Administrator Guide

Item Default
Route Flap Damping Parameters
half-life = 15 minutes
reuse = 750
suppress = 2000
max-suppress-time = 60 minutes
Distance
external distance = 20
internal distance = 200
local distance = 200
Timers
keepalive = 60 seconds
holdtime = 180 seconds
Add-path Disabled
Implement BGP with Dell EMC Networking OS
The following sections describe how to implement BGP on Dell EMC Networking OS.
Additional Path (Add-Path) Support
The add-path feature reduces convergence times by advertising multiple paths to its peers for the same address prex without replacing
existing paths with new ones. By default, a BGP speaker advertises only the best path to its peers for a given address prex. If the best
path becomes unavailable, the BGP speaker withdraws its path from its local RIB and recalculates a new best path. This situation requires
both IGP and BGP convergence and can be a lengthy process. BGP add-path also helps switchover to the next new best path when the
current best path is unavailable.
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-dened metric as MED value.
Use 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 congured 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 conguring this functionality:
• If the redistribute command does not have metric congured and the BGP peer outbound route-map does have metric-
type internal congured, BGP advertises the IGP cost as MED.
• If the redistribute command has metric congured (route-map set metric or redistribute route-type
metric) and the BGP peer outbound route-map has metric-type internal congured, BGP advertises the metric congured
in the
redistribute command as MED.
• If BGP peer outbound route-map has metric congured, all other metrics are overwritten by this conguration.
NOTE
: When redistributing static, connected, or OSPF routes, there is no metric option. Simply assign the appropriate route-
map to the redistributed route.
184 Border Gateway Protocol (BGP)