Lebrun, D., Steinberg, D., and R. Raszuk,
"IPv6 Segment Routing Header (SRH)", draft-ietf-6man-
segment-routing-header-07 (work in progress), July 2017.
[I-D.ietf-idr-bgp-ls-segment-routing-msd]
Tantsura, J., Chunduri, U., Mirsky, G., and S. Sivabalan,
"Signaling Maximum SID Depth using Border Gateway Protocol
Link-State", draft-ietf-idr-bgp-ls-segment-routing-msd-00
(work in progress), July 2017.
[I-D.ietf-idr-bgp-ls-segment-routing-rld]
Velde, G., Henderickx, W., Bocci, M., and K. Patel,
"Signalling ERLD using BGP-LS", draft-ietf-idr-bgp-ls-
segment-routing-rld-00 (work in progress), July 2017.
[I-D.ietf-isis-encapsulation-cap]
Xu, X., Decraene, B., Raszuk, R., Chunduri, U., Contreras,
L., and L. Jalil, "Advertising Tunnelling Capability in
IS-IS", draft-ietf-isis-encapsulation-cap-01 (work in
progress), April 2017.
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[I-D.ietf-isis-mpls-elc]
Xu, X., Kini, S., Sivabalan, S., Filsfils, C., and S.
Litkowski, "Signaling Entropy Label Capability Using IS-
IS", draft-ietf-isis-mpls-elc-02 (work in progress),
October 2016.
[I-D.ietf-isis-segment-routing-extensions]
Previdi, S., Filsfils, C., Bashandy, A., Gredler, H.,
Litkowski, S., Decraene, B., and j. jefftant@gmail.com,
"IS-IS Extensions for Segment Routing", draft-ietf-isis-
segment-routing-extensions-13 (work in progress), June
2017.
[I-D.ietf-isis-segment-routing-msd]
Tantsura, J., Chunduri, U., Aldrin, S., and L. Ginsberg,
"Signaling MSD (Maximum SID Depth) using IS-IS", draft-
ietf-isis-segment-routing-msd-04 (work in progress), June
2017.
[I-D.ietf-mpls-spring-entropy-label]
Kini, S., Kompella, K., Sivabalan, S., Litkowski, S.,
Shakir, R., and j. jefftant@gmail.com, "Entropy label for
SPRING tunnels", draft-ietf-mpls-spring-entropy-label-06
(work in progress), May 2017.
[I-D.ietf-ospf-encapsulation-cap]
Xu, X., Decraene, B., Raszuk, R., Contreras, L., and L.
Jalil, "The Tunnel Encapsulations OSPF Router
Information", draft-ietf-ospf-encapsulation-cap-08 (work
in progress), September 2017.
[I-D.ietf-ospf-mpls-elc]
Xu, X., Kini, S., Sivabalan, S., Filsfils, C., and S.
Litkowski, "Signaling Entropy Label Capability Using
OSPF", draft-ietf-ospf-mpls-elc-04 (work in progress),
November 2016.
[I-D.ietf-ospf-segment-routing-extensions]
Psenak, P., Previdi, S., Filsfils, C., Gredler, H.,
Shakir, R., Henderickx, W., and J. Tantsura, "OSPF
Extensions for Segment Routing", draft-ietf-ospf-segment-
routing-extensions-19 (work in progress), August 2017.
[I-D.ietf-ospf-segment-routing-msd]
Tantsura, J., Chunduri, U., Aldrin, S., and P. Psenak,
"Signaling MSD (Maximum SID Depth) using OSPF", draft-
ietf-ospf-segment-routing-msd-05 (work in progress), June
2017.
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[I-D.ietf-spring-segment-routing-ldp-interop]
Filsfils, C., Previdi, S., Bashandy, A., Decraene, B., and
S. Litkowski, "Segment Routing interworking with LDP",
draft-ietf-spring-segment-routing-ldp-interop-08 (work in
progress), June 2017.
[I-D.ietf-spring-segment-routing-mpls]
Filsfils, C., Previdi, S., Bashandy, A., Decraene, B.,
Litkowski, S., and R. Shakir, "Segment Routing with MPLS
data plane", draft-ietf-spring-segment-routing-mpls-10
(work in progress), June 2017.
[I-D.xu-intarea-ip-in-udp]
Xu, X., Lee, Y., and F. Yongbing, "Encapsulating IP in
UDP", draft-xu-intarea-ip-in-udp-04 (work in progress),
December 2016.
[I-D.xu-mpls-service-chaining]
Xu, X., Bryant, S., Assarpour, H., Shah, H., Contreras,
L., daniel.bernier@bell.ca, d., jefftant@gmail.com, j.,
Ma, S., and M. Vigoureux, "Service Chaining using Unified
Source Routing Instructions", draft-xu-mpls-service-
chaining-03 (work in progress), June 2017.
[I-D.xu-mpls-spring-islands-connection-over-ip]
Xu, X., Raszuk, R., Chunduri, U., Contreras, L., and L.
Jalil, "Connecting MPLS-SPRING Islands over IP Networks",
draft-xu-mpls-spring-islands-connection-over-ip-00 (work
in progress), October 2016.
[RFC2784] Farinacci, D., Li, T., Hanks, S., Meyer, D., and P.
Traina, "Generic Routing Encapsulation (GRE)", RFC 2784,
DOI 10.17487/RFC2784, March 2000,
<https://www.rfc-editor.org/info/rfc2784>.
[RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol
Label Switching Architecture", RFC 3031,
DOI 10.17487/RFC3031, January 2001,
<https://www.rfc-editor.org/info/rfc3031>.
[RFC4817] Townsley, M., Pignataro, C., Wainner, S., Seely, T., and
J. Young, "Encapsulation of MPLS over Layer 2 Tunneling
Protocol Version 3", RFC 4817, DOI 10.17487/RFC4817, March
2007, <https://www.rfc-editor.org/info/rfc4817>.
Xu, et al. Expires April 1, 2018 [Page 12]
Internet-Draft USR September 2017
[RFC7510] Xu, X., Sheth, N., Yong, L., Callon, R., and D. Black,
"Encapsulating MPLS in UDP", RFC 7510,
DOI 10.17487/RFC7510, April 2015,
<https://www.rfc-editor.org/info/rfc7510>.
[RFC7665] Halpern, J., Ed. and C. Pignataro, Ed., "Service Function
Chaining (SFC) Architecture", RFC 7665,
DOI 10.17487/RFC7665, October 2015,
<https://www.rfc-editor.org/info/rfc7665>.
[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>.
[RFC7794] Ginsberg, L., Ed., Decraene, B., Previdi, S., Xu, X., and
U. Chunduri, "IS-IS Prefix Attributes for Extended IPv4
and IPv6 Reachability", RFC 7794, DOI 10.17487/RFC7794,
March 2016, <https://www.rfc-editor.org/info/rfc7794>.
[RFC7981] Ginsberg, L., Previdi, S., and M. Chen, "IS-IS Extensions
for Advertising Router Information", RFC 7981,
DOI 10.17487/RFC7981, October 2016,
<https://www.rfc-editor.org/info/rfc7981>.
Authors' Addresses
Xiaohu Xu
Huawei
Email: xuxiaohu@huawei.com
Ahmed Bashandy
Cisco
Email: bashandy@cisco.com
Hamid Assarpour
Broadcom
Email: hamid.assarpour@broadcom.com
Xu, et al. Expires April 1, 2018 [Page 13]
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Shaowen Ma
Juniper
Email: mashao@juniper.net
Wim Henderickx
Nokia
Email: wim.henderickx@nokia.com
Jeff Tantsura
Individual
Email: jefftant@gmail.com
Xu, et al. Expires April 1, 2018 [Page 14]
