Concept Guide
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DellEMC#
Congure BGP attributes
Following sections explain how to congure 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 dierent
BGP neighbors or peers from the same AS for the same route. You can congure the device to compare the MED attributes from
neighbors or peers in dierent 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 dierent 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 specied.
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 conguration, use the show config command in CONFIGURATION ROUTER BGP mode.
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Border Gateway Protocol (BGP)