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RFC 9999isis l2bundlesJuly 2019
Ginsberg, et al.Standards Track[Page]
Stream:
Internet Engineering Task Force (IETF)
RFC:
9999
Category:
Standards Track
Published:
ISSN:
2070-1721
Authors:
L. Ginsberg
Cisco Systems
A. Bashandy
Cisco Systems
C. Filsfils
Cisco Systems
M. Nanduri
eBay
E. Aries
Private Contributer

Advertising L2 Bundle Member Link Attributes in IS-IS

Abstract

There are deployments where the Layer 3 interface on which IS-IS operates is a Layer 2 interface bundle. Existing IS-IS advertisements only support advertising link attributes of the Layer 3 interface. If entities external to IS-IS wish to control traffic flows on the individual physical links which comprise the Layer 2 interface bundle link attribute information about the bundle members is required.

This document introduces the ability for IS-IS to advertise the link attributes of layer 2 (L2) bundle members.

Requirements Language

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.

Status of This Memo

This is an Internet Standards Track document.

This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 7841.

Information about the current status of this document, any errata, and how to provide feedback on it may be obtained athttps://www.rfc-editor.org/info/rfc9999.

Copyright Notice

Copyright (c) 2019 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.

Table of Contents

1. Introduction

There are deployments where the Layer 3 interface on which an IS-IS adjacency is established is a Layer 2 interface bundle, for instance a Link Aggregation Group (LAG)[IEEE802.1AX]. This reduces the number of adjacencies which need to be maintained by the routing protocol in cases where there are parallel links between the neighbors. Entities external to IS-IS such as Path Computation Elements (PCE)[RFC4655] may wish to control traffic flows on individual members of the underlying Layer 2 bundle. In order to do so link attribute information about individual bundle members is required. The protocol extensions defined in this document provide the means to advertise this information.

This document introduces a new TLV to advertise link attribute information for each of the L2 bundle members which comprise the Layer 3 interface on which IS-IS operates.

[SR-ISIS] introduces a new link attribute - adjacency segment identifier (Adj-SID) - which can be used as an instruction to forwarding to send traffic over a specific link. This document introduces additional sub-TLVs to advertise Adj-SIDs for L2 Bundle members.

Note that the new advertisements defined in this document are intended to be provided to external (to IS-IS) entities. The following items are intentionally not defined and/or are outside the scope of this document:

2. L2 Bundle Member Attributes TLV

A new TLV is introduced to advertise L2 Bundle member attributes. Although much of the information is identical to and uses the same sub-TLVs included in Extended IS-Neighbor advertisements (TLVs 22 and 222), a new TLV is used so that changes to the advertisement of the L2 Bundle member link attributes does not trigger unnecessary action by the[ISO10589] Decision process.

Advertisement of this information implies that the identified link is a member of the L2 Bundle associated with the identified Parent L3 Neighbor and that the member link is operationally up. Therefore advertisementsMUST be withdrawn if the link becomes operationally down or it is no longer a member of the identified L2 Bundle.

This new TLV utilizes the sub-TLV space defined for TLVs 22, 23, 141, 222, and 223.

The following new TLV is introduced:

NOTE: Only one Parent L3 Neighbor Descriptor is present in a given TLV. Multiple L2 Bundle Attribute Descriptors may be present in a single TLV.

2.1. Parallel L3 Adjacencies

When there exist multiple L3 adjacencies to the same neighbor additional information is required to uniquely identify the L3 Neighbor. One and only one of the following three sub-TLVs is used to uniquely identify the L3 adjacency:

When the P-bit is set in the flags field in the Parent L3 Neighbor Descriptor one and only one of the above sub-TLVsMUST be present. The chosen sub-TLVMUST immediately follow the flags field described in Section 2.

These sub-TLVsMAY be omitted if no parallel adjacencies to the neighbor exist.

2.2. Shared Attribute sub-TLVs

These sub-TLVs advertise a single copy of an attribute (e.g. link bandwidth). The attribute applies to all of the L2 Bundle Members in the set advertised under the preceding  L2 Bundle Member Attribute Descriptor. No more than one copy of a given sub-TLV in this category may appear in the set of sub-TLVs under the preceding L2 Bundle Member Attribute Descriptor. If multiple copies of a given sub-TLV are present all copiesMUST be ignored.

The set of L2 Bundle Member Descriptors which may be advertised under a single L2 Bundle Member Attribute Descriptor is therefore limited to bundle members which share the set of attributes advertised in the shared attribute sub-TLVs.

All existing sub-TLVs defined in the IANA Sub-TLVs for TLVs 22, 23, 141, 222, and 223 registry are in the category of shared attribute sub-TLVs unless otherwise specified in this document.

3. Advertising L2 Bundle Member Adj-SIDs

[SR-ISIS] defines sub-TLVs to advertise Adj-SIDs for L3 adjacencies. However these sub-TLVs only support a advertisement of a single Adj-SID. As it is expected that each L2 Bundle member will have unique Adj-SIDs in many deployments it is desirable to define a new sub-TLV which allows more efficient encoding of a set of Adj-SIDs in a single sub-TLV. Two new sub-TLVs are therefore introduced to support advertising Adj-SIDs for L2 Bundle members. The format of the new sub-TLVs is similar to that used for L3 adjacencies, but is optimized to allow advertisement of a set of Adj-SIDs (one per L2 Bundle Member) in a single sub-TLV.

The two new sub-TLVs defined in the following sections do not fall into the category of shared attribute sub-TLVs.

3.1. L2 Bundle Member Adjacency Segment Identifier sub-TLV

This sub-TLV is used to advertise Adj-SIDs for L2 Bundle Members associated with a parent L3 adjacency which is Point-to-Point. The following format is defined for this sub-TLV:

NOTE: The flags are deliberately kept congruent to the flags in the L3 ADJ-SID defined in[SR-ISIS]. * indicates a flag used in the L3 Adj-SID sub-TLV but which is NOT used in this sub-TLV. These bitsSHOULD be sent as 0 andMUST be ignored on receipt.

Weight:
1 octet. The value represents the weight of the Adj-SID for the purpose of load balancing. The use of the weight is defined in[RFC8402].

NOTE: Flags and weight are shared by all L2 Bundle Members listed in the L2 Bundle Attribute Descriptor.

L2 Bundle Member Adj-SID Descriptors.

ThereMUST be one descriptor for each of the L2 Bundle Members advertised under the preceding L2 Bundle Member Attribute Descriptor. Each descriptor consists of one of the following fields:

SID/Index/Label:

according to the V and L flags, it contains either:

  • A 3 octet local label where the 20 rightmost bits are used for encoding the label value. In this case the V and L flagsMUST be set.
  • A 4 octet index defining the offset in the SID/Label space advertised by this router. See[SR-ISIS]. In this case V and L flagsMUST be unset.

3.2. L2 Bundle Member LAN Adjacency Segment Identifier sub-TLV

This sub-TLV is used to advertise Adj-SIDs for L2 Bundle Members associated with a parent L3 adjacency which is a LAN adjacency. In LAN subnetworks, the Designated Intermediate System (DIS) is elected and originates the Pseudonode-LSP (PN-LSP) including all neighbors of the DIS. When Segment Routing is used, each router in the LANMAY advertise the Adj-SID of each of its neighbors on the LAN. Similarly, for each L2 Bundle Member a routerMAY advertise an Adj-SID to each neighbor on the LAN.

The following format is defined for this sub-TLV:

Type: 42 (suggested value to be assigned by IANA) (1 octet)

Length: variable (1 octet)

Neighbor System ID: 6 octets

NOTE: The flags are deliberately kept congruent to the flags in the L3 LAN_ADJ-SID defined in[SR-ISIS]. * indicates a flag used in the L3 Adj-SID sub-TLV but which is NOT used in this sub-TLV. These bitsSHOULD be sent as 0 andMUST be ignored on receipt.

Weight:
1 octet. The value represents the weight of the Adj-SID for the purpose of load balancing. The use of the weight is defined in[RFC8402].

NOTE: Flags and weight are shared by all L2 Bundle Members listed in the L2 Bundle Attribute Descriptor.

L2 Bundle Member LAN Adj-SID Descriptors.

ThereMUST be one descriptor for each of the L2 Bundle Members advertised under the preceding L2 Bundle Member Attribute Descriptor. Each descriptor consists of one of the following fields:

SID/Index/Label:

according to the V and L flags, it contains either:

  • A 3 octet local label where the 20 rightmost bits are used for encoding the label value. In this case the V and L flagsMUST be set.
  • A 4 octet index defining the offset in the SID/Label space advertised by this router. See[SR-ISIS]. In this case V and L flagsMUST be unset.

4. IANA Considerations

This document adds the following new TLV to the IS-IS TLV Codepoints registry.

The name of the Sub-TLVs for TLVs 22, 23, 141, 222, and 223 registry needs to be changed to Sub-TLVs for TLVs 22, 23, 25, 141, 222, and 223 registry. An additional column needs to be added to the registry to indicate which sub-TLVs may appear in the new L2 Bundle Member Attributes TLV. The column for TLV 25 has one of the following three values:

y:
sub-TLV may appear in TLV 25 butMUST NOT be shared by multiple L2 Bundle Members
y(s):
sub-TLV may appear in TLV 25 andMAY be shared by multiple L2 Bundle Members
n:
sub-TLVMUST NOT appear in TLV 25

The following table indicates the appropriate settings for all currently defined sub-TLVs as regards their use in the new L2 Bundle Member Attributes TLV.

Table 1:Appropriate Settings for All Defined Sub-TLVs as regards their use inthe new L2 Bundle Member Attributes TLV
TypeDescription25
3Administrative group (color)y(s)
4Link Local/Remote Identifiersy(s)
6IPv4 interface addressy(s)
8IPv4 neighbor addressy(s)
9Maximum link bandwidthy(s)
10Maximum reservable link bandwidthy(s)
11Unreserved bandwidthy(s)
12IPv6 Interface Addressy(s)
13IPv6 Neighbor Addressy(s)
14Extended Administrative Groupy(s)
18TE Default metricy(s)
19Link-attributesy(s)
20Link Protection Typey(s)
21Interface Switching Capability Descriptory(s)
22Bandwidth Constraintsy(s)
23Unconstrained TE LSP County(s)
24Remote AS numbern
25IPv4 remote ASBR Identifiern
26IPv6 remote ASBR Identifiern
27Interface Adjustment Capability Descriptor (IACD)y(s)
28MTU nn
29SPB-Metricy(s)
30SPB-A-OALGy(s)
33Unidirectional Link Delayy
34Min/Max Unidirectional Link Delayy
35Unidirectional Delay Variationy
36Unidirectional Link Lossy
37Unidirectional Residual Bandwidthy
38Unidirectional Available Bandwidthy
39Unidirectional Utilized Bandwidthy
40RTM Capabilityn

This document adds the following new sub-TLVs to the sub-TLVs for TLVs 22, 23, 25, 141, 222, and 223 registry.

Table 2
222325141222223
nnynnn
Table 3
222325141222223
nnynnn

5. Security Considerations

The IS-IS protocol has supported the advertisement of link attribute information, including link identifiers, for many years. The advertisements defined in this document are identical to existing advertisements defined in[RFC4202],[RFC5305],[RFC7810], and[SR-ISIS] - but are associated with L2 links which are part of a bundle interface on which the IS-IS protocol operates. There are therefore no new security issues introduced by the extensions in this document.

As always, if the protocol is used in an environment where unauthorized access to the physical links on which IS-IS PDUs are sent occurs then attacks are possible. The use of authentication as defined in[RFC5304] and[RFC5310] is recommended to prevent such attacks.

6. Contributors

The following people gave a substantial contribution to the content of this document and should be considered as co-authors:

Stefano PrevidiCisco SystemsVia Del Serafico 200Rome  0144ItalyEmail: sprevidi@cisco.com

7. Acknowledgements

The authors would like to thank Jon Mitchell for his careful review.

8. References

8.1. Normative References

[IEEE802.1AX]
IEEE,"IEEE Standard for Local and Metropolitan Area Networks - Link Aggregation.",.
[ISO10589]
ISO,"Intermediate system to Intermediate system intra-domain routeing information exchange protocol for use in conjunction with the protocol for providing the connectionless-mode Network Service (ISO 8473)",ISO/IEC 10589:2002, Second Edition,.
[RFC2119]
Bradner, S.,"Key words for use in RFCs to Indicate Requirement Levels",BCP 14,RFC 2119,DOI 10.17487/RFC2119,,<https://www.rfc-editor.org/info/rfc2119>.
[RFC4202]
Kompella, K., Ed. and Y. Rekhter, Ed.,"Routing Extensions in Support of Generalized Multi-Protocol Label Switching (GMPLS)",RFC 4202,DOI 10.17487/RFC4202,,<https://www.rfc-editor.org/info/rfc4202>.
[RFC5304]
Li, T. and R. Atkinson,"IS-IS Cryptographic Authentication",RFC 5304,DOI 10.17487/RFC5304,,<https://www.rfc-editor.org/info/rfc5304>.
[RFC5305]
Li, T. and H. Smit,"IS-IS Extensions for Traffic Engineering",RFC 5305,DOI 10.17487/RFC5305,,<https://www.rfc-editor.org/info/rfc5305>.
[RFC5307]
Kompella, K., Ed. and Y. Rekhter, Ed.,"IS-IS Extensions in Support of Generalized Multi-Protocol Label Switching (GMPLS)",RFC 5307,DOI 10.17487/RFC5307,,<https://www.rfc-editor.org/info/rfc5307>.
[RFC5310]
Bhatia, M., Manral, V., Li, T., Atkinson, R., White, R., and M. Fanto,"IS-IS Generic Cryptographic Authentication",RFC 5310,DOI 10.17487/RFC5310,,<https://www.rfc-editor.org/info/rfc5310>.
[RFC6119]
Harrison, J., Berger, J., and M. Bartlett,"IPv6 Traffic Engineering in IS-IS",RFC 6119,DOI 10.17487/RFC6119,,<https://www.rfc-editor.org/info/rfc6119>.
[RFC7810]
Previdi, S., Ed., Giacalone, S., Ward, D., Drake, J., and Q. Wu,"IS-IS Traffic Engineering (TE) Metric Extensions",RFC 7810,DOI 10.17487/RFC7810,,<https://www.rfc-editor.org/info/rfc7810>.
[RFC8174]
Leiba, B.,"Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words",BCP 14,RFC 8174,DOI 10.17487/RFC8174,,<https://www.rfc-editor.org/info/rfc8174>.
[SR-ISIS]
Previdi, S., Ginsberg, L., Filsfils, C., Bashandy, A., Gredler, H., and B. Decraene,"IS-IS Extensions for Segment Routing",Work in Progress,Internet-Draft, draft-ietf-isis-segment-routing-extensions-25,,<https://tools.ietf.org/html/draft-ietf-isis-segment-routing-extensions-25.txt>.

8.2. Informational References

[RFC4655]
Farrel, A., Vasseur, J.-P., and J. Ash,"A Path Computation Element (PCE)-Based Architecture",RFC 4655,DOI 10.17487/RFC4655,,<https://www.rfc-editor.org/info/rfc4655>.
[RFC8402]
Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L., Decraene, B., Litkowski, S., and R. Shakir,"Segment Routing Architecture",RFC 8402,DOI 10.17487/RFC8402,,<https://www.rfc-editor.org/info/rfc8402>.

Appendix A. Example Encoding

Below is an example encoding of L2 Bundle advertisements in a case where we have two parallel adjacencies to the same neighbor whose system-id is 1234.1234.1234.00. The two L2 bundles have the following sets of attributes:

L3 Adjacency #1

L3 IPv4 local link address: 192.0.2.1

Four bundle members with the following attributes:

Table 4
NumLink Local IDBandwidthAdj-SID/Weight
10x111111111G0x11111/1
20x111122221G0x11112/1
30x1111333310G0x11113/1
40x1111444410G0x11114/1

L3 Adjacency #2

L3 IPv4 local link address: 192.0.2.2

Three bundle members with the following attributes:

Table 5
NumLink Local IDBandwidthAdj-SID/Weight
10x2222111110G22221/1
20x2222222210G22222/1
30x2222333310G22223/1

This requires two TLVs, one for each L3 adjacency.

TLV for Adjacency #1:

 0                   1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+|  Type(25)     |Len: 64        |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Parent L3 Neighbor Descriptor

 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  | Neighbor System-ID octets 1-4: 1234.1234                      |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  | System-ID octets 5-6: 1234    | P-node: 00    |1|0|0|0|0|0|0|0|+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

IPv4 Interface Address sub-TLV

 0                   1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+|  Type(6))     | Length(4)     |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  | IPv4 address:192.0.2.1                                          |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

L2 Bundle Attribute Descriptors

 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+|Len:9+6+10 = 25| # Desc: 2     |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  | Link Local Identifier Bundle Member #1: 0x11111111            |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| Link Local Identifier Bundle Member #2: 0x11112222            |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Maximum Link Bandwidth sub-TLV

 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(9)       | Length(4)    |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  | Bandwidth Value: 1G/8                                         |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

L2 Bundle Member Adjacency Segment Identifier sub-TLV

 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(41)     | Length(8)     |0|0|1|1|0|0|0|0| Weight: 1     |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| Local Label Bundle Member #1: 0x11111         |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| Local Label Bundle Member #2: 0x11112         |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

L2 Bundle Attribute Descriptors

 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+|Len:9+6+10 = 25| # Desc: 2     |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  | Link Local Identifier Bundle Member #3: 0x11113333            |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| Link Local Identifier Bundle Member #4: 0x11114444            |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Maximum Link Bandwidth sub-TLV

 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(9)       | Length(4)    |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  | Bandwidth Value: 10G/8                                        |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

L2 Bundle Member Adjacency Segment Identifier sub-TLV

 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(41)     | Length(8)     |0|0|1|1|0|0|0|0| Weight: 1     |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| Local Label Bundle Member #3: 0x11113         |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| Local Label Bundle Member #4: 0x11114         |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

TLV for Adjacency #2

0                   1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+|  Type(25)     | Len: 46       |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Parent L3 Neighbor Descriptor

 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  | Neighbor System-ID octets 1-4: 1234.1234                      |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  | System-ID octets 5-6: 1234    | P-node: 00    |1|0|0|0|0|0|0|0|+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

IPv4 Interface Address sub-TLV

 0                   1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+|  Type(6))     | Length(4)     |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  | IPv4 address: 192.0.2.2                                         |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

L2 Bundle Attribute Descriptors

 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+|Len:13+6+13=32 | # Desc: 3     |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  | Link Local Identifier Bundle Member #1: 0x22221111            |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| Link Local Identifier Bundle Member #2: 0x22222222            |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| Link Local Identifier Bundle Member #3: 0x22223333            |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Maximum Link Bandwidth sub-TLV

 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(9)       | Length(4)    |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  | Bandwidth Value: 10G/8                                        |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

L2 Bundle Member Adjacency Segment Identifier sub-TLV

 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(41)     | Length(11)    |0|0|1|1|0|0|0|0| Weight: 1     |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| Local Label Bundle Member #1: 0x22221         |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| Local Label Bundle Member #2: 0x22222         |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| Local Label Bundle Member #3: 0x22223         |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Authors' Addresses

Les Ginsberg
Cisco Systems
510 McCarthy Blvd.
Milpitas,CA95035
United States of America
Email:ginsberg@cisco.com
Ahmed Bashandy
Cisco Systems
170 West Tasman Drive
San Jose,Ca95134
United States of America
Clarence Filsfils
Cisco Systems
Email:cf@cisco.com
Mohan Nanduri
eBay
Email:mnanduri@ebay.com
Ebben Aries
Private Contributer
Email:exa@dscp.org

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