Dell Configuration Guide for the S4048–ON System 9.14.2.5

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Configuring the IS-IS Metric Style

All IS-IS links or interfaces are associated with a cost that is used in the shortest path first (SPF) calculations. The possible cost varies depending on the metric style supported.

If you configure narrow, transition, or narrow transition metric style, the cost can be a number between 0 and 63. If you configure wide or wide transition metric style, the cost can be a number between 0 and 16,777,215. Dell EMC Networking OS supports five different metric styles: narrow, wide, transition, narrow transition, and wide transition.

By default, Dell EMC Networking OS generates and receives narrow metric values. Matrixes or costs higher than 63 are not supported. To accept or generate routes with a higher metric, you must change the metric style of the IS-IS process. For example, if you configure the metric as narrow, and a link state PDU (LSP) with wide metrics is received, the route is not installed.

Dell EMC Networking OS supports the following IS-IS metric styles.

Table 1. Metric StylesStyles
Metric Style	Characteristics	Cost Range Supported on IS-IS Interfaces
narrow	Sends and accepts narrow or old TLVs (Type, Length, Value).	0 to 63
wide	Sends and accepts wide or new TLVs.	0 to 16777215
transition	Sends both wide (new) and narrow (old) TLVs.	0 to 63
narrow transition	Sends narrow (old) TLVs and accepts both narrow (old) and wide (new) TLVs.	0 to 63
wide transition	Sends wide (new) TLVs and accepts both narrow (old) and wide (new) TLVs.	0 to 16777215

To change the IS-IS metric style of the IS-IS process, use the following command.

Set the metric style for the IS-IS process.
ROUTER ISIS mode
metric-style {narrow [transition] | transition | wide [transition]} [level-1 | level-2]
The default is narrow.
The default is Level 1 and Level 2 (level-1–2)

To view which metric types are generated and received, use the show isis protocol command in EXEC Privilege mode. The IS-IS matrixes settings are in bold.

Example of Viewing IS-IS Metric Types

DellEMC#show isis protocol
IS-IS Router: <Null Tag>
  System Id: EEEE.EEEE.EEEE IS-Type: level-1-2
  Manual area address(es):
    47.0004.004d.0001
  Routing for area address(es):
    21.2223.2425.2627.2829.3031.3233
    47.0004.004d.0001
  Interfaces supported by IS-IS:
    Vlan 2
    TenGigabitEthernet 4/22
    Loopback 0
  Redistributing:
  Distance: 115
  Generate narrow metrics: level-1-2
  Accept narrow metrics:   level-1-2
  Generate wide metrics:   none
  Accept wide metrics:     none
DellEMC#