Changing Med Attributes; Changing The Local_Preference Attribute - Dell S4820T Configuration Manual

Changing MED Attributes

By default, Dell Networking OS uses the MULTI_EXIT_DISC or MED attribute when comparing EBGP
paths from the same AS.
To change how the MED attribute is used, 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: Treat a path missing an MED as the most preferred one.
To view the nondefault values, use the show config command in CONFIGURATION ROUTER BGP
mode.

Changing the LOCAL_PREFERENCE Attribute

In Dell Networking OS, you can change the value of the LOCAL_PREFERENCE attribute.
To change the default values of this attribute for all routes received by the router, use the following
command.
• Change the LOCAL_PREF value.
CONFIG-ROUTER-BGP mode
bgp default local-preference value
– value: the range is from 0 to 4294967295.
The default is 100.
To view the BGP configuration, use the show config command in CONFIGURATION ROUTER BGP
mode or the show running-config bgp command in EXEC Privilege mode.
A more flexible method for manipulating the LOCAL_PREF attribute value is to use a route map.
1. Enter the ROUTE-MAP mode and assign a name to a route map.
CONFIGURATION mode
route-map map-name [permit | deny] [sequence-number]
2. Change LOCAL_PREF value for routes meeting the criteria of this route map.
CONFIG-ROUTE-MAP mode
set local-preference value
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Border Gateway Protocol IPv4 (BGPv4)