| Networking Working Group | L. Ginsberg, Ed. |
| Internet-Draft | P. Psenak, Ed. |
| Intended status: Standards Track | C. Filsfils |
| Expires: December 31, 2018 | Cisco Systems |
| A. Bashandy | |
| Individual | |
| B. Decraene | |
| Orange | |
| Z. Hu | |
| Huawei Technologies | |
| June 29, 2018 |
IS-IS Extensions to Support Routing over IPv6 Dataplane
draft-bashandy-isis-srv6-extensions-03.txt
Segment Routing (SR) allows for a flexible definition of end-to-end paths by encoding paths as sequences of topological sub-paths, called "segments". Segment routing architecture can be implemented over an 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 data plane.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.
This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet-Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress."
This Internet-Draft will expire on December 31, 2018.
Copyright (c) 2018 IETF Trust and the persons identified as the document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.
With Segment Routing (SR) [I-D.ietf-spring-segment-routing], a node steers a packet through an ordered list of instructions, called segments.
Segments are identified through Segment Identifiers (SIDs).
Segment Routing can be directly instantiated on the IPv6 data plane through the use of the Segment Routing Header defined in [I-D.ietf-6man-segment-routing-header]. SRv6 refers to this SR instantiation on the IPv6 dataplane.
The network programming paradigm [I-D.filsfils-spring-srv6-network-programming] is central to SRv6. It describes how any function can be bound to a SID and how any network program can be expressed as a combination of SID's.
This document specifies IS-IS extensions that allow the IS-IS protocol to encode some of these functions.
Familiarity with the network programming paradigm [I-D.filsfils-spring-srv6-network-programming] is necessary to understand the extensions specified in this document.
This document defines one new top level IS-IS TLV and several new IS- IS sub-TLVs.
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 summary address for the set of topology/algorithm specific SIDs associated with a node.
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 instantiated at a node and what Endpoint function is bound to each instantiated SID.
A node indicates that it has support for SRv6 by advertising a new SRv6- capabilities sub-TLV of the router capabilities TLV [RFC7981].
The SRv6 Capabilities sub-TLV may contain optional sub-sub-TLVs. No sub-sub-TLVs are currently defined.
The SRv6 Capabilities sub-TLV 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 | Flags |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| optional sub-sub-TLVs...
Type: Suggested value 25, to be assigned by IANA
Length: 2 + length of sub-sub-TLVs
Flags: 2 octets The following flags are defined:
0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |O| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where:
O-flag: If set, the router supports use of the O-bit
in the Segment Routing Header(SRH) as defined in
[I-D.ali-spring-srv6-oam].
[I-D.ietf-isis-segment-routing-msd] defines the means to advertise node/link specific values for Maximum SID Depths (MSD) of various types. Node MSDs are advertised in a sub-TLV of the Router Capabilities TLV [RFC7981]. 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 assignments in the MSD Types registry created by [I-D.ietf-isis-segment-routing-msd].
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 received packet before applying the Endpoint function associated with a SID.
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.
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 USP" as defined in [I-D.filsfils-spring-srv6-network-programming] flavors.
SRH Max End Pop Type: 42 (Suggested value - to be assigned by IANA) If the advertised value is zero or no value is advertised then it is assumed that the router cannot apply PSP or USP flavors.
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 [I-D.filsfils-spring-srv6-network-programming].
SRH Max T.insert Type: 43 (Suggested value - to be assigned by IANA) If the advertised value is zero or no value is advertised then the router is assumed not to support any variation of the "T.insert" behavior.
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 [I-D.filsfils-spring-srv6-network-programming] .
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 only by encapsulating the incoming packet in another IPv6 header without SRH the same way IPinIP encapsulation is performed. If the advertised value is non-zero then the router supports both IPinIP and SRH encapsulation subject to the SID limitation specified by the advertised value.
The Maximum End D MSD Type specifies the maximum number of SIDs in an SRH when performing decapsulation associated with "End.Dx" functions (e.g., "End.DX6" and "End.DT6") as defined in [I-D.filsfils-spring-srv6-network-programming].
SRH Max End D Type: 45 (Suggested value - to be assigned by IANA) If the advertised value is zero or no value is advertised then it is assumed that the router cannot apply "End.DX6" or "End.DT6" functions if the extension header right underneath the outer IPv6 header is an SRH.
As discussed in [I-D.filsfils-spring-srv6-network-programming], an SRv6 Segment Identifier (SID) is 128 bits and represented as
LOC:FUNCT
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 length and is flexible. Each operator is free to use the locator length it chooses.
A node is provisioned with topology/algorithm specific locators for each of the topology/algorithm pairs supported by that node. Each locator is a covering prefix for all SIDs provisioned on that node which have the matching topology/algorithm.
Locators MUST be advertised in the SRv6 Locator TLV (see Section 6.1). Forwarding entries for the locators advertised in the SRv6 Locator TLV MUST be installed in the forwarding plane of receiving SRv6 capable routers when the associated topology/algorithm is supported by the receiving node.
Locators are routable and MAY also be advertised in Prefix Reachability TLVs (236 or 237).
Locators associated with algorithm 0 (for all supported topologies) SHOULD be advertised in a Prefix Reachability TLV (236 or 237) so that legacy routers (i.e., routers which do NOT support SRv6) will install a forwarding entry for algorithm 0 SRv6 traffic.
In cases where a locator advertisement is received in both in a Prefix Reachability TLV and an SRv6 Locator TLV, the Prefix Reachability advertisement MUST be preferred when installing entries in the forwarding plane. This is to prevent inconsistent forwarding entries on SRv6 capable/SRv6 incapable routers.
SRv6 SIDs are advertised as sub-TLVs in the SRv6 Locator TLV except for SRv6 End.X SIDs/LAN End.X SIDs which are associated with a specific Neighbor/Link and are therefore advertised as sub-TLVs in TLVs 22, 23, 222, 223, and 141.
SRv6 SIDs are not directly routable and MUST NOT be installed in the forwarding plane. Reachability to SRv6 SIDs depends upon the existence of a covering locator.
Adherence to the rules defined in this section will assure that SRv6 SIDs associated with a supported topology/algorithm pair will be forwarded correctly, while SRv6 SIDs associated with an unsupported topology/algorithm pair will be dropped. NOTE: The drop behavior depends on the absence of a default/summary route covering a given locator.
In order for forwarding to work correctly, the locator associated with SRv6 SID advertisements MUST be the longest match prefix installed in the forwarding plane for those SIDs. There are a number of ways in which this requirement could be compromised
The SRv6 Locator TLV is introduced to advertise SRv6 Locators and End SIDs associated with each locator.
This new TLV shares the sub-TLV space defined for TLVs 135, 235, 236 and 237.
The SRv6 Locator TLV 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 |R|R|R|R| MTID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Followed by one or more locator entries of the form:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Metric |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | Algorithm |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Loc Size | Locator (variable)...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sub-tlv-len | Sub-TLVs (variable) . . . |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 27 (Suggested value to be assigned by IANA)
Length: variable.
MTID: Multitopology Identifier as defined in [RFC5120].
Note that the value 0 is legal.
Locator entry:
Metric: 4 octets. As described in [RFC5305].
Flags: 1 octet. The following flags are defined
0
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|D| Reserved |
+-+-+-+-+-+-+-+-+
where:
D bit: When the Locator is leaked from level-2 to level-1, the D
bit MUST be set. Otherwise, this bit MUST be clear. Locators
with the D bit set MUST NOT be leaked from level-1 to level-2.
This is to prevent looping.
The remaining bits are reserved for future use. They SHOULD be
set to zero on transmission and MUST be ignored on receipt.
Algorithm: 1 octet. Associated algorithm. Algorithm values
are defined in the IGP Algorithm Type registry.
Loc-Size: 1 octet. Number of bits in the Locator field.
(1 - 128)
Locator: 1-16 octets. This field encodes the advertised SRv6
Locator. The Locator is encoded in the minimal number of
octets for the given number of bits.
Sub-TLV-length: 1 octet. Number of octets used by sub-TLVs
Optional sub-TLVs.
The SRv6 End SID sub-TLV is introduced to advertise SRv6 Segment Identifiers (SID) with Endpoint functions which do not require a particular neighbor in order to be correctly applied [I-D.filsfils-spring-srv6-network-programming]. SRv6 SIDs associated with a neighbor are advertised using the sub-TLVs defined in Section 6.
This new sub-TLV is advertised in the SRv6 Locator TLV defined in the previous section. SRv6 End SIDs inherit the topology/algorithm from the parent locator.
The SRv6 End SID sub-TLV 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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | SRv6 Endpoint Function |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SID (128 bits) . . . |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SID (cont . . .) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SID (cont . . .) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SID (cont . . .) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Sub-sub-tlv-len| sub-sub-TLVs (variable) . . . |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 5 (Suggested value to be assigned by IANA)
Length: variable.
Flags: 1 octet. No flags are currently defined.
SRv6 Endpoint Function: 2 octets. As defined in
[I-D.filsfils-spring-srv6-network-programming]
Legal function values for this sub-TLV are defined in Section 7.
SID: 16 octets. This field encodes the advertised SRv6 SID.
Sub-sub-TLV-length: 1 octet. Number of octets used by sub-sub-TLVs
Optional sub-sub-TLVs
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 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 in all TLVs. If this restriction is not met all TLVs for that MTID/Locator MUST be ignored.
Certain SRv6 Endpoint functions [I-D.filsfils-spring-srv6-network-programming] must be associated with a particular neighbor, and in case of multiple layer 3 links to the same neighbor, with a particular link in order to be correctly applied.
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".
IS-IS Neighbor advertisements are topology specific - but not algorithm specific. End.X SIDs therefore inherit the topology from the associated neighbor advertisement, but the algorithm is specified in the individual SID.
All End.X SIDs MUST be a subnet of a Locator with matching topology and algorithm which is advertised by the same node in an SRv6 Locator TLV. End.X SIDs which do not meet this requirement MUST be ignored.
This sub-TLV is used to advertise an SRv6 SID associated with a point to point adjacency. Multiple SRv6 End.X SID sub-TLVs MAY be associated with the same adjacency.
The SRv6 End.X SID sub-TLV 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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | Algorithm | Weight |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SRv6 Endpoint Function |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SID (128 bits) . . . |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SID (cont . . .) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SID (cont . . .) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SID (cont . . .) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Sub-sub-tlv-len| Sub-sub-TLVs (variable) . . . |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 43 (Suggested value to be assigned by IANA)
Length: variable.
Flags: 1 octet.
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|B|S|P|Reserved |
+-+-+-+-+-+-+-+-+
where:
B-Flag: Backup flag. If set, the End.X SID is eligible
for protection (e.g., using IPFRR) as described in [RFC8355].
S-Flag. Set flag. When set, the S-Flag indicates that the
End.X SID refers to a set of adjacencies (and therefore
MAY be assigned to other adjacencies as well).
P-Flag. Persistent flag. When set, the P-Flag indicates that
the End.X SID is persistently allocated, i.e., the
End.X SID value remains consistent across router restart
and/or interface flap.
Other bits: MUST be zero when originated and ignored when
received.
Algorithm: 1 octet. Associated algorithm. Algorithm values
are defined in the IGP Algorithm Type registry.
Weight: 1 octet. The value represents the weight of the
End.X SID for the purpose of load balancing. The use
of the weight is defined in [I-D.ietf-spring-segment-routing].
SRv6 Endpoint Function: 2 octets. As defined in
[I-D.filsfils-spring-srv6-network-programming]
Legal function values for this sub-TLV are defined in Section 7.
SID: 16 octets. This field encodes the advertised SRv6 SID.
Sub-sub-TLV-length: 1 octet. Number of octets used by sub-sub-
TLVs
This sub-TLV is used to advertise an SRv6 SID associated with a LAN adjacency. Since the parent TLV is advertising an adjacency to the Designated Intermediate System(DIS) for the LAN, it is necessary to include the System ID of the physical neighbor on the LAN with which the SRv6 SID is associated. Given that a large number of neighbors may exist on a given LAN a large number of SRv6 LAN END.X SID sub-TLVs may be associated with the same LAN. Note that multiple TLVs for the same DIS neighbor may be required in order to advertise all of the SRv6 End.X SIDs associated with that neighbor.
The SRv6 LAN End.X SID sub-TLV 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 | System ID (6 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | Algorithm | Weight |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SRv6 Endpoint Function |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SID (128 bits) . . . |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SID (cont . . .) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SID (cont . . .) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SID (cont . . .) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Sub-sub-tlv-len| sub-sub-TLVs (variable) . . . |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 44 (Suggested value to be assigned by IANA)
Length: variable.
System-ID: 6 octets of IS-IS System-ID of length "ID Length" as
defined in [ISO10589].
Flags: 1 octet.
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|B|S|P|Reserved |
+-+-+-+-+-+-+-+-+
where B,S, and P flags are as described in Section 6.1.
Other bits: MUST be zero when originated and ignored when
received.
Algorithm: 1 octet. Associated algorithm. Algorithm values
are defined in the IGP Algorithm Type registry.
Weight: 1 octet. The value represents the weight of the
End.X SID for the purpose of load balancing. The use
of the weight is defined in [I-D.ietf-spring-segment-routing].
SRv6 Endpoint Function: 2 octets. As defined in
[I-D.filsfils-spring-srv6-network-programming]
Legal function values for this sub-TLV are defined in Section 7.
SID: 16 octets. This field encodes the advertised SRv6 SID.
Sub-sub-TLV-length: 1 octet. Number of octets used by sub-sub-
TLVs.
Endpoint function types are defined in [I-D.filsfils-spring-srv6-network-programming]. The numerical values are defined in the "SRv6 Endpoint Types" registry defined in [I-D.filsfils-spring-srv6-network-programming]. This section lists the Endpoint function types which MAY be advertised by IS-IS and the SID sub-TLVs in which each type MAY appear.
Endpoint | End | End.X | Lan End.X | Function Type | SID | SID | SID | ----------------------|-------|-------|-----------| End(no PSP, no USP) | Y | N | N | ----------------------|-------|-------|-----------| End(with PSP) | Y | N | N | ----------------------|-------|-------|-----------| End(with USP) | Y | N | N | ----------------------|-------|-------|-----------| End(with PSP & USP) | Y | N | N | ----------------------|-------|-------|-----------| End.T(no PSP, no USP) | Y | N | N | ----------------------|-------|-------|-----------| End.T(with PSP) | Y | N | N | ----------------------|-------|-------|-----------| End.T(with USP) | Y | N | N | ----------------------|-------|-------|-----------| End.T(with PSP & USP) | Y | N | N | ----------------------|-------|-------|-----------| End.X(no PSP, no USP) | N | Y | Y | ----------------------|-------|-------|-----------| End.X(with PSP) | N | Y | Y | ----------------------|-------|-------|-----------| End.X(with USP) | N | Y | Y | ----------------------|-------|-------|-----------| End.X(with PSP & USP) | N | Y | Y | ----------------------|-------|-------|-----------| End.DX6 | N | Y | Y | ----------------------|-------|-------|-----------| End.DT6 | Y | N | N | ----------------------|-------|-------|-----------| End.OTP | Y | N | N |
This document requests allocation for the following TLVs, sub- TLVs, and sub-sub-TLVs as well updating the ISIS TLV registry and defining a new registry.
This document adds one new TLV to the IS-IS TLV Codepoints registry.
Value: 27 (suggested - to be assigned by IANA)
Name: SRv6 Locator
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 changed to "Sub-TLVs for TLVs 27, 135, 235, 236 and 237 registry".
This document adds the following new sub-TLV to the (renamed) "Sub-TLVs for TLVs 27, 135, 235, 236 and 237 registry".
Value: 5 (suggested - to be assigned by IANA)
Name: SRv6 End SID
This document requests the creation of a new IANA managed registry for sub-sub-TLVs of the SRv6 End SID sub-TLV. The registration procedure is "Expert Review" as defined in [RFC7370]. Suggested 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.
0: Reserved
1-255: Unassigned
The revised table of sub-TLVs for the (renamed) "Sub-TLVs for TLVs 27, 135, 235, 236 and 237 registry" is shown below:
Type 27 135 235 236 237 1 n y y y y 2 n y y y y 3 n y y y y 4 y y y y y 5 y n n n n 11 y y y y y 12 y y y y y
This document adds the definition of a new sub-TLV in the "Sub- TLVs for TLV 242 registry".
Type: 25 (Suggested - to be assigned by IANA)
Description: SRv6 Capabilities
This document requests the creation of a new IANA managed registry for sub-sub-TLVs of the SRv6 Capability sub-TLV. The registration procedure is "Expert Review" as defined in [RFC7370]. Suggested 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.
0: Reserved
1-255: Unassigned
This document adds the definition of two new sub-TLVs in the "sub- TLVs for TLV 22, 23, 25, 141, 222 and 223 registry".
Type: 43 (suggested - to be assigned by IANA)
Description: SRv6 End.X SID
Type: 44 (suggested - to be assigned by IANA)
Description: SRv6 LAN End.X SID
Type 22 23 25 141 222 223 43 y y y y y y 44 y y y y y y
This document defines the following new MSD types. These types are to be defined in the IGP MSD Types registry defined in [I-D.ietf-isis-segment-routing-msd] .
All values are suggested values to be assigned by IANA.
Type Description ------------------ 41 SRH Max SL 42 SRH Max End Pop 43 SRH Max T.insert 44 SRH Max T.encaps 45 SRH Max End D
Security concerns for IS-IS are addressed in [ISO10589], [RFC5304], and [RFC5310].
The following people gave a substantial contribution to the content of this document and should be considered as co-authors:
Stefano Previdi Huawei Technologies Email: stefano@previdi.net Paul Wells Cisco Systems Saint Paul, Minnesota United States Email: pauwells@cisco.com Daniel Voyer Email: daniel.voyer@bell.ca Satoru Matsushima Email: satoru.matsushima@g.softbank.co.jp Bart Peirens Email: bart.peirens@proximus.com Hani Elmalky Email: hani.elmalky@ericsson.com Prem Jonnalagadda Email: prem@barefootnetworks.com Milad Sharif Email: msharif@barefootnetworks.com> Robert Hanzl Cisco Systems Millenium Plaza Building, V Celnici 10, Prague 1, Prague, Czech Republic Email rhanzl@cisco.com Ketan Talaulikar Cisco Systems, Inc. Email: ketant@cisco.com
| [I-D.ietf-spring-segment-routing] | Filsfils, C., Previdi, S., Ginsberg, L., Decraene, B., Litkowski, S. and R. Shakir, "Segment Routing Architecture", Internet-Draft draft-ietf-spring-segment-routing-15, January 2018. |
| [RFC8355] | Filsfils, C., Previdi, S., Decraene, B. and R. Shakir, "Resiliency Use Cases in Source Packet Routing in Networking (SPRING) Networks", RFC 8355, DOI 10.17487/RFC8355, March 2018. |