Configuring Med For As; Comparing The Med Routing Metrics From The Peers In Different Ass - Huawei Quidway S3500 Series Operation Manual

Operation Manual - Routing Protocol
Quidway S3500 Series Ethernet Switches
Table 5-29 Configuring the local preference
Configure the local preference
Restore the default local preference
The local preference is transmitted only when the IBGP peers exchange the update
packets and it will not be transmitted beyond the local AS.
By default, the local preference is 100.

5.2.12 Configuring MED for AS

Multi-Exit Discriminators (MED) attribute is the external metric for a route. It is
exchanged between ASs. However, it will not be transmitted beyond an AS once it is
imported into the AS.
AS uses the local preference to select the route to the outside and MED to determine
the optimum route for entering the AS. When a router running BGP gets routes with the
same destination address but different next hops through different external peers, it will
select the route of the smallest MED as the optimum route, provided that all the other
conditions are the same.
Perform the following configurations in BGP view.
Table 5-30 Configuring an MED metric for the system
Configure an MED metric for the system
Restore the default MED metric of the system
The router configured above only compares the route MED metrics of different EBGP
peers in the same AS. Using the compare-different-as-med command, you can
compare the route MED metrics of the peers in different ASs.
By default, MED metric is 0.

5.2.13 Comparing the MED Routing Metrics from the Peers in Different ASs

It is used to select the best route. The route with smaller MED value will be selected.
Perform the following configurations in BGP view.
Operation
Operation
Huawei Technologies Proprietary
5-17
Chapter 5 BGP Configuration
Command
default local-preference value
undo default local-preference
Command
default med med-value
undo default med