Huawei

Huawei Bld., No.156 Beiqing Rd. Beijing 100095 China lichenxi1@huawei.com

Huawei

Huawei Bld., No. 156 Beiqing Rd. Beijing 100095 China xuguoqi@huawei.com

Huawei

Huawei Bld., No.156 Beiqing Rd. Beijing 100095 China huzhibo@huawei.com

In certain networks, network-performance criteria (e.g., latency) are becoming as critical to data-path selection as other metrics. This document describes extensions to IS-IS Traffic Engineering (TE) Metric Extensions (RFC 8570) for LAN subnetworks. These extensions provide a way to distribute and collect network-performance information in LAN subnetworks. The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD 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.

In certain networks, network-performance criteria (e.g., latency) are becoming as critical to data-path selection as other metrics. This document describes extensions to IS-IS Traffic Engineering (TE) Metric Extensions (RFC 8570) for LAN subnetworks. These extensions provide a way to distribute and collect network-performance information in LAN subnetworks. In LAN subnetworks, the Designated Intermediate System (DIS) is elected and originates the Pseudonode LSP (PN LSP) including all neighbors of the DIS. Since, on LANs, each router only advertises one adjacency to the DIS (and doesn't advertise any other adjacency), each router should advertise the TE metric for each of its neighbors. Since the parent TLV is advertising an adjcacency to the DIS, it is necessary to include the System ID of the physical neighbor in each TE LAN Sub-TLV.

This document registers new IS-IS TE sub-TLVs in the "Sub-TLVs for TLVs 22, 23, 141, 222, and 223" registry. These new sub-TLVs provides ways to distribute network-performance information in LAN subnetworks. This document registers new sub-TLVs:

This sub-TLV advertises the average link delay between two real connected IS-IS neighbors in LAN. Each router advertises the average link delay for each of its neighbors inside a newly defined sub-TLV that is a part of the TLV advertising the adjacency to the DIS (e.g., TLV-22). The format of this sub-TLV is shown in the following diagram:

Type: TBD (suggested value 41) is to be assigned by IANA. Length: 4 + System-ID length. Neighbor System-ID: IS-IS System-ID of length "ID Length" as defined in [ISO10589]. The other fields are the same as defined in [RFC8570] for Unidirectional Link Delay Sub-TLV. This sub-TLV is optional. This sub-TLV SHOULD appear only once in each parent TLV.

This sub-TLV advertises the minimum and maximum delay values between two real connected IS-IS neighbors in LAN. Each router advertises the minimum and maximum delay for each of its neighbors inside a newly defined sub-TLV that is a part of the TLV advertising the adjacency to the DIS (e.g., TLV-22). The format of this sub-TLV is shown in the following diagram:

Type: TBD (suggested value 42) is to be assigned by IANA. Length: 8 + System-ID length. Neighbor System-ID: IS-IS System-ID of length "ID Length" as defined in [ISO10589]. The other fields are the same as defined in [RFC8570] for Min/Max Unidirectional Link Delay Sub-TLV. This sub-TLV is optional. This sub-TLV SHOULD appear only once in each parent TLV.

This sub-TLV advertises the average link delay variation between two real connected IS-IS neighbors in LAN. Each router advertises average link delay variation for each of its neighbors inside a newly defined sub-TLV that is a part of the TLV advertising the adjacency to the DIS (e.g., TLV-22). The format of this sub-TLV is shown in the following diagram:

Type: TBD (suggested value 43) is to be assigned by IANA. Length: 4 + System-ID length. Neighbor System-ID: IS-IS System-ID of length "ID Length" as defined in [ISO10589]. The other fields are the same as defined in [RFC8570] for Unidirectional Delay Variation Sub-TLV. This sub-TLV is optional. This sub-TLV SHOULD appear only once in each parent TLV.

This sub-TLV advertises the loss (as a packet percentage) between two real connected IS-IS neighbors in LAN. Each router advertises the link loss for each of its neighbors inside a newly defined sub-TLV that is a part of the TLV advertising the adjacency to the DIS (e.g., TLV-22). The format of this sub-TLV is shown in the following diagram:

Type: TBD (suggested value 44) is to be assigned by IANA. Length: 4 + System-ID length. Neighbor System-ID: IS-IS System-ID of length "ID Length" as defined in [ISO10589]. The other fields are the same as defined in [RFC8570] for Unidirectional Link Loss Sub-TLV. This sub-TLV is optional. This sub-TLV SHOULD appear only once in each parent TLV.

This sub-TLV advertises the residual bandwidth between two real connected IS-IS neighbors in LAN. Each router advertises the residual bandwidth for each of its neighbors inside a newly defined sub-TLV that is a part of the TLV advertising the adjacency to the DIS (e.g., TLV-22). The format of this sub-TLV is shown in the following diagram:

Type: TBD (suggested value 45) is to be assigned by IANA. Length: 4 + System-ID length. Neighbor System-ID: IS-IS System-ID of length "ID Length" as defined in [ISO10589]. The other fields are the same as defined in [RFC8570] for Unidirectional Residual Bandwidth Sub-TLV. This sub-TLV is optional. This sub-TLV SHOULD appear only once in each parent TLV.

This sub-TLV advertises the available bandwidth between two real connected IS-IS neighbors in LAN. Each router advertises the available bandwidth for each of its neighbors inside a newly defined sub-TLV that is a part of the TLV advertising the adjacency to the DIS (e.g., TLV-22). The format of this sub-TLV is shown in the following diagram:

Type: TBD (suggested value 46) is to be assigned by IANA. Length: 4 + System-ID length. Neighbor System-ID: IS-IS System-ID of length "ID Length" as defined in [ISO10589]. The other fields are the same as defined in [RFC8570] for Unidirectional Available Bandwidth Sub-TLV. This sub-TLV is optional. This sub-TLV SHOULD appear only once in each parent TLV.

This sub-TLV advertises the bandwidth utilization between two real connected IS-IS neighbors in LAN. Each router advertises the bandwidth utilization (for each of its neighbors) inside a newly defined sub-TLV that is a part of the TLV advertising the adjacency to the DIS (e.g., TLV-22). The format of this sub-TLV is shown in the following diagram:

Type: TBD (suggested value 47) is to be assigned by IANA. Length: 4 + System-ID length. Neighbor System-ID: IS-IS System-ID of length "ID Length" as defined in [ISO10589]. The other fields are the same as defined in [RFC8570] for Unidirectional Utilized Bandwidth Sub-TLV. This sub-TLV is optional. This sub-TLV SHOULD appear only once in each parent TLV.

This document uses the same principle for announcement thresholds and filters as described in RFC 8570.

This document uses the same principle for announcement suppression as described in RFC 8570.

This document uses the same principle for network stability and announcement periodicity as described in RFC 8570.

Implementations MUST make it possible to enable or disable each sub-TLV based on configuration.

Unrecognized sub-TLVs should be silently ignored.

TBD.

This document requests that IANA allocates new sub-TLV types from the "Sub-TLVs for TLVs 22, 23, 25, 141, 222, and 223 (Extended IS reachability, IS Neighbor Attribute, L2 Bundle Member Attributes, inter-AS reachability information, MT-ISN, and MT IS Neighbor Attribute TLVs)" registry as specified.

These extensions to IS-IS do not add any new security issues to the existing IGP.