draft-ietf-ospf-segment-routing-msd-09.txt   rfc8476.txt 
OSPF Working Group J. Tantsura Internet Engineering Task Force (IETF) J. Tantsura
Internet-Draft Nuage Networks Request for Comments: 8476 Apstra, Inc.
Intended status: Standards Track U. Chunduri Category: Standards Track U. Chunduri
Expires: August 30, 2018 Huawei Technologies ISSN: 2070-1721 Huawei Technologies
S. Aldrin S. Aldrin
Google, Inc Google, Inc.
P. Psenak P. Psenak
Cisco Systems Cisco Systems
February 26, 2018 December 2018
Signaling MSD (Maximum SID Depth) using OSPF Signaling Maximum SID Depth (MSD) Using OSPF
draft-ietf-ospf-segment-routing-msd-09
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 is entities (e.g., centralized controllers) to determine whether a
supportable in a given network. This document only defines one type particular Segment Identifier (SID) stack can be supported in a given
of MSD (maximum label imposition) - but defines an encoding which can network. This document only refers to the Signaling MSD as defined
support other MSD types. Here the term OSPF means both OSPFv2 and in RFC 8491, but it defines an encoding that can support other MSD
OSPFv3. types. Here, the term "OSPF" means both OSPFv2 and OSPFv3.
Status of This Memo Status of This Memo
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provisions of BCP 78 and BCP 79.
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Internet Standards is available in Section 2 of RFC 7841.
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and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc8476.
Copyright Notice Copyright Notice
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction ....................................................3
1.1. Conventions used in this document . . . . . . . . . . . . 3 1.1. Terminology ................................................4
1.1.1. Terminology . . . . . . . . . . . . . . . . . . . . . 3 1.2. Requirements Language ......................................4
1.2. Requirements Language . . . . . . . . . . . . . . . . . . 3 2. Node MSD Advertisement ..........................................5
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Link MSD Sub-TLV ................................................6
3. Node MSD TLV . . . . . . . . . . . . . . . . . . . . . . . . 4 4. Procedures for Defining and Using Node and Link MSD
4. Link MSD sub-TLV . . . . . . . . . . . . . . . . . . . . . . 5 Advertisements ..................................................7
5. Using Node and Link MSD Advertisements . . . . . . . . . . . 5 5. IANA Considerations .............................................7
6. Base MPLS Imposition MSD . . . . . . . . . . . . . . . . . . 6 6. Security Considerations .........................................8
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 7. References ......................................................9
8. Security Considerations . . . . . . . . . . . . . . . . . . . 7 7.1. Normative References .......................................9
9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 7 7.2. Informative References ....................................10
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7 Acknowledgements ..................................................11
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 7 Contributors ......................................................11
11.1. Normative References . . . . . . . . . . . . . . . . . . 7 Authors' Addresses ................................................11
11.2. Informative References . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
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 learn the Maximum SID
Depth(MSD) which can be imposed at the node/link a given SR path is Depth (MSD) that can be imposed at each node/link on a given SR path.
applied so as to insure that the SID stack depth of a computed path This ensures that the Segment Identifier (SID) stack depth of a
doesn't exceed the number of SIDs the node is capable of imposing. computed path doesn't exceed the number of SIDs the node is capable
of imposing.
PCEP SR extensions draft [I-D.ietf-pce-segment-routing] signals MSD [PCEP-EXT] defines how to signal MSD in the Path Computation Element
in SR PCE Capability TLV and METRIC Object. However, if PCEP is not Communication Protocol (PCEP). However, if PCEP is not supported/
supported/configured on the head-end of a SR tunnel or a Binding-SID configured on the head-end of an SR tunnel or a Binding-SID anchor
anchor node and controller does not participate in IGP routing, it node, and the controller does not participate in IGP routing, it has
has no way to learn the MSD of nodes and links which has been no way of learning the MSD of nodes and links. BGP-LS (Distribution
configured. BGP-LS [RFC7752] defines a way to expose topology and of Link-State and TE Information Using BGP) [RFC7752] defines a way
associated attributes and capabilities of the nodes in that topology to expose topology and associated attributes and capabilities of the
to a centralized controller. MSD signaling by BGP-LS has been nodes in that topology to a centralized controller. MSD signaling by
defined in [I-D.ietf-idr-bgp-ls-segment-routing-msd]. Typically, BGP-LS has been defined in [MSD-BGP]. Typically, BGP-LS is
BGP-LS is configured on a small number of nodes, that do not configured on a small number of nodes that do not necessarily act as
necessarily act as head-ends. In order, for BGP-LS to signal MSD for head-ends. In order for BGP-LS to signal MSD for all the nodes and
all the nodes and links in the network MSD is relevant, MSD links in the network for which MSD is relevant, MSD capabilities
capabilites should be advertised to every OSPF router in the network. SHOULD be advertised by every OSPF router in the network.
Other types of MSD are known to be useful. For example, Other types of MSDs are known to be useful. For example, [ELC-ISIS]
[I-D.ietf-ospf-mpls-elc] defines Readable Label Depth Capability defines Entropy Readable Label Depth (ERLD), which is used by a
(RLDC) that is used by a head-end to insert Entropy Label (EL) at head-end to insert an Entropy Label (EL) at a depth where it can be
appropriate depth, so it could be read by transit nodes. 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 creates more types of MSDs at node and/or link granularity. In the future,
an IANA registry for assigning MSD type identifiers. It also defines it is expected that new MSD-Types will be defined to signal
one MSD type called Base MPLS Imposition MSD. In the future it is additional capabilities, e.g., ELs, SIDs that can be imposed through
expected that new MSD types will be defined to signal additional recirculation, or SIDs associated with another data plane such
capabilities e.g., entropy labels, SIDs that can be imposed through as IPv6.
recirculation, or SIDs associated with another dataplane e.g., IPv6.
1.1. Conventions used in this document MSD advertisements MAY be useful even if SR itself is not enabled.
For example, in a non-SR MPLS network, MSD defines the maximum label
depth.
1.1.1. Terminology 1.1. Terminology
BGP-LS: Distribution of Link-State and TE Information using Border This memo makes use of the terms defined in [RFC7770].
Gateway Protocol
BMI: Base MPLS Imposition is the number of MPLS labels which can be BGP-LS: Distribution of Link-State and TE Information Using BGP
imposed inclusive of any service/transport labels
OSPF: Open Shortest Path First OSPF: Open Shortest Path First
MSD: Maximum SID Depth - the number of SIDs a node or a link on a MSD: Maximum SID Depth - the number of SIDs supported by a node
node can support or a link on a node
PCC: Path Computation Client SID: Segment Identifier as defined in [RFC8402]
PCE: Path Computation Element Label Imposition: Imposition is the act of modifying and/or adding
labels to the outgoing label stack associated with a packet.
This includes:
PCEP: Path Computation Element Protocol * replacing the label at the top of the label stack with a
new label
SID: Segment Identifier * pushing one or more new labels onto the label stack
SR: Segment Routing The number of labels imposed is then the sum of the number of labels
that are replaced and the number of labels that are pushed. See
[RFC3031] for further details.
1.2. Requirements Language PCEP: Path Computation Element Communication Protocol
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", SR: Segment Routing
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
2. Terminology LSA: Link State Advertisement
This memo makes use of the terms defined in [RFC4970]. RI: Router Information
3. Node MSD TLV 1.2. Requirements Language
A new TLV within the body of the OSPF RI Opaque LSA, called Node MSD The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
TLV is defined to carry the provisioned SID depth of the router "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
originating the RI LSA. Node MSD is the lowest MSD supported by the "OPTIONAL" in this document are to be interpreted as described in
node. BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
0 1 2 3 2. Node MSD Advertisement
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The Node MSD TLV within the body of the OSPF RI Opaque LSA [RFC7770]
| Type | Length | is defined to carry the provisioned SID depth of the router
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ originating the RI LSA. Node MSD is the smallest MSD supported by
| Sub-Type and Value ... the node on the set of interfaces configured for use by the
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ... advertising IGP instance. MSD values may be learned via a hardware
API or may be provisioned.
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MSD-Type | MSD-Value | MSD-Type... | MSD-Value... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: Node MSD TLV Figure 1: Node MSD TLV
The Type (2 bytes) of this TLV has value of 12. Type: 12
Length is variable (minimum of 2, multiple of 2 octets) and Length: variable (multiple of 2 octets); represents the total length
represents the total length of value field. of the value field in octets.
Value field consists of a 1 octet sub-type (IANA Registry) and 1 Value: consists of one or more pairs of a 1-octet MSD-Type and
octet value. 1-octet MSD-Value.
Sub-Type 1 (IANA Section), MSD and the Value field contains maximum MSD-Type: one of the values defined in the "IGP MSD-Types" registry
MSD of the router originating the RI LSA. Node Maximum MSD is a defined in [RFC8491].
number in the range of 0-254. 0 represents lack of the ability to
impose MSD stack of any depth; any other value represents that of the
node. This value SHOULD represent the lowest value supported by
node.
Other Sub-types other than defined above are reserved for future MSD-Value: a number in the range of 0-255. For all MSD-Types, 0
extensions. represents the lack of ability to impose an MSD stack of any depth;
any other value represents that of the node. This value MUST
represent the lowest value supported by any link configured for use
by the advertising OSPF instance.
This TLV is applicable to OSPFv2 and to OSPFv3 [RFC5838] and is This TLV is optional and is applicable to both OSPFv2 and OSPFv3.
optional. The scope of the advertisement is specific to the The scope of the advertisement is specific to the deployment.
deployment.
4. Link MSD sub-TLV When multiple Node MSD TLVs are received from a given router, the
receiver MUST use the first occurrence of the TLV in the Router
Information (RI) LSA. If the Node MSD TLV appears in multiple RI
LSAs that have different flooding scopes, the Node MSD TLV in the RI
LSA with the area-scoped flooding scope MUST be used. If the Node
MSD TLV appears in multiple RI LSAs that have the same flooding
scope, the Node MSD TLV in the RI LSA with the numerically smallest
Instance ID MUST be used and other instances of the Node MSD TLV MUST
be ignored. The RI LSA can be advertised at any of the defined
opaque flooding scopes (link, area, or Autonomous System (AS)). For
the purpose of Node MSD TLV advertisement, area-scoped flooding is
RECOMMENDED.
A new sub-TLV called Link MSD sub-TLV is defined to carry the 3. Link MSD Sub-TLV
provisioned SID depth of the interface associated with the link.
0 1 2 3 The Link MSD sub-TLV is defined to carry the MSD of the interface
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 associated with the link. MSD values may be learned via a hardware
API or may be provisioned.
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 0 1 2 3
| Type | Length | 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sub-Type and Value ... | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MSD-Type | MSD-Value | MSD-Type... | MSD-Value... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: Link MSD Sub-TLV Figure 2: Link MSD Sub-TLV
The Type (2 bytes) of this TLV: Type:
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 has a type of 6.
For OSPFv2, 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 OSPFv2 Extended Link TLV as defined in [RFC7684], and has sub-TLV of the E-Router-LSA TLV as defined in [RFC8362] and has a
value of 6. type of 9.
For OSPFv3, the Link level MSD value is advertised as an optional Length: variable; same as defined in Section 2.
Sub-TLV of the Router-Link TLV as defined in
[I-D.ietf-ospf-ospfv3-lsa-extend], and has value of 16 (Suggested
value - to be assigned by IANA).
Length is variable and similar to what is defined in Section 3. Value: consists of one or more pairs of a 1-octet MSD-Type and
1-octet MSD-Value.
Value field consists of a 1 octet sub-type (IANA Registry) and 1 MSD-Type: one of the values defined in the "IGP MSD-Types" registry
octet value. defined in [RFC8491].
Sub-Type 1 (IANA Section), MSD and the Value field contains Link MSD The MSD-Value field contains the Link MSD of the router originating
of the router originating the corresponding LSA as specified for the corresponding LSA as specified for OSPFv2 and OSPFv3. The Link
OSPFv2 and OSPFv3. Link MSD is a number in the range of 0-254. 0 MSD is 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 the lack of ability to impose an MSD stack of any depth;
other value represents that of the particular link MSD value. any other value represents that of the particular link when used as
an outgoing interface.
Other Sub-types other than defined above are reserved for future If this sub-TLV is advertised multiple times for the same link in
extensions. different OSPF Extended Link Opaque LSAs / E-Router-LSAs originated
by the same OSPF router, the sub-TLV in the OSPFv2 Extended Link
Opaque LSA with the smallest Opaque ID or in the OSPFv3 E-Router-LSA
with the smallest Link State ID MUST be used by receiving OSPF
routers. This situation SHOULD be logged as an error.
5. Using Node and Link MSD Advertisements 4. Procedures for Defining and 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 be used in preference to the Node MSD. MSD MUST take precedence over the Node MSD. When a Link MSD-Type is
not signaled but the Node MSD-Type is, then the Node MSD-Type value
MUST be considered as the MSD value for that link.
In order to increase flooding efficiency, it is RECOMMENDED that
routers with homogenous Link MSD values advertise just the Node MSD
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. Per [RFC8491], the correct interpretation
specified when an MSD type is defined. MUST be specified when an MSD-Type is defined.
6. Base MPLS Imposition MSD 5. IANA Considerations
Base MPLS Imposition MSD (BMI-MSD) signals the total number of MPLS This specification updates several existing OSPF registries.
labels a node is capable of imposing, including any service/transport
labels.
Absence of BMI-MSD advertisements indicates only that the advertising IANA has allocated TLV type 12 from the "OSPF Router Information (RI)
node does not support advertisement of this capability. TLVs" registry as defined by [RFC7770].
7. IANA Considerations Value Description Reference
----- --------------- -------------
12 Node MSD This document
This document includes a request to IANA to allocate TLV type codes Figure 3: RI Node MSD
for the new TLV proposed in Section 3 of this document from OSPF
Router Information (RI) TLVs Registry as defined by [RFC4970]. For
the link MSD, we request IANA to allocate new sub-TLV codes as
proposed in Section 4 from OSPFv2 Extended Link TLV Sub-TLVs registry
and from Router-Link TLV defined in OSPFv3 Extend-LSA Sub-TLV
registry.
This document requests creation of a new IANA managed registry under IANA has allocated sub-TLV type 6 from the "OSPFv2 Extended Link TLV
a new category of "Interior Gateway Protocol (IGP) Parameters" IANA Sub-TLVs" registry.
registries to identify MSD types as proposed in Section 3, Section 4.
The registration procedure is "Expert Review" as defined in
[RFC8126]. Suggested registry name is "MSD types". Types are an
unsigned 8 bit number. The following values are defined by this
document
Value Name Reference Value Description Reference
----- --------------------- ------------- ----- --------------- -------------
0 Reserved This document 6 OSPFv2 Link MSD This document
1 Base MPLS Imposition MSD This document
2-250 Unassigned This document
251-254 Experimental This document
255 Reserved This document
Figure 3: MSD Types Codepoints Registry Figure 4: OSPFv2 Link MSD
8. Security Considerations IANA has allocated sub-TLV type 9 from the "OSPFv3 Extended-LSA
Sub-TLVs" registry.
Security considerations, as specified by [RFC7770] are applicable to Value Description Reference
this document ----- --------------- -------------
9 OSPFv3 Link MSD This document
9. Contributors Figure 5: OSPFv3 Link MSD
The following people contributed to this document: 6. Security Considerations
Les Ginsberg Security concerns for OSPF are addressed in [RFC7474], [RFC4552], and
[RFC7166]. Further security analysis for the OSPF protocol is done
in [RFC6863]. Security considerations as specified by [RFC7770],
[RFC7684], and [RFC8362] are applicable to this document.
Email: ginsberg@cisco.com Implementations MUST ensure that malformed TLVs and sub-TLVs defined
in this document are detected and do not provide a vulnerability for
attackers to crash the OSPF router or routing process. Reception of
malformed TLVs or sub-TLVs SHOULD be counted and/or logged for
further analysis. Logging of malformed TLVs and sub-TLVs SHOULD be
rate-limited to prevent a Denial-of-Service (DoS) attack (distributed
or otherwise) from overloading the OSPF control plane.
10. Acknowledgements Advertisement of an incorrect MSD value may have negative
consequences. If the value is smaller than supported, path
computation may fail to compute a viable path. If the value is
larger than supported, an attempt to instantiate a path that can't be
supported by the head-end (the node performing the SID imposition)
may occur.
The authors would like to thank Stephane Litkowski and Bruno Decraene The presence of this information may also inform an attacker of how
for their reviews and valuable comments. to induce any of the aforementioned conditions.
11. References There's no DoS risk specific to this extension, and it is not
vulnerable to replay attacks.
11.1. Normative References 7. References
7.1. Normative References
[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>.
[RFC4970] Lindem, A., Ed., Shen, N., Vasseur, JP., Aggarwal, R., and [RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol
S. Shaffer, "Extensions to OSPF for Advertising Optional Label Switching Architecture", RFC 3031,
Router Capabilities", RFC 4970, DOI 10.17487/RFC4970, July DOI 10.17487/RFC3031, January 2001,
2007, <https://www.rfc-editor.org/info/rfc4970>. <https://www.rfc-editor.org/info/rfc3031>.
[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 [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>.
11.2. Informative References [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in
RFC 2119 Key Words", BCP 14, RFC 8174,
DOI 10.17487/RFC8174, May 2017,
<https://www.rfc-editor.org/info/rfc8174>.
[I-D.ietf-idr-bgp-ls-segment-routing-msd] [RFC8362] Lindem, A., Roy, A., Goethals, D., Reddy Vallem, V., and
Tantsura, J., Chunduri, U., Mirsky, G., and S. Sivabalan, F. Baker, "OSPFv3 Link State Advertisement (LSA)
"Signaling Maximum SID Depth using Border Gateway Protocol Extensibility", RFC 8362, DOI 10.17487/RFC8362,
Link-State", draft-ietf-idr-bgp-ls-segment-routing-msd-01 April 2018, <https://www.rfc-editor.org/info/rfc8362>.
(work in progress), October 2017.
[I-D.ietf-ospf-mpls-elc] [RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L.,
Xu, X., Kini, S., Sivabalan, S., Filsfils, C., and S. Decraene, B., Litkowski, S., and R. Shakir, "Segment
Litkowski, "Signaling Entropy Label Capability and Routing Architecture", RFC 8402, DOI 10.17487/RFC8402,
Readable Label-stack Depth Using OSPF", draft-ietf-ospf- July 2018, <https://www.rfc-editor.org/info/rfc8402>.
mpls-elc-05 (work in progress), January 2018.
[I-D.ietf-ospf-ospfv3-lsa-extend] [RFC8491] Tantsura, J., Chunduri, U., Aldrin, S., and L. Ginsberg,
Lindem, A., Roy, A., Goethals, D., Vallem, V., and F. "Signaling Maximum SID Depth (MSD) Using IS-IS", RFC 8491,
Baker, "OSPFv3 LSA Extendibility", draft-ietf-ospf-ospfv3- DOI 10.17487/RFC8491, November 2018,
lsa-extend-23 (work in progress), January 2018. <https://www.rfc-editor.org/info/rfc8491>.
[I-D.ietf-pce-segment-routing] 7.2. Informative References
Sivabalan, S., Filsfils, C., Tantsura, J., Henderickx, W.,
[ELC-ISIS] Xu, X., Kini, S., Sivabalan, S., Filsfils, C., and S.
Litkowski, "Signaling Entropy Label Capability and Entropy
Readable Label-stack Depth Using OSPF", Work in Progress,
draft-ietf-ospf-mpls-elc-07, September 2018.
[MSD-BGP] Tantsura, J., Chunduri, U., Mirsky, G., and S. Sivabalan,
"Signaling MSD (Maximum SID Depth) using Border Gateway
Protocol Link-State", Work in Progress, draft-ietf-idr-
bgp-ls-segment-routing-msd-02, August 2018.
[PCEP-EXT] 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-11 (work in progress), Work in Progress, draft-ietf-pce-segment-routing-14,
November 2017. October 2018.
[RFC5838] Lindem, A., Ed., Mirtorabi, S., Roy, A., Barnes, M., and [RFC4552] Gupta, M. and N. Melam, "Authentication/Confidentiality
R. Aggarwal, "Support of Address Families in OSPFv3", for OSPFv3", RFC 4552, DOI 10.17487/RFC4552, June 2006,
RFC 5838, DOI 10.17487/RFC5838, April 2010, <https://www.rfc-editor.org/info/rfc4552>.
<https://www.rfc-editor.org/info/rfc5838>.
[RFC7684] Psenak, P., Gredler, H., Shakir, R., Henderickx, W., [RFC6863] Hartman, S. and D. Zhang, "Analysis of OSPF Security
Tantsura, J., and A. Lindem, "OSPFv2 Prefix/Link Attribute According to the Keying and Authentication for Routing
Advertisement", RFC 7684, DOI 10.17487/RFC7684, November Protocols (KARP) Design Guide", RFC 6863,
2015, <https://www.rfc-editor.org/info/rfc7684>. DOI 10.17487/RFC6863, March 2013,
<https://www.rfc-editor.org/info/rfc6863>.
[RFC7166] Bhatia, M., Manral, V., and A. Lindem, "Supporting
Authentication Trailer for OSPFv3", RFC 7166,
DOI 10.17487/RFC7166, March 2014,
<https://www.rfc-editor.org/info/rfc7166>.
[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 Acknowledgements
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017, The authors would like to thank Acee Lindem, Ketan Talaulikar, Tal
<https://www.rfc-editor.org/info/rfc8126>. Mizrahi, Stephane Litkowski, and Bruno Decraene for their reviews and
valuable comments.
Contributors
The following person contributed to this document:
Les Ginsberg
Email: ginsberg@cisco.com
Authors' Addresses Authors' Addresses
Jeff Tantsura Jeff Tantsura
Nuage Networks Apstra, Inc.
Email: jefftant.ietf@gmail.com Email: jefftant.ietf@gmail.com
Uma Chunduri Uma Chunduri
Huawei Technologies Huawei Technologies
Email: uma.chunduri@huawei.com Email: uma.chunduri@huawei.com
Sam Aldrin Sam Aldrin
Google, Inc Google, Inc.
Email: aldrin.ietf@gmail.com Email: aldrin.ietf@gmail.com
Peter Psenak Peter Psenak
Cisco Systems Cisco Systems
Email: ppsenak@cisco.com Email: ppsenak@cisco.com
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