Command Reference Guide

3Com Router 5000 Family and Router 6000 Family apply tag ● 19
Command Reference
apply tag
Purpose Use the apply tag command to set the tag area of OSPF route information.
Use the undo apply tag command to cancel the apply clause.
Syntax apply tag value
undo apply tag
Parameters value
Specifies the tag value of route information.
Example Display how to define one apply clause. When it is used for setting route information
attribute, it sets the tag area of route information as 100.
[3Com -route-policy] apply tag 100
View This command can be used in the following views:
■ Routing Policy view
Description When a route is redistributed from protocol A to protocol B, and is redistributed back
to protocol A on some other routers, protocol A allows the tag field of the routing
protocol update packet to be transferred to the peer, that is, the information in the
tag field can traverse from protocol A to protocol B and then back to protocol A,
without being lost.
OSPF, RIP2, ISIS, and BGP support the tag field, but RIP1 does not.
For example, when a BGP route is redistributed into OSPF and then redistributed back
to BGP on another router, the as-path attribute of the BGP route is lost. You can the
aplly tag command to set the OSPF tag field as as-path to guarantee the integrity
of the as-path attribute.