draft-ietf-ospf-segment-routing-msd-15.txt   draft-ietf-ospf-segment-routing-msd-16.txt 
OSPF Working Group J. Tantsura OSPF Working Group J. Tantsura
Internet-Draft Nuage Networks Internet-Draft Nuage Networks
Intended status: Standards Track U. Chunduri Intended status: Standards Track U. Chunduri
Expires: January 25, 2019 Huawei Technologies Expires: February 20, 2019 Huawei Technologies
S. Aldrin S. Aldrin
Google, Inc Google, Inc
P. Psenak P. Psenak
Cisco Systems Cisco Systems
July 24, 2018 August 19, 2018
Signaling MSD (Maximum SID Depth) using OSPF Signaling MSD (Maximum SID Depth) using OSPF
draft-ietf-ospf-segment-routing-msd-15 draft-ietf-ospf-segment-routing-msd-16
Abstract Abstract
This document defines a way for an OSPF Router to advertise multiple This document defines a way for an Open Shortest Path First (OSPF)
types of supported Maximum SID Depths (MSDs) at node and/or link Router to advertise multiple types of supported Maximum SID Depths
granularity. Such advertisements allow entities (e.g., centralized (MSDs) at node and/or link granularity. Such advertisements allow
controllers) to determine whether a particular SID stack can be entities (e.g., centralized controllers) to determine whether a
supported in a given network. This document defines only one type of particular SID stack can be supported in a given network. This
MSD, but defines an encoding that can support other MSD types. Here document defines only one type of MSD, but defines an encoding that
the term OSPF means both OSPFv2 and OSPFv3. can support other MSD types. Here the term OSPF means both OSPFv2
and OSPFv3.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
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This Internet-Draft will expire on January 25, 2019. This Internet-Draft will expire on February 20, 2019.
Copyright Notice Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the Copyright (c) 2018 IETF Trust and the persons identified as the
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Conventions used in this document . . . . . . . . . . . . 3 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
1.1.1. Terminology . . . . . . . . . . . . . . . . . . . . . 3
1.2. Requirements Language . . . . . . . . . . . . . . . . . . 4 1.2. Requirements Language . . . . . . . . . . . . . . . . . . 4
2. Node MSD Advertisement . . . . . . . . . . . . . . . . . . . 4 2. Node MSD Advertisement . . . . . . . . . . . . . . . . . . . 4
3. Link MSD sub-TLV . . . . . . . . . . . . . . . . . . . . . . 5 3. Link MSD sub-TLV . . . . . . . . . . . . . . . . . . . . . . 5
4. Using Node and Link MSD Advertisements . . . . . . . . . . . 6 4. Using Node and Link MSD Advertisements . . . . . . . . . . . 6
5. Base MPLS Imposition MSD . . . . . . . . . . . . . . . . . . 6 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7 6. Security Considerations . . . . . . . . . . . . . . . . . . . 7
7. Security Considerations . . . . . . . . . . . . . . . . . . . 7 7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 7
8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 7 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 7 9.1. Normative References . . . . . . . . . . . . . . . . . . 7
10.1. Normative References . . . . . . . . . . . . . . . . . . 8 9.2. Informative References . . . . . . . . . . . . . . . . . 8
10.2. Informative References . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction 1. Introduction
When Segment Routing(SR) paths are computed by a centralized When Segment Routing (SR) paths are computed by a centralized
controller, it is critical that the controller learns the Maximum SID controller, it is critical that the controller learns the Maximum SID
Depth(MSD) that can be imposed at each node/link on a given SR path Depth (MSD) that can be imposed at each node/link on a given SR path
to insure that the SID stack depth of a computed path doesn't exceed to insure that the SID stack depth of a computed path doesn't exceed
the number of SIDs the node is capable of imposing. the number of SIDs the node is capable of imposing.
The PCEP SR extensions draft [I-D.ietf-pce-segment-routing] signals Path Computation Element Protocol(PCEP) SR draft
MSD in SR PCE Capability TLV and METRIC Object. However, if PCEP is [I-D.ietf-pce-segment-routing] signals MSD in SR Path Computation
not supported/configured on the head-end of an SR tunnel or a Element Capability TLV and METRIC Object. However, if PCEP is not
Binding-SID anchor node and controller do not participate in IGP supported/configured on the head-end of an SR tunnel or a Binding-SID
routing, it has no way to learn the MSD of nodes and links. BGP-LS anchor node and controller does not participate in IGP routing, it
has no way to learn the MSD of nodes and links. BGP-LS (Distribution
of Link-State and TE Information using Border Gateway Protocol)
[RFC7752] defines a way to expose topology and associated attributes [RFC7752] defines a way to expose topology and associated attributes
and capabilities of the nodes in that topology to a centralized and capabilities of the nodes in that topology to a centralized
controller. MSD signaling by BGP-LS has been defined in controller. MSD signaling by BGP-LS has been defined in
[I-D.ietf-idr-bgp-ls-segment-routing-msd]. Typically, BGP-LS is [I-D.ietf-idr-bgp-ls-segment-routing-msd]. Typically, BGP-LS is
configured on a small number of nodes that do not necessarily act as configured on a small number of nodes that do not necessarily act as
head-ends. In order for BGP-LS to signal MSD for all the nodes and head-ends. In order for BGP-LS to signal MSD for all the nodes and
links in the network MSD is relevant, MSD capabilites should be links in the network MSD is relevant, MSD capabilities should be
advertised by every OSPF router in the network. advertised by every OSPF router in the network.
Other types of MSD are known to be useful. For example, Other types of MSD are known to be useful. For example,
[I-D.ietf-ospf-mpls-elc] defines Readable Label Depth Capability [I-D.ietf-ospf-mpls-elc] defines Readable Label Depth Capability
(RLDC) that is used by a head-end to insert an Entropy Label (EL) at (RLDC) that is used by a head-end to insert an Entropy Label (EL) at
a depth that can be read by transit nodes. a depth that can be read by transit nodes.
This document defines an extension to OSPF used to advertise one or This document defines an extension to OSPF used to advertise one or
more types of MSD at node and/or link granularity. It also defines more types of MSD at node and/or link granularity. It also defines
the Base MPLS Imposition MSD type. In the future it is expected, the Base MPLS Imposition MSD type. In the future it is expected,
that new MSD types will be defined to signal additional capabilities that new MSD types will be defined to signal additional capabilities
e.g., entropy labels, SIDs that can be imposed through recirculation, e.g., entropy labels, SIDs that can be imposed through recirculation,
or SIDs associated with another dataplane e.g., IPv6. Although MSD or SIDs associated with another dataplane e.g., IPv6. Although MSD
advertisements are associated with Segment Routing, the advertisements are associated with Segment Routing, the
advertisements MAY be present even if Segment Routing itself is not advertisements MAY be present even if Segment Routing itself is not
enabled. enabled.
1.1. Conventions used in this document 1.1. Terminology
1.1.1. Terminology
This memo makes use of the terms defined in [RFC7770] This memo makes use of the terms defined in [RFC7770]
BGP-LS: Distribution of Link-State and TE Information using Border BGP-LS: Distribution of Link-State and TE Information using Border
Gateway Protocol Gateway Protocol
BMI: Base MPLS Imposition is the number of MPLS labels that can be BMI: Base MPLS Imposition is the number of MPLS labels that can be
imposed inclusive of all service/transport/special labels imposed inclusive of all service/transport/special labels
OSPF: Open Shortest Path First OSPF: Open Shortest Path First
skipping to change at page 4, line 15 skipping to change at page 4, line 15
1.2. Requirements Language 1.2. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
2. Node MSD Advertisement 2. Node MSD Advertisement
The node MSD TLV within the body of the OSPF RI Opaque LSA is defined The node MSD TLV within the body of the OSPF RI Opaque LSA [RFC7770]
to carry the provisioned SID depth of the router originating the RI is defined to carry the provisioned SID depth of the router
LSA. Node MSD is the smallest MSD supported by the node on the set originating the RI LSA. Node MSD is the smallest MSD supported by
of interfaces configured for use by the advertising IGP instance. the node on the set of interfaces configured for use by the
MSD values may be learned via a hardware API or may be provisioned.. advertising IGP instance. MSD values may be learned via a hardware
API or may be provisioned..
0 1 2 3 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 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 | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MSD Type and Value ... | MSD-Type | MSD-Value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: Node MSD TLV Figure 1: Node MSD TLV
The Type: TBD1 The Type: TBD1
Length: variable (minimum of 2, multiple of 2 octets) and represents Length: variable (multiple of 2 octets) and represents the total
the total length of value field. length of value field in octets.
Value: consists of one or more pairs of a 1 octet MSD-type and 1 Value: consists of one or more pairs of a 1 octet MSD-type and 1
octet MSD-Value. octet MSD-Value.
MSD-Type: one of the values defined in the IGP MSD Types registry MSD-Type: one of the values defined in the IGP MSD Types registry
defined in [I-D.ietf-isis-segment-routing-msd]. defined in [I-D.ietf-isis-segment-routing-msd].
MSD-Value: a number in the range of 0-255. For all MSD-Types, 0 MSD-Value: a number in the range of 0-255. For all MSD-Types, 0
represents lack of the ability to impose MSD stack of any depth; any represents lack of the ability to impose MSD stack of any depth; any
other value represents that of the node. This value MUST represent other value represents that of the node. This value MUST represent
the lowest value supported by any link configured for use by the the lowest value supported by any link configured for use by the
advertising OSPF instance. advertising OSPF instance.
This TLV is applicable to OSPFv2 and to OSPFv3 [RFC5838] and is This TLV is applicable to OSPFv2 and to OSPFv3 and is optional. The
optional. The scope of the advertisement is specific to the scope of the advertisement is specific to the deployment.
deployment.
When multiple Node MSD TLVs are received from a given router, the When multiple Node MSD TLVs are received from a given router, the
receiver MUST use the first occurrence of the TLV in the Router receiver MUST use the first occurrence of the TLV in the Router
Information LSA. If the Node MSD TLV appears in multiple Router Information LSA. If the Node MSD TLV appears in multiple Router
Information LSAs that have different flooding scopes, the Node MSD Information LSAs that have different flooding scopes, the Node MSD
TLV in the Router Information LSA with the area-scoped flooding scope TLV in the Router Information LSA with the area-scoped flooding scope
MUST be used. If the Node MSD TLV appears in multiple Router MUST be used. If the Node MSD TLV appears in multiple Router
Information LSAs that have the same flooding scope, the Node MSD TLV Information LSAs that have the same flooding scope, the Node MSD TLV
in the Router Information (RI) LSA with the numerically smallest in the Router Information (RI) LSA with the numerically smallest
Instance ID MUST be used and subsequent instances of the Node MSD TLV Instance ID MUST be used and subsequent instances of the Node MSD TLV
skipping to change at page 5, line 31 skipping to change at page 5, line 31
The link sub-TLV is defined to carry the MSD of the interface The link sub-TLV is defined to carry the MSD of the interface
associated with the link. MSD values may be learned via a hardware associated with the link. MSD values may be learned via a hardware
API or may be provisioned. API or may be provisioned.
0 1 2 3 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 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 | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MSD Type and Value ... | | MSD-Type | MSD-Value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: Link MSD Sub-TLV Figure 2: Link MSD Sub-TLV
Type: Type:
For OSPFv2, the Link level MSD value is advertised as an optional For OSPFv2, the Link level MSD value is advertised as an optional
Sub-TLV of the OSPFv2 Extended Link TLV as defined in [RFC7684], and Sub-TLV of the OSPFv2 Extended Link TLV as defined in [RFC7684], and
has value of TBD2. has a type of TBD2.
For OSPFv3, the Link level MSD value is advertised as an optional For OSPFv3, the Link level MSD value is advertised as an optional
Sub-TLV of the E-Router-LSA TLV as defined in [RFC8362], and has Sub-TLV of the E-Router-LSA TLV as defined in [RFC8362], and has a
value of TBD3. type of TBD3.
Length: variable and similar to that, defined in Section 2. Length: variable and same as defined in Section 2.
Value: consists of one or more pairs of a 1 octet MSD-type and 1 Value: consists of one or more pairs of a 1 octet MSD-type and 1
octet MSD-Value. octet MSD-Value.
MSD-Type: one of the values defined in the MSD Types registry defined MSD-Type: one of the values defined in the MSD Types registry defined
in [I-D.ietf-isis-segment-routing-msd]. in [I-D.ietf-isis-segment-routing-msd].
MSD-Value field contains Link MSD of the router originating the MSD-Value field contains Link MSD of the router originating the
corresponding LSA as specified for OSPFv2 and OSPFv3. Link MSD is a corresponding LSA as specified for OSPFv2 and OSPFv3. Link MSD is a
number in the range of 0-255. For all MSD-Types, 0 represents lack number in the range of 0-255. For all MSD-Types, 0 represents lack
of the ability to impose MSD stack of any depth; any other value of the ability to impose MSD stack of any depth; any other value
represents that of the particular link when used as an outgoing represents that of the particular link when used as an outgoing
interface. interface.
Other MSD Types are reserved for future extensions. If this sub-TLV is advertised multiple times in the same OSPFv2
Extended Link Opaque LSA/E-Router-LSA, only the first instance of the
If this TLV is advertised multiple times in the same OSPFv2 Extended TLV MUST be used by receiving OSPF routers. This situation SHOULD be
Link Opaque LSA, only the first instance of the TLV is used by logged as an error.
receiving OSPFv2 routers. This situation SHOULD be logged as an
error.
If this TLV is advertised multiple times for the same link in If this sub-TLV is advertised multiple times for the same link in
different OSPFv2 Extended Link Opaque LSAs originated by the same different OSPF Extended Link Opaque LSAs/E-Router-LSAs originated by
OSPFv2 router, the OSPFv2 Extended Link TLV in the OSPFv2 Extended the same OSPF router, the OSPFv2 Extended Link TLV in the OSPFv2
Link Opaque LSA with the smallest Opaque ID is used by receiving Extended Link Opaque LSA with the smallest Opaque ID or in the OSPFv3
OSPFv2 routers. This situation may be logged as a warning. E-Router-LSA with the smallest Link State ID is used by receiving
OSPF routers. This situation MAY be logged as a warning.
4. Using Node and Link MSD Advertisements 4. Using Node and Link MSD Advertisements
When Link MSD is present for a given MSD type, the value of the Link When Link MSD is present for a given MSD type, the value of the Link
MSD MUST take preference over the Node MSD. When a Link MSD type is MSD MUST take preference over the Node MSD. When a Link MSD type is
not signalled but the Node MSD type is, then the value of that Link not signalled but the Node MSD type is, then the value of that Link
MSD type MUST be considered as the corresponding Node MSD type value. MSD type MUST be considered as the corresponding Node MSD type value.
In order to increase flooding efficiency, it is RECOMMENDED, that In order to increase flooding efficiency, it is RECOMMENDED, that
routers with homogenous link MSD values advertise just the Node MSD routers with homogenous link MSD values advertise just the Node MSD
value. value.
The meaning of the absence of both Node and Link MSD advertisements The meaning of the absence of both Node and Link MSD advertisements
for a given MSD type is specific to the MSD type. Generally it can for a given MSD type is specific to the MSD type. Generally it can
only be inferred that the advertising node does not support only be inferred that the advertising node does not support
advertisement of that MSD type. However, in some cases the lack of advertisement of that MSD type. However, in some cases the lack of
advertisement might imply that the functionality associated with the advertisement might imply that the functionality associated with the
MSD type is not supported. The correct interpretation MUST be MSD type is not supported. The correct interpretation MUST be
specified when an MSD type is defined. specified when an MSD type is defined.
5. Base MPLS Imposition MSD 5. IANA Considerations
The Base MPLS Imposition MSD (BMI-MSD) signals the total number of
MPLS labels a node is capable of imposing, including all
service/transport/special labels.
Absence of BMI-MSD advertisements indicates solely that the
advertising node does not support advertisement of this capability.
Assignment of MSD-Type for BMI-MSD is defined in
[I-D.ietf-isis-segment-routing-msd].
6. IANA Considerations
This document requests IANA to allocate TLV type (TBD1) from the OSPF This document requests IANA to allocate TLV type (TBD1) from the OSPF
Router Information (RI) TLVs Registry as defined by [RFC7770]. IANA Router Information (RI) TLVs Registry as defined by [RFC7770]. IANA
has allocated the value 12 through the early assignment process. has allocated the value 12 through the early assignment process.
Also, this document requests IANA to allocate a sub-TLV type (TBD2) Also, this document requests IANA to allocate a sub-TLV type (TBD2)
from the OSPFv2 Extended Link TLV Sub-TLVs registry. IANA has from the OSPFv2 Extended Link TLV Sub-TLVs registry. IANA has
allocated the the value 6 through the early assignment process. allocated the the value 6 through the early assignment process.
Finally, this document requests IANA to allocate a sub-TLV type Finally, this document requests IANA to allocate a sub-TLV type
(TBD3) from the OSPFv3 Extended-LSA Sub-TLV registry. (TBD3) from the OSPFv3 Extended-LSA Sub-TLV registry.
7. Security Considerations 6. Security Considerations
Security concerns for OSPF are addressed in [RFC7474]. Further Security concerns for OSPF are addressed in [RFC7474]. Further
security analysis for OSPF protocol is done in [RFC6863] including security analysis for OSPF protocol is done in [RFC6863] Security
analysis of both the above documents. Security considerations, as considerations, as specified by [RFC7770], [RFC7684] and [RFC8362]
specified by [RFC7770], [RFC7684] and [RFC8362] are applicable to are applicable to this document.
this document.
Advertisement of an incorrect MSD value may result: in a path Advertisement of an incorrect MSD value may result: in a path
computation failing and the service unavailable or instantiation of a computation failing and the service unavailable or instantiation of a
path that can't be supported by the head-end (the node performing the path that can't be supported by the head-end (the node performing the
imposition). imposition).
8. Contributors 7. Contributors
The following people contributed to this document: The following people contributed to this document:
Les Ginsberg Les Ginsberg
Email: ginsberg@cisco.com Email: ginsberg@cisco.com
9. Acknowledgements 8. Acknowledgements
The authors would like to thank Acee Lindem, Ketan Talaulikar, Tal The authors would like to thank Acee Lindem, Ketan Talaulikar, Tal
Mizrahi, Stephane Litkowski and Bruno Decraene for their reviews and Mizrahi, Stephane Litkowski and Bruno Decraene for their reviews and
valuable comments. valuable comments.
10. References 9. References
10.1. Normative References
9.1. Normative References
[I-D.ietf-isis-segment-routing-msd] [I-D.ietf-isis-segment-routing-msd]
Tantsura, J., Chunduri, U., Aldrin, S., and L. Ginsberg, Tantsura, J., Chunduri, U., Aldrin, S., and L. Ginsberg,
"Signaling MSD (Maximum SID Depth) using IS-IS", draft- "Signaling MSD (Maximum SID Depth) using IS-IS", draft-
ietf-isis-segment-routing-msd-12 (work in progress), May ietf-isis-segment-routing-msd-13 (work in progress), July
2018. 2018.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC7474] Bhatia, M., Hartman, S., Zhang, D., and A. Lindem, Ed.,
"Security Extension for OSPFv2 When Using Manual Key
Management", RFC 7474, DOI 10.17487/RFC7474, April 2015,
<https://www.rfc-editor.org/info/rfc7474>.
[RFC7684] Psenak, P., Gredler, H., Shakir, R., Henderickx, W., [RFC7684] Psenak, P., Gredler, H., Shakir, R., Henderickx, W.,
Tantsura, J., and A. Lindem, "OSPFv2 Prefix/Link Attribute Tantsura, J., and A. Lindem, "OSPFv2 Prefix/Link Attribute
Advertisement", RFC 7684, DOI 10.17487/RFC7684, November Advertisement", RFC 7684, DOI 10.17487/RFC7684, November
2015, <https://www.rfc-editor.org/info/rfc7684>. 2015, <https://www.rfc-editor.org/info/rfc7684>.
[RFC7770] Lindem, A., Ed., Shen, N., Vasseur, JP., Aggarwal, R., and [RFC7770] Lindem, A., Ed., Shen, N., Vasseur, JP., Aggarwal, R., and
S. Shaffer, "Extensions to OSPF for Advertising Optional S. Shaffer, "Extensions to OSPF for Advertising Optional
Router Capabilities", RFC 7770, DOI 10.17487/RFC7770, Router Capabilities", RFC 7770, DOI 10.17487/RFC7770,
February 2016, <https://www.rfc-editor.org/info/rfc7770>. February 2016, <https://www.rfc-editor.org/info/rfc7770>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>. May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8362] Lindem, A., Roy, A., Goethals, D., Reddy Vallem, V., and [RFC8362] Lindem, A., Roy, A., Goethals, D., Reddy Vallem, V., and
F. Baker, "OSPFv3 Link State Advertisement (LSA) F. Baker, "OSPFv3 Link State Advertisement (LSA)
Extensibility", RFC 8362, DOI 10.17487/RFC8362, April Extensibility", RFC 8362, DOI 10.17487/RFC8362, April
2018, <https://www.rfc-editor.org/info/rfc8362>. 2018, <https://www.rfc-editor.org/info/rfc8362>.
10.2. Informative References 9.2. Informative References
[I-D.ietf-idr-bgp-ls-segment-routing-msd] [I-D.ietf-idr-bgp-ls-segment-routing-msd]
Tantsura, J., Chunduri, U., Mirsky, G., and S. Sivabalan, Tantsura, J., Chunduri, U., Mirsky, G., and S. Sivabalan,
"Signaling Maximum SID Depth using Border Gateway Protocol "Signaling MSD (Maximum SID Depth) using Border Gateway
Link-State", draft-ietf-idr-bgp-ls-segment-routing-msd-01 Protocol Link-State", draft-ietf-idr-bgp-ls-segment-
(work in progress), October 2017. routing-msd-02 (work in progress), August 2018.
[I-D.ietf-ospf-mpls-elc] [I-D.ietf-ospf-mpls-elc]
Xu, X., Kini, S., Sivabalan, S., Filsfils, C., and S. Xu, X., Kini, S., Sivabalan, S., Filsfils, C., and S.
Litkowski, "Signaling Entropy Label Capability and Litkowski, "Signaling Entropy Label Capability and Entropy
Readable Label-stack Depth Using OSPF", draft-ietf-ospf- Readable Label-stack Depth Using OSPF", draft-ietf-ospf-
mpls-elc-05 (work in progress), January 2018. mpls-elc-06 (work in progress), August 2018.
[I-D.ietf-pce-segment-routing] [I-D.ietf-pce-segment-routing]
Sivabalan, S., Filsfils, C., Tantsura, J., Henderickx, W., Sivabalan, S., Filsfils, C., Tantsura, J., Henderickx, W.,
and J. Hardwick, "PCEP Extensions for Segment Routing", and J. Hardwick, "PCEP Extensions for Segment Routing",
draft-ietf-pce-segment-routing-12 (work in progress), June draft-ietf-pce-segment-routing-12 (work in progress), June
2018. 2018.
[RFC5838] Lindem, A., Ed., Mirtorabi, S., Roy, A., Barnes, M., and
R. Aggarwal, "Support of Address Families in OSPFv3",
RFC 5838, DOI 10.17487/RFC5838, April 2010,
<https://www.rfc-editor.org/info/rfc5838>.
[RFC6863] Hartman, S. and D. Zhang, "Analysis of OSPF Security [RFC6863] Hartman, S. and D. Zhang, "Analysis of OSPF Security
According to the Keying and Authentication for Routing According to the Keying and Authentication for Routing
Protocols (KARP) Design Guide", RFC 6863, Protocols (KARP) Design Guide", RFC 6863,
DOI 10.17487/RFC6863, March 2013, DOI 10.17487/RFC6863, March 2013,
<https://www.rfc-editor.org/info/rfc6863>. <https://www.rfc-editor.org/info/rfc6863>.
[RFC7474] Bhatia, M., Hartman, S., Zhang, D., and A. Lindem, Ed.,
"Security Extension for OSPFv2 When Using Manual Key
Management", RFC 7474, DOI 10.17487/RFC7474, April 2015,
<https://www.rfc-editor.org/info/rfc7474>.
[RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and [RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and
S. Ray, "North-Bound Distribution of Link-State and S. Ray, "North-Bound Distribution of Link-State and
Traffic Engineering (TE) Information Using BGP", RFC 7752, Traffic Engineering (TE) Information Using BGP", RFC 7752,
DOI 10.17487/RFC7752, March 2016, DOI 10.17487/RFC7752, March 2016,
<https://www.rfc-editor.org/info/rfc7752>. <https://www.rfc-editor.org/info/rfc7752>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>.
Authors' Addresses Authors' Addresses
Jeff Tantsura Jeff Tantsura
Nuage Networks Nuage Networks
Email: jefftant.ietf@gmail.com Email: jefftant.ietf@gmail.com
Uma Chunduri Uma Chunduri
Huawei Technologies Huawei Technologies
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