Install Guide

deny 703:667
deny 704:666
deny 705:666
deny 14551:666
DellEMC#
Configure BGP attributes
Following sections explain how to configure the BGP attributes such as MED, COMMUNITY, WEIGHT, and
LOCAL_PREFERENCE.
Changing MED Attributes
By default, Dell EMC Networking OS uses the MULTI_EXIT_DISC or MED attribute when comparing EBGP paths received from
different BGP neighbors or peers from the same AS for the same route. You can configure the device to compare the MED
attributes from neighbors or peers in different AS using the bgp always-compare-med command.
To change the usage of MED attribute to choose the best path among the advertised, enter any or all of the following
commands.
● Enable MED comparison in the paths from neighbors with different ASs.
CONFIG-ROUTER-BGP mode
bgp always-compare-med
By default, this comparison is not performed.
● Change the bestpath MED selection.
CONFIG-ROUTER-BGP mode
bgp bestpath med {confed | missing-as-best}
○ confed: Chooses the bestpath MED comparison of paths learned from BGP confederations.
○ missing-as-best: Treats a path without a MED value as the most preferred one.
To view the non-default values, use the show config command in CONFIGURATION ROUTER BGP mode.
Manipulating the COMMUNITY Attribute
A COMMUNITY attribute indicates that all the routes with that attribute belong to the same community grouping. In addition to
permitting or denying routes based on the values of the COMMUNITY attributes, you can manipulate the COMMUNITY attribute
value and send the COMMUNITY attribute with the route information.
By default, Dell EMC Networking OS does not send the COMMUNITY attribute to a BGP neighbor or a peer group.
To send the COMMUNITY attribute to BGP neighbors, use the following command.
● Enable the software to send the router’s COMMUNITY attribute to the BGP neighbor or peer group specified.
CONFIG-ROUTER-BGP mode
neighbor {ip-address | ipv6-address | peer-group-name} send-community [extended |
standard]
extended- Allows to send the extended community attribute to a BGP neighbor or peer group.
standard- Allows to send the standard community attribute to a BGP neighbor or peer group.
To view the BGP configuration, use the show config command in CONFIGURATION ROUTER BGP mode.
If you want to remove or add a specific COMMUNITY number from a BGP path, you must create a route map with one or both
of the following statements in the route map. Then apply that route map to a BGP neighbor or peer group.
1. Enter ROUTE-MAP mode and assign a name to a route map.
CONFIGURATION mode
route-map map-name [permit | deny] [sequence-number]
2. Configure a set filter to delete all COMMUNITY numbers in the IP community list.
178
Border Gateway Protocol (BGP)