ADTRAN 1000R Series - Manual (Page 924)

Command Reference Guide Frame Relay Sub-Interface Config Command Set
61200510L1-35E Copyright © 2005 ADTRAN 924
spanning-tree path-cost <value>
Use the spanning tree path-cost command to assign a cost to a bridge group that is used when computing
the spanning-tree root path. To return to the default path-cost value, use the no form of this command.
Syntax Description
<value> Assigns a path cost value for spanning calculations to the bridge interface (valid
range: 0 to 65,535).
Default Values
Be default, the path-cost value is set at 19.
Applicable Platforms
This command applies to the NetVanta 1000R, 3000, 4000, and 5000 and Total Access 900 Series units.
Command History
Release 1.1 Command was introduced.
Functional Notes
The specified value is inversely proportional to the likelihood the bridge interface will be chosen as the root
path. Set the path-cost value lower to increase the chance the interface will be the root. To obtain the most
accurate spanning-tree calculations, develop a system for determining path costs for links and apply it to
all bridged interfaces.
Usage Examples
The following example assigns a path cost of 100 for bridge group 17 on a Frame Relay sub-interface:
(config)#interface frame-relay 1.16
(config-fr 1.16)#spanning-tree path-cost 100
Technology Review
Spanning-tree protocol provides a way to prevent loopback or parallel paths in bridged networks. Using the
priority values and path costs assigned to each bridging interface, the spanning-tree protocol determines
the root path and identifies whether to block or allow other paths.