draft-ietf-lsr-isis-srv6-extensions-00.txt   draft-ietf-lsr-isis-srv6-extensions-01.txt 
Networking Working Group P. Psenak, Ed. Networking Working Group P. Psenak, Ed.
Internet-Draft C. Filsfils Internet-Draft C. Filsfils
Intended status: Standards Track Cisco Systems Intended status: Standards Track Cisco Systems
Expires: December 2, 2019 A. Bashandy Expires: January 5, 2020 A. Bashandy
Arrcus Arrcus
B. Decraene B. Decraene
Orange Orange
Z. Hu Z. Hu
Huawei Technologies Huawei Technologies
May 31, 2019 July 4, 2019
IS-IS Extensions to Support Routing over IPv6 Dataplane IS-IS Extension to Support Segment Routing over IPv6 Dataplane
draft-ietf-lsr-isis-srv6-extensions-00.txt draft-ietf-lsr-isis-srv6-extensions-01.txt
Abstract Abstract
Segment Routing (SR) allows for a flexible definition of end-to-end Segment Routing (SR) allows for a flexible definition of end-to-end
paths by encoding paths as sequences of topological sub-paths, called paths by encoding paths as sequences of topological sub-paths, called
"segments". Segment routing architecture can be implemented over an "segments". Segment routing architecture can be implemented over an
MPLS data plane as well as an IPv6 data plane. This draft describes MPLS data plane as well as an IPv6 data plane. This draft describes
the IS-IS extensions required to support Segment Routing over an IPv6 the IS-IS extensions required to support Segment Routing over an IPv6
data plane. data plane.
skipping to change at page 1, line 49 skipping to change at page 1, line 49
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This Internet-Draft will expire on December 2, 2019. This Internet-Draft will expire on January 5, 2020.
Copyright Notice Copyright Notice
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. SRv6 Capabilities sub-TLV . . . . . . . . . . . . . . . . . . 3 2. SRv6 Capabilities sub-TLV . . . . . . . . . . . . . . . . . . 4
3. Advertising Supported Algorithms . . . . . . . . . . . . . . 4 3. Advertising Supported Algorithms . . . . . . . . . . . . . . 4
4. Advertising Maximum SRv6 SID Depths . . . . . . . . . . . . . 4 4. Advertising Maximum SRv6 SID Depths . . . . . . . . . . . . . 4
4.1. Maximum Segments Left MSD Type . . . . . . . . . . . . . 5 4.1. Maximum Segments Left MSD Type . . . . . . . . . . . . . 5
4.2. Maximum End Pop MSD Type . . . . . . . . . . . . . . . . 5 4.2. Maximum End Pop MSD Type . . . . . . . . . . . . . . . . 5
4.3. Maximum T.Insert MSD Type . . . . . . . . . . . . . . . . 5 4.3. Maximum T.Insert MSD Type . . . . . . . . . . . . . . . . 5
4.4. Maximum T.Encaps MSD Type . . . . . . . . . . . . . . . . 5 4.4. Maximum T.Encaps MSD Type . . . . . . . . . . . . . . . . 5
4.5. Maximum End D MSD Type . . . . . . . . . . . . . . . . . 6 4.5. Maximum End D MSD Type . . . . . . . . . . . . . . . . . 6
5. SRv6 SIDs and Reachability . . . . . . . . . . . . . . . . . 6 5. SRv6 SIDs and Reachability . . . . . . . . . . . . . . . . . 6
6. Advertising Locators and End SIDs . . . . . . . . . . . . . . 7 6. Advertising Locators and End SIDs . . . . . . . . . . . . . . 8
6.1. SRv6 Locator TLV Format . . . . . . . . . . . . . . . . . 8 6.1. SRv6 Locator TLV Format . . . . . . . . . . . . . . . . . 8
6.2. SRv6 End SID sub-TLV . . . . . . . . . . . . . . . . . . 9 6.2. SRv6 End SID sub-TLV . . . . . . . . . . . . . . . . . . 9
7. Advertising SRv6 End.X SIDs . . . . . . . . . . . . . . . . . 11 7. Advertising SRv6 Adjacency SIDs . . . . . . . . . . . . . . . 11
7.1. SRv6 End.X SID sub-TLV . . . . . . . . . . . . . . . . . 11 7.1. SRv6 End.X SID sub-TLV . . . . . . . . . . . . . . . . . 11
7.2. SRv6 LAN End.X SID sub-TLV . . . . . . . . . . . . . . . 13 7.2. SRv6 LAN End.X SID sub-TLV . . . . . . . . . . . . . . . 13
8. Advertising Endpoint Behaviors . . . . . . . . . . . . . . . 14 8. SRv6 SID Structure Sub-Sub-TLV . . . . . . . . . . . . . . . 14
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15 9. Advertising Endpoint Behaviors . . . . . . . . . . . . . . . 15
9.1. SRv6 Locator TLV . . . . . . . . . . . . . . . . . . . . 15 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16
9.1.1. SRv6 End SID sub-TLV . . . . . . . . . . . . . . . . 15 10.1. SRv6 Locator TLV . . . . . . . . . . . . . . . . . . . . 16
9.1.2. Revised sub-TLV table . . . . . . . . . . . . . . . . 16 10.1.1. SRv6 End SID sub-TLV . . . . . . . . . . . . . . . . 16
9.2. SRv6 Capabilities sub-TLV . . . . . . . . . . . . . . . . 16 10.1.2. Revised sub-TLV table . . . . . . . . . . . . . . . 17
9.3. SRv6 End.X SID and SRv6 LAN End.X SID sub-TLVs . . . . . 17 10.2. SRv6 Capabilities sub-TLV . . . . . . . . . . . . . . . 17
9.4. MSD Types . . . . . . . . . . . . . . . . . . . . . . . . 17 10.3. SRv6 End.X SID and SRv6 LAN End.X SID sub-TLVs . . . . . 18
10. Security Considerations . . . . . . . . . . . . . . . . . . . 17 10.4. MSD Types . . . . . . . . . . . . . . . . . . . . . . . 18
11. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 17 10.5. Sub-Sub-TLVs for SID Sub-TLVs . . . . . . . . . . . . . 18
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 18 11. Security Considerations . . . . . . . . . . . . . . . . . . . 19
12.1. Normative References . . . . . . . . . . . . . . . . . . 18 12. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 19
12.2. Informative References . . . . . . . . . . . . . . . . . 20 13. References . . . . . . . . . . . . . . . . . . . . . . . . . 20
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 21 13.1. Normative References . . . . . . . . . . . . . . . . . . 20
13.2. Informative References . . . . . . . . . . . . . . . . . 22
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 22
1. Introduction 1. Introduction
With Segment Routing (SR) [I-D.ietf-spring-segment-routing], a node With Segment Routing (SR) [I-D.ietf-spring-segment-routing], a node
steers a packet through an ordered list of instructions, called steers a packet through an ordered list of instructions, called
segments. segments.
Segments are identified through Segment Identifiers (SIDs). Segments are identified through Segment Identifiers (SIDs).
Segment Routing can be directly instantiated on the IPv6 data plane Segment Routing can be directly instantiated on the IPv6 data plane
through the use of the Segment Routing Header defined in through the use of the Segment Routing Header defined in
[I-D.ietf-6man-segment-routing-header]. SRv6 refers to this SR [I-D.ietf-6man-segment-routing-header]. SRv6 refers to this SR
instantiation on the IPv6 dataplane. instantiation on the IPv6 dataplane.
The network programming paradigm The network programming paradigm
[I-D.filsfils-spring-srv6-network-programming] is central to SRv6. [I-D.ietf-spring-srv6-network-programming] is central to SRv6. It
It describes how any function can be bound to a SID and how any describes how any function can be bound to a SID and how any network
network program can be expressed as a combination of SID's. program can be expressed as a combination of SID's.
This document specifies IS-IS extensions that allow the IS-IS This document specifies IS-IS extensions that allow the IS-IS
protocol to encode some of these functions. protocol to encode some of these functions.
Familiarity with the network programming paradigm Familiarity with the network programming paradigm
[I-D.filsfils-spring-srv6-network-programming] is necessary to [I-D.ietf-spring-srv6-network-programming] is necessary to understand
understand the extensions specified in this document. the extensions specified in this document.
This document defines one new top level IS-IS TLV and several new IS- This document defines one new top level IS-IS TLV and several new IS-
IS sub-TLVs. IS sub-TLVs.
The SRv6 Capabilities sub-TLV announces the ability to support SRv6 The SRv6 Capabilities sub-TLV announces the ability to support SRv6.
and some Endpoint functions listed in Section 7 as well as
advertising limitations when applying such Endpoint functions.
The SRv6 Locator top level TLV announces SRv6 locators - a form of Several new sub-TLVs are defined to advertise various SRv6 Maximum
summary address for the set of topology/algorithm specific SIDs SID Depths.
The new SRv6 Locator top level TLV announces SRv6 locators - a form
of summary address for the set of topology/algorithm specific SIDs
associated with a node. associated with a node.
The SRv6 End SID sub-TLV, the SRv6 End.X SID sub-TLV, and the SRv6 The SRv6 End SID sub-TLV, the SRv6 End.X SID sub-TLV, and the SRv6
LAN End.X SID sub-TLV are used to advertise which SIDs are LAN End.X SID sub-TLV are used to advertise which SIDs are
instantiated at a node and what Endpoint function is bound to each instantiated at a node and what Endpoint function is bound to each
instantiated SID. instantiated SID.
2. SRv6 Capabilities sub-TLV 2. SRv6 Capabilities sub-TLV
A node indicates that it has support for SRv6 by advertising a new A node indicates that it has support for SRv6 by advertising a new
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[I-D.ali-spring-srv6-oam]. [I-D.ali-spring-srv6-oam].
3. Advertising Supported Algorithms 3. Advertising Supported Algorithms
SRv6 capable router indicates supported algorithm(s) by advertising SRv6 capable router indicates supported algorithm(s) by advertising
the SR Algorithm TLV as defined in the SR Algorithm TLV as defined in
[I-D.ietf-isis-segment-routing-extensions]. [I-D.ietf-isis-segment-routing-extensions].
4. Advertising Maximum SRv6 SID Depths 4. Advertising Maximum SRv6 SID Depths
[I-D.ietf-isis-segment-routing-msd] defines the means to advertise [RFC8491] defines the means to advertise node/link specific values
node/link specific values for Maximum SID Depths (MSD) of various for Maximum SID Depths (MSD) of various types. Node MSDs are
types. Node MSDs are advertised in a sub-TLV of the Router advertised in a sub-TLV of the Router Capabilities TLV [RFC7981].
Capabilities TLV [RFC7981]. Link MSDs are advertised in a sub-TLV of
TLVs 22, 23, 141, 222, and 223. Link MSDs are advertised in a sub-TLV of TLVs 22, 23, 141, 222, and
223.
This document defines the relevant SRv6 MSDs and requests MSD type This document defines the relevant SRv6 MSDs and requests MSD type
assignments in the MSD Types registry created by assignments in the MSD Types registry created by [RFC8491].
[I-D.ietf-isis-segment-routing-msd].
4.1. Maximum Segments Left MSD Type 4.1. Maximum Segments Left MSD Type
The Maximum Segments Left MSD Type specifies the maximum value of the The Maximum Segments Left MSD Type specifies the maximum value of the
"SL" field [I-D.ietf-6man-segment-routing-header] in the SRH of a "SL" field [I-D.ietf-6man-segment-routing-header] in the SRH of a
received packet before applying the Endpoint function associated with received packet before applying the Endpoint function associated with
a SID. a SID.
SRH Max SL Type: 41 (Suggested value - to be assigned by IANA) SRH Max SL Type: 41 (Suggested value - to be assigned by IANA)
If no value is advertised the supported value is assumed to be 0. If no value is advertised the supported value is assumed to be 0.
4.2. Maximum End Pop MSD Type 4.2. Maximum End Pop MSD Type
The Maximum End Pop MSD Type specifies the maximum number of SIDs in The Maximum End Pop MSD Type specifies the maximum number of SIDs in
the top SRH in an SRH stack to which the router can apply "PSP" or the top SRH in an SRH stack to which the router can apply "PSP" or
USP" as defined in [I-D.filsfils-spring-srv6-network-programming] USP" as defined in [I-D.ietf-spring-srv6-network-programming]
flavors. flavors.
SRH Max End Pop Type: 42 (Suggested value - to be assigned by IANA) SRH Max End Pop Type: 42 (Suggested value - to be assigned by IANA)
If the advertised value is zero or no value is advertised If the advertised value is zero or no value is advertised
then it is assumed that the router cannot apply PSP or USP flavors. then it is assumed that the router cannot apply PSP or USP flavors.
4.3. Maximum T.Insert MSD Type 4.3. Maximum T.Insert MSD Type
The Maximum T.Insert MSD Type specifies the maximum number of SIDs The Maximum T.Insert MSD Type specifies the maximum number of SIDs
that can be inserted as part of the "T.insert" behavior as defined in that can be inserted as part of the "T.insert" behavior as defined in
[I-D.filsfils-spring-srv6-network-programming]. [I-D.ietf-spring-srv6-network-programming].
SRH Max T.insert Type: 43 (Suggested value - to be assigned by IANA) SRH Max T.insert Type: 43 (Suggested value - to be assigned by IANA)
If the advertised value is zero or no value is advertised If the advertised value is zero or no value is advertised
then the router is assumed not to support any variation then the router is assumed not to support any variation
of the "T.insert" behavior. of the "T.insert" behavior.
4.4. Maximum T.Encaps MSD Type 4.4. Maximum T.Encaps MSD Type
The Maximum T.Encaps MSD Type specifies the maximum number of SIDs The Maximum T.Encaps MSD Type specifies the maximum number of SIDs
that can be included as part of the "T.Encaps" behavior as defined in that can be included as part of the "T.Encaps" behavior as defined in
[I-D.filsfils-spring-srv6-network-programming] . [I-D.ietf-spring-srv6-network-programming] .
SRH Max T.encaps Type: 44 (Suggested value - to be assigned by IANA) SRH Max T.encaps Type: 44 (Suggested value - to be assigned by IANA)
If the advertised value is zero then the router can apply T.Encaps If the advertised value is zero then the router can apply T.Encaps
only by encapsulating the incoming packet in another only by encapsulating the incoming packet in another
IPv6 header without SRH the same way IPinIP encapsulation is IPv6 header without SRH the same way IPinIP encapsulation is
performed. performed.
If the advertised value is non-zero then the router supports both If the advertised value is non-zero then the router supports both
IPinIP and SRH encapsulation subject to the SID limitation IPinIP and SRH encapsulation subject to the SID limitation
specified by the advertised value. specified by the advertised value.
4.5. Maximum End D MSD Type 4.5. Maximum End D MSD Type
The Maximum End D MSD Type specifies the maximum number of SIDs in an The Maximum End D MSD Type specifies the maximum number of SIDs in an
SRH when performing decapsulation associated with "End.Dx" functions SRH when performing decapsulation associated with "End.Dx" functions
(e.g., "End.DX6" and "End.DT6") as defined in (e.g., "End.DX6" and "End.DT6") as defined in
[I-D.filsfils-spring-srv6-network-programming]. [I-D.ietf-spring-srv6-network-programming].
SRH Max End D Type: 45 (Suggested value - to be assigned by IANA) SRH Max End D Type: 45 (Suggested value - to be assigned by IANA)
If the advertised value is zero or no value is advertised If the advertised value is zero or no value is advertised
then it is assumed that the router cannot apply then it is assumed that the router cannot apply
"End.DX6" or "End.DT6" functions if the extension "End.DX6" or "End.DT6" functions if the extension
header right underneath the outer IPv6 header is an SRH. header right underneath the outer IPv6 header is an SRH.
5. SRv6 SIDs and Reachability 5. SRv6 SIDs and Reachability
As discussed in [I-D.filsfils-spring-srv6-network-programming], an As discussed in [I-D.ietf-spring-srv6-network-programming], an SRv6
SRv6 Segment Identifier (SID) is 128 bits and represented as Segment Identifier (SID) is 128 bits and represented as
LOC:FUNCT LOC:FUNCT
where LOC (the locator portion) is the L most significant bits and where LOC (the locator portion) is the L most significant bits and
FUNCT is the 128-L least significant bits. L is called the locator FUNCT is the 128-L least significant bits. L is called the locator
length and is flexible. Each operator is free to use the locator length and is flexible. Each operator is free to use the locator
length it chooses. length it chooses.
A node is provisioned with topology/algorithm specific locators for A node is provisioned with topology/algorithm specific locators for
each of the topology/algorithm pairs supported by that node. Each each of the topology/algorithm pairs supported by that node. Each
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Locators MUST be advertised in the SRv6 Locator TLV (see Locators MUST be advertised in the SRv6 Locator TLV (see
Section 6.1). Forwarding entries for the locators advertised in the Section 6.1). Forwarding entries for the locators advertised in the
SRv6 Locator TLV MUST be installed in the forwarding plane of SRv6 Locator TLV MUST be installed in the forwarding plane of
receiving SRv6 capable routers when the associated topology/algorithm receiving SRv6 capable routers when the associated topology/algorithm
is supported by the receiving node. is supported by the receiving node.
Locators are routable and MAY also be advertised in Prefix Locators are routable and MAY also be advertised in Prefix
Reachability TLVs (236 or 237). Reachability TLVs (236 or 237).
Locators associated with Flexible Algorithms SHOULD NOT be advertised
in Prefix Reachability TLVs (236 or 237).
Locators associated with algorithm 0 (for all supported topologies) Locators associated with algorithm 0 (for all supported topologies)
SHOULD be advertised in a Prefix Reachability TLV (236 or 237) so SHOULD be advertised in a Prefix Reachability TLV (236 or 237) so
that legacy routers (i.e., routers which do NOT support SRv6) will that legacy routers (i.e., routers which do NOT support SRv6) will
install a forwarding entry for algorithm 0 SRv6 traffic. install a forwarding entry for algorithm 0 SRv6 traffic.
In cases where a locator advertisement is received in both in a In cases where a locator advertisement is received in both in a
Prefix Reachability TLV and an SRv6 Locator TLV, the Prefix Prefix Reachability TLV and an SRv6 Locator TLV, the Prefix
Reachability advertisement MUST be preferred when installing entries Reachability advertisement MUST be preferred when installing entries
in the forwarding plane. This is to prevent inconsistent forwarding in the forwarding plane. This is to prevent inconsistent forwarding
entries on SRv6 capable/SRv6 incapable routers. entries on SRv6 capable/SRv6 incapable routers.
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Sub-TLV-length: 1 octet. Number of octets used by sub-TLVs Sub-TLV-length: 1 octet. Number of octets used by sub-TLVs
Optional sub-TLVs. Optional sub-TLVs.
6.2. SRv6 End SID sub-TLV 6.2. SRv6 End SID sub-TLV
The SRv6 End SID sub-TLV is introduced to advertise SRv6 Segment The SRv6 End SID sub-TLV is introduced to advertise SRv6 Segment
Identifiers (SID) with Endpoint functions which do not require a Identifiers (SID) with Endpoint functions which do not require a
particular neighbor in order to be correctly applied particular neighbor in order to be correctly applied
[I-D.filsfils-spring-srv6-network-programming]. SRv6 SIDs associated [I-D.ietf-spring-srv6-network-programming]. SRv6 SIDs associated
with a neighbor are advertised using the sub-TLVs defined in with a neighbor are advertised using the sub-TLVs defined in
Section 6. Section 6.
This new sub-TLV is advertised in the SRv6 Locator TLV defined in the This new sub-TLV is advertised in the SRv6 Locator TLV defined in the
previous section. SRv6 End SIDs inherit the topology/algorithm from previous section. SRv6 End SIDs inherit the topology/algorithm from
the parent locator. the parent locator.
The SRv6 End SID sub-TLV has the following format: The SRv6 End SID sub-TLV has the following format:
0 1 2 3 0 1 2 3
skipping to change at page 10, line 30 skipping to change at page 10, line 30
|Sub-sub-tlv-len| sub-sub-TLVs (variable) . . . | |Sub-sub-tlv-len| sub-sub-TLVs (variable) . . . |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 5 (Suggested value to be assigned by IANA) Type: 5 (Suggested value to be assigned by IANA)
Length: variable. Length: variable.
Flags: 1 octet. No flags are currently defined. Flags: 1 octet. No flags are currently defined.
SRv6 Endpoint Function: 2 octets. As defined in SRv6 Endpoint Function: 2 octets. As defined in
[I-D.filsfils-spring-srv6-network-programming] [I-D.ietf-spring-srv6-network-programming]
Legal function values for this sub-TLV are defined in Section 7. Legal function values for this sub-TLV are defined in Section 9.
SID: 16 octets. This field encodes the advertised SRv6 SID. SID: 16 octets. This field encodes the advertised SRv6 SID.
Sub-sub-TLV-length: 1 octet. Number of octets used by sub-sub-TLVs Sub-sub-TLV-length: 1 octet. Number of octets used by sub-sub-TLVs
Optional sub-sub-TLVs Optional sub-sub-TLVs
The SRv6 End SID MUST be a subnet of the associated Locator. SRv6 The SRv6 End SID MUST be a subnet of the associated Locator. SRv6
End SIDs which are NOT a subnet of the associated locator MUST be End SIDs which are NOT a subnet of the associated locator MUST be
ignored. ignored.
Multiple SRv6 End SIDs MAY be associated with the same locator. In Multiple SRv6 End SIDs MAY be associated with the same locator. In
cases where the number of SRv6 End SID sub-TLVs exceeds the capacity cases where the number of SRv6 End SID sub-TLVs exceeds the capacity
of a single TLV, multiple Locator TLVs for the same locator MAY be of a single TLV, multiple Locator TLVs for the same locator MAY be
advertised. For a given MTID/Locator the algorithm MUST be the same advertised. For a given MTID/Locator the algorithm MUST be the same
in all TLVs. If this restriction is not met all TLVs for that MTID/ in all TLVs. If this restriction is not met all TLVs for that MTID/
Locator MUST be ignored. Locator MUST be ignored.
7. Advertising SRv6 End.X SIDs 7. Advertising SRv6 Adjacency SIDs
Certain SRv6 Endpoint functions Certain SRv6 Endpoint functions
[I-D.filsfils-spring-srv6-network-programming] must be associated [I-D.ietf-spring-srv6-network-programming] must be associated with a
with a particular neighbor, and in case of multiple layer 3 links to particular neighbor, and in case of multiple layer 3 links to the
the same neighbor, with a particular link in order to be correctly same neighbor, with a particular link in order to be correctly
applied. applied.
This document defines two new sub-TLVs of TLV 22, 23, 222, 223, and This document defines two new sub-TLVs of TLV 22, 23, 222, 223, and
141 - namely "SRv6 End.X SID" and "SRv6 LAN End.X SID". 141 - namely "SRv6 End.X SID" and "SRv6 LAN End.X SID".
IS-IS Neighbor advertisements are topology specific - but not IS-IS Neighbor advertisements are topology specific - but not
algorithm specific. End.X SIDs therefore inherit the topology from algorithm specific. End.X SIDs therefore inherit the topology from
the associated neighbor advertisement, but the algorithm is specified the associated neighbor advertisement, but the algorithm is specified
in the individual SID. in the individual SID.
skipping to change at page 12, line 40 skipping to change at page 12, line 40
received. received.
Algorithm: 1 octet. Associated algorithm. Algorithm values Algorithm: 1 octet. Associated algorithm. Algorithm values
are defined in the IGP Algorithm Type registry. are defined in the IGP Algorithm Type registry.
Weight: 1 octet. The value represents the weight of the Weight: 1 octet. The value represents the weight of the
End.X SID for the purpose of load balancing. The use End.X SID for the purpose of load balancing. The use
of the weight is defined in [I-D.ietf-spring-segment-routing]. of the weight is defined in [I-D.ietf-spring-segment-routing].
SRv6 Endpoint Function: 2 octets. As defined in SRv6 Endpoint Function: 2 octets. As defined in
[I-D.filsfils-spring-srv6-network-programming] [I-D.ietf-spring-srv6-network-programming]
Legal function values for this sub-TLV are defined in Section 7. Legal function values for this sub-TLV are defined in Section 9.
SID: 16 octets. This field encodes the advertised SRv6 SID. SID: 16 octets. This field encodes the advertised SRv6 SID.
Sub-sub-TLV-length: 1 octet. Number of octets used by sub-sub- Sub-sub-TLV-length: 1 octet. Number of octets used by sub-sub-
TLVs TLVs
Note that multiple TLVs for the same neighbor may be required in Note that multiple TLVs for the same neighbor may be required in
order to advertise all of the SRv6 End.X SIDs associated with that order to advertise all of the SRv6 End.X SIDs associated with that
neighbor. neighbor.
skipping to change at page 14, line 17 skipping to change at page 14, line 17
received. received.
Algorithm: 1 octet. Associated algorithm. Algorithm values Algorithm: 1 octet. Associated algorithm. Algorithm values
are defined in the IGP Algorithm Type registry. are defined in the IGP Algorithm Type registry.
Weight: 1 octet. The value represents the weight of the Weight: 1 octet. The value represents the weight of the
End.X SID for the purpose of load balancing. The use End.X SID for the purpose of load balancing. The use
of the weight is defined in [I-D.ietf-spring-segment-routing]. of the weight is defined in [I-D.ietf-spring-segment-routing].
SRv6 Endpoint Function: 2 octets. As defined in SRv6 Endpoint Function: 2 octets. As defined in
[I-D.filsfils-spring-srv6-network-programming] [I-D.ietf-spring-srv6-network-programming]
Legal function values for this sub-TLV are defined in Section 7. Legal function values for this sub-TLV are defined in Section 9.
SID: 16 octets. This field encodes the advertised SRv6 SID. SID: 16 octets. This field encodes the advertised SRv6 SID.
Sub-sub-TLV-length: 1 octet. Number of octets used by sub-sub- Sub-sub-TLV-length: 1 octet. Number of octets used by sub-sub-
TLVs. TLVs.
8. Advertising Endpoint Behaviors 8. SRv6 SID Structure Sub-Sub-TLV
SRv6 SID Structure Sub-Sub-TLV is an optional Sub-Sub-TLV of:
SRv6 End SID Sub-TLV (Section 6.2)
SRv6 End.X SID Sub-TLV (Section 7.1)
SRv6 LAN End.X SID Sub-TLV (Section 7.2)
SRv6 SID Structure Sub-Sub-TLV is used to advertise the length of
each individual part of the SRv6 SID as defined in
[I-D.ietf-spring-srv6-network-programming]. It has the following
format:
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LB Length | LN Length | Fun. Length | Arg. Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where:
Type: 1
Length: 4 octets.
Flags: 1 octet. No flags are currently defined.
LB Length: 1 octet. SRv6 SID Locator Block length in bits.
LN Length: 1 octet. SRv6 SID Locator Node length in bits.
Fun. Length: 1 octet. SRv6 SID Function length in bits.
Arg. Length: 1 octet. SRv6 SID Arguments length in bits.
ISIS SRv6 SID Structure Sub-Sub-TLV MUST NOT appear more than once in
its parent sub-TLV. If it appears more than once in its parent TLV,
the parent TLV MUST be ignored by the receiver.
9. Advertising Endpoint Behaviors
Endpoint behaviors are defined in Endpoint behaviors are defined in
[I-D.filsfils-spring-srv6-network-programming] and [I-D.ietf-spring-srv6-network-programming] and
[I-D.ali-spring-srv6-oam]. The numerical identifiers for the [I-D.ali-spring-srv6-oam]. The numerical identifiers for the
Endpoint behaviors are defined in the "SRv6 Endpoint Behaviors" Endpoint behaviors are defined in the "SRv6 Endpoint Behaviors"
registry defined in [I-D.filsfils-spring-srv6-network-programming]. registry defined in [I-D.ietf-spring-srv6-network-programming]. This
This section lists the Endpoint behaviors and their identifiers, section lists the Endpoint behaviors and their identifiers, which MAY
which MAY be advertised by IS-IS and the SID sub-TLVs in which each be advertised by IS-IS and the SID sub-TLVs in which each type MAY
type MAY appear. appear.
Endpoint |Endpoint | End | End.X | Lan End.X | Endpoint |Endpoint | End | End.X | Lan End.X |
Behavior |Behavior Identifier | SID | SID | SID | Behavior |Behavior Identifier | SID | SID | SID |
-----------------------|--------------------|-------|-------|-----------| -----------------------|--------------------|-------|-------|-----------|
End (PSP, USP, USD) | 1-4, 28-31 | Y | N | N | End (PSP, USP, USD) | 1-4, 28-31 | Y | N | N |
-----------------------|--------------------|-------|-------|-----------| -----------------------|--------------------|-------|-------|-----------|
End.X (PSP, USP, USD) | 5-8, 32-35 | N | Y | Y | End.X (PSP, USP, USD) | 5-8, 32-35 | N | Y | Y |
-----------------------|--------------------|-------|-------|-----------| -----------------------|--------------------|-------|-------|-----------|
End.T (PSP, USP, USD) | 9-12, 36-39 | Y | N | N | End.T (PSP, USP, USD) | 9-12, 36-39 | Y | N | N |
-----------------------|--------------------|-------|-------|-----------| -----------------------|--------------------|-------|-------|-----------|
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End.DT6 | 18 | Y | N | N | End.DT6 | 18 | Y | N | N |
-----------------------|--------------------|-------|-------|-----------| -----------------------|--------------------|-------|-------|-----------|
End.DT4 | 19 | Y | N | N | End.DT4 | 19 | Y | N | N |
-----------------------|--------------------|-------|-------|-----------| -----------------------|--------------------|-------|-------|-----------|
End.DT64 | 20 | Y | N | N | End.DT64 | 20 | Y | N | N |
-----------------------|--------------------|-------|-------|-----------| -----------------------|--------------------|-------|-------|-----------|
End.OP | 40 | Y | N | N | End.OP | 40 | Y | N | N |
-----------------------|--------------------|-------|-------|-----------| -----------------------|--------------------|-------|-------|-----------|
End.OTP | 41 | Y | N | N | End.OTP | 41 | Y | N | N |
9. IANA Considerations 10. IANA Considerations
This document requests allocation for the following TLVs, sub- TLVs, This document requests allocation for the following TLVs, sub- TLVs,
and sub-sub-TLVs as well updating the ISIS TLV registry and defining and sub-sub-TLVs as well updating the ISIS TLV registry and defining
a new registry. a new registry.
9.1. SRv6 Locator TLV 10.1. SRv6 Locator TLV
This document adds one new TLV to the IS-IS TLV Codepoints registry. This document adds one new TLV to the IS-IS TLV Codepoints registry.
Value: 27 (suggested - to be assigned by IANA) Value: 27 (suggested - to be assigned by IANA)
Name: SRv6 Locator Name: SRv6 Locator
This TLV shares sub-TLV space with existing "Sub-TLVs for TLVs 135, This TLV shares sub-TLV space with existing "Sub-TLVs for TLVs 135,
235, 236 and 237 registry". The name of this registry needs to be 235, 236 and 237 registry". The name of this registry needs to be
changed to "Sub-TLVs for TLVs 27, 135, 235, 236 and 237 registry". changed to "Sub-TLVs for TLVs 27, 135, 235, 236 and 237 registry".
9.1.1. SRv6 End SID sub-TLV 10.1.1. SRv6 End SID sub-TLV
This document adds the following new sub-TLV to the (renamed) "Sub- This document adds the following new sub-TLV to the (renamed) "Sub-
TLVs for TLVs 27, 135, 235, 236 and 237 registry". TLVs for TLVs 27, 135, 235, 236 and 237 registry".
Value: 5 (suggested - to be assigned by IANA) Value: 5 (suggested - to be assigned by IANA)
Name: SRv6 End SID Name: SRv6 End SID
This document requests the creation of a new IANA managed registry This document requests the creation of a new IANA managed registry
for sub-sub-TLVs of the SRv6 End SID sub-TLV. The registration for sub-sub-TLVs of the SRv6 End SID sub-TLV. The registration
procedure is "Expert Review" as defined in [RFC7370]. Suggested procedure is "Expert Review" as defined in [RFC7370]. Suggested
registry name is "sub-sub-TLVs for SRv6 End SID sub-TLV". No sub- registry name is "sub-sub-TLVs for SRv6 End SID sub-TLV". No sub-
sub-TLVs are defined by this document except for the reserved value. sub-TLVs are defined by this document except for the reserved value.
0: Reserved 0: Reserved
1-255: Unassigned 1-255: Unassigned
9.1.2. Revised sub-TLV table 10.1.2. Revised sub-TLV table
The revised table of sub-TLVs for the (renamed) "Sub-TLVs for TLVs The revised table of sub-TLVs for the (renamed) "Sub-TLVs for TLVs
27, 135, 235, 236 and 237 registry" is shown below: 27, 135, 235, 236 and 237 registry" is shown below:
Type 27 135 235 236 237 Type 27 135 235 236 237
1 n y y y y 1 n y y y y
2 n y y y y 2 n y y y y
3 n y y y y 3 n y y y y
4 y y y y y 4 y y y y y
5 y n n n n 5 y n n n n
11 y y y y y 11 y y y y y
12 y y y y y 12 y y y y y
9.2. SRv6 Capabilities sub-TLV 10.2. SRv6 Capabilities sub-TLV
This document adds the definition of a new sub-TLV in the "Sub- TLVs This document adds the definition of a new sub-TLV in the "Sub- TLVs
for TLV 242 registry". for TLV 242 registry".
Type: 25 (Suggested - to be assigned by IANA) Type: 25 (Suggested - to be assigned by IANA)
Description: SRv6 Capabilities Description: SRv6 Capabilities
This document requests the creation of a new IANA managed registry This document requests the creation of a new IANA managed registry
for sub-sub-TLVs of the SRv6 Capability sub-TLV. The registration for sub-sub-TLVs of the SRv6 Capability sub-TLV. The registration
procedure is "Expert Review" as defined in [RFC7370]. Suggested procedure is "Expert Review" as defined in [RFC7370]. Suggested
registry name is "sub-sub-TLVs for SRv6 Capability sub-TLV". No sub- registry name is "sub-sub-TLVs for SRv6 Capability sub-TLV". No sub-
sub-TLVs are defined by this document except for the reserved value. sub-TLVs are defined by this document except for the reserved value.
0: Reserved 0: Reserved
1-255: Unassigned 1-255: Unassigned
9.3. SRv6 End.X SID and SRv6 LAN End.X SID sub-TLVs 10.3. SRv6 End.X SID and SRv6 LAN End.X SID sub-TLVs
This document adds the definition of two new sub-TLVs in the "sub- This document adds the definition of two new sub-TLVs in the "sub-
TLVs for TLV 22, 23, 25, 141, 222 and 223 registry". TLVs for TLV 22, 23, 25, 141, 222 and 223 registry".
Type: 43 (suggested - to be assigned by IANA) Type: 43 (suggested - to be assigned by IANA)
Description: SRv6 End.X SID Description: SRv6 End.X SID
Type: 44 (suggested - to be assigned by IANA) Type: 44 (suggested - to be assigned by IANA)
Description: SRv6 LAN End.X SID Description: SRv6 LAN End.X SID
Type 22 23 25 141 222 223 Type 22 23 25 141 222 223
43 y y y y y y 43 y y y y y y
44 y y y y y y 44 y y y y y y
9.4. MSD Types 10.4. MSD Types
This document defines the following new MSD types. These types are This document defines the following new MSD types. These types are
to be defined in the IGP MSD Types registry defined in to be defined in the IGP MSD Types registry defined in [RFC8491] .
[I-D.ietf-isis-segment-routing-msd] .
All values are suggested values to be assigned by IANA. All values are suggested values to be assigned by IANA.
Type Description Type Description
------------------ ------------------
41 SRH Max SL 41 SRH Max SL
42 SRH Max End Pop 42 SRH Max End Pop
43 SRH Max T.insert 43 SRH Max T.insert
44 SRH Max T.encaps 44 SRH Max T.encaps
45 SRH Max End D 45 SRH Max End D
10. Security Considerations 10.5. Sub-Sub-TLVs for SID Sub-TLVs
This document creates the following Sub-Sub-TLV Registry within the
"IS-IS TLV Codepoints" registry:
Registry: Sub-Sub-TLVs for SID Sub-TLVs
Registration Procedure: Expert review
Reference: This document (Section 6.2, Section 7.1, Section 7.2).
This document defines the following Sub-Sub-TLV in the "Sub-Sub-TLVs
for SID Sub-TLVs" registry:
Type: 1
Description: SRv6 SID Structure Sub-Sub-TLV.
Reference: This document (Section 8).
11. Security Considerations
Security concerns for IS-IS are addressed in [ISO10589], [RFC5304], Security concerns for IS-IS are addressed in [ISO10589], [RFC5304],
and [RFC5310]. and [RFC5310].
11. Contributors 12. Contributors
The following people gave a substantial contribution to the content The following people gave a substantial contribution to the content
of this document and should be considered as co-authors: of this document and should be considered as co-authors:
Stefano Previdi Stefano Previdi
Huawei Technologies Huawei Technologies
Email: stefano@previdi.net Email: stefano@previdi.net
Paul Wells Paul Wells
Cisco Systems Cisco Systems
skipping to change at page 18, line 44 skipping to change at page 20, line 44
Robert Hanzl Robert Hanzl
Cisco Systems Cisco Systems
Millenium Plaza Building, V Celnici 10, Prague 1, Millenium Plaza Building, V Celnici 10, Prague 1,
Prague, Czech Republic Prague, Czech Republic
Email rhanzl@cisco.com Email rhanzl@cisco.com
Ketan Talaulikar Ketan Talaulikar
Cisco Systems, Inc. Cisco Systems, Inc.
Email: ketant@cisco.com Email: ketant@cisco.com
12. References 13. References
12.1. Normative References 13.1. Normative References
[I-D.ali-spring-srv6-oam] [I-D.ali-spring-srv6-oam]
Ali, Z., Filsfils, C., Kumar, N., Pignataro, C., Ali, Z., Filsfils, C., Kumar, N., Pignataro, C.,
faiqbal@cisco.com, f., Gandhi, R., Leddy, J., Matsushima, faiqbal@cisco.com, f., Gandhi, R., Leddy, J., Matsushima,
S., Raszuk, R., daniel.voyer@bell.ca, d., Dawra, G., S., Raszuk, R., daniel.voyer@bell.ca, d., Dawra, G.,
Peirens, B., Chen, M., and G. Naik, "Operations, Peirens, B., Chen, M., and G. Naik, "Operations,
Administration, and Maintenance (OAM) in Segment Routing Administration, and Maintenance (OAM) in Segment Routing
Networks with IPv6 Data plane (SRv6)", draft-ali-spring- Networks with IPv6 Data plane (SRv6)", draft-ali-spring-
srv6-oam-02 (work in progress), October 2018. srv6-oam-02 (work in progress), October 2018.
[I-D.filsfils-spring-srv6-network-programming]
Filsfils, C., Camarillo, P., Leddy, J.,
daniel.voyer@bell.ca, d., Matsushima, S., and Z. Li, "SRv6
Network Programming", draft-filsfils-spring-srv6-network-
programming-07 (work in progress), February 2019.
[I-D.ietf-6man-segment-routing-header] [I-D.ietf-6man-segment-routing-header]
Filsfils, C., Dukes, D., Previdi, S., Leddy, J., Filsfils, C., Dukes, D., Previdi, S., Leddy, J.,
Matsushima, S., and d. daniel.voyer@bell.ca, "IPv6 Segment Matsushima, S., and d. daniel.voyer@bell.ca, "IPv6 Segment
Routing Header (SRH)", draft-ietf-6man-segment-routing- Routing Header (SRH)", draft-ietf-6man-segment-routing-
header-19 (work in progress), May 2019. header-21 (work in progress), June 2019.
[I-D.ietf-isis-segment-routing-extensions] [I-D.ietf-isis-segment-routing-extensions]
Previdi, S., Ginsberg, L., Filsfils, C., Bashandy, A., Previdi, S., Ginsberg, L., Filsfils, C., Bashandy, A.,
Gredler, H., and B. Decraene, "IS-IS Extensions for Gredler, H., and B. Decraene, "IS-IS Extensions for
Segment Routing", draft-ietf-isis-segment-routing- Segment Routing", draft-ietf-isis-segment-routing-
extensions-25 (work in progress), May 2019. extensions-25 (work in progress), May 2019.
[I-D.ietf-isis-segment-routing-msd] [I-D.ietf-spring-srv6-network-programming]
Tantsura, J., Chunduri, U., Aldrin, S., and L. Ginsberg, Filsfils, C., Camarillo, P., Leddy, J.,
"Signaling MSD (Maximum SID Depth) using IS-IS", draft- daniel.voyer@bell.ca, d., Matsushima, S., and Z. Li, "SRv6
ietf-isis-segment-routing-msd-19 (work in progress), Network Programming", draft-ietf-spring-srv6-network-
October 2018. programming-01 (work in progress), July 2019.
[ISO10589] [ISO10589]
Standardization", I. ". O. F., "Intermediate system to Standardization", I. ". O. F., "Intermediate system to
Intermediate system intra-domain routeing information Intermediate system intra-domain routeing information
exchange protocol for use in conjunction with the protocol exchange protocol for use in conjunction with the protocol
for providing the connectionless-mode Network Service (ISO for providing the connectionless-mode Network Service (ISO
8473), ISO/IEC 10589:2002, Second Edition.", Nov 2002. 8473), ISO/IEC 10589:2002, Second Edition.", Nov 2002.
[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,
skipping to change at page 20, line 37 skipping to change at page 22, line 27
[RFC7981] Ginsberg, L., Previdi, S., and M. Chen, "IS-IS Extensions [RFC7981] Ginsberg, L., Previdi, S., and M. Chen, "IS-IS Extensions
for Advertising Router Information", RFC 7981, for Advertising Router Information", RFC 7981,
DOI 10.17487/RFC7981, October 2016, DOI 10.17487/RFC7981, October 2016,
<https://www.rfc-editor.org/info/rfc7981>. <https://www.rfc-editor.org/info/rfc7981>.
[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>.
12.2. Informative References [RFC8491] Tantsura, J., Chunduri, U., Aldrin, S., and L. Ginsberg,
"Signaling Maximum SID Depth (MSD) Using IS-IS", RFC 8491,
DOI 10.17487/RFC8491, November 2018,
<https://www.rfc-editor.org/info/rfc8491>.
13.2. Informative References
[I-D.ietf-spring-segment-routing] [I-D.ietf-spring-segment-routing]
Filsfils, C., Previdi, S., Ginsberg, L., Decraene, B., Filsfils, C., Previdi, S., Ginsberg, L., Decraene, B.,
Litkowski, S., and R. Shakir, "Segment Routing Litkowski, S., and R. Shakir, "Segment Routing
Architecture", draft-ietf-spring-segment-routing-15 (work Architecture", draft-ietf-spring-segment-routing-15 (work
in progress), January 2018. in progress), January 2018.
[RFC8355] Filsfils, C., Ed., Previdi, S., Ed., Decraene, B., and R. [RFC8355] Filsfils, C., Ed., Previdi, S., Ed., Decraene, B., and R.
Shakir, "Resiliency Use Cases in Source Packet Routing in Shakir, "Resiliency Use Cases in Source Packet Routing in
Networking (SPRING) Networks", RFC 8355, Networking (SPRING) Networks", RFC 8355,
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