Reference Guide

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. FTOS supports five
different metric styles: narrow, wide, transition, narrow transition, and wide transition.
By default, FTOS 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.
FTOS supports the following IS-IS metric styles.
Table 15. Metric Styles
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
FTOS#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
GigabitEthernet 4/22
355