Concept Guide

By default, the system 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.
The system supports the following IS-IS metric styles.
Table 43. 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
Dell#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
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
Dell#
Configuring the IS-IS Cost
When you change from one IS-IS metric style to another, the IS-IS metric value could be affected. For each interface with IS-IS
enabled, you can assign a cost or metric that is used in the link state calculation.
To change the metric or cost of the interface, use the following commands.
● Assign an IS-IS metric.
INTERFACE mode
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Intermediate System to Intermediate System