Administrator Guide

Advertise IGP Cost as MED for Redistributed
Routes
When using multipath connectivity to an external AS, you can advertise the MED value selectively to each
peer for redistributed routes. For some peers you can set the internal/IGP cost as the MED while setting
others to a constant pre-defined metric as MED value.
The Dell Networking OS version 8.3.1.0 and later support configuring the set metric-type internal
command in a route-map to advertise the IGP cost as the MED to outbound EBGP peers when redistributing
routes. The configured set metric value overwrites the default IGP cost.
By using the redistribute command with the route-map command, you can specify whether a peer
advertises the standard MED or uses the IGP cost as the MED.
When configuring this functionality:
• If the redistribute command does not have metric configured and the BGP peer outbound route-
map does have
metric-type internal configured, BGP advertises the IGP cost as MED.
• If the redistribute command has metric configured (route-map set metric or redistribute
route-type metric) and the BGP peer outbound route-map has metric-type internal
configured, BGP advertises the metric configured in the redistribute command as MED.
• If BGP peer outbound route-map has metric configured, all other metrics are overwritten by this
configuration.
NOTE: When redistributing static, connected, or OSPF routes, there is no metric option. Simply assign
the appropriate route-map to the redistributed route.
The following table lists some examples of these rules.
Table 6. Redistributed Route Rules
Command Settings BGP Local Routing
Information Base
MED Advertised to Peer
WITH route-map metric-
type internal
MED Advertised to Peer
WITHOUT route-map
metric-type internal
redistribute isis (IGP cost
= 20)
MED: IGP cost 20 MED = 20 MED = 0
redistribute isis route-
map set metric 50
MED: IGP cost 50 MED: 50 MED: 50 MED: 50 MED: 50
redistribute isis metric
100
MED: IGP cost 100 MED: 100 MED: 100
Ignore Router-ID for Some Best-Path
Calculations
The Dell Networking OS version 8.3.1.0 and later allows you to avoid unnecessary BGP best-path transitions
between external paths under certain conditions. The bgp bestpath router-id ignore command
Border Gateway Protocol IPv4 (BGPv4) 208