Dell S4048T Configuration Manual page 213

NOTE: The bgp bestpath as-path multipath-relax command is disabled by default, preventing
BGP from load-balancing a learned route across two or more eBGP peers. To enable load-balancing
across different eBGP peers, enable the bgp bestpath as-path multipath-relax command. A
system error results if you configure the bgp bestpath as-path ignore command and the bgp
bestpath as-path multipath-relax command at the same time. Only enable one command at a
time.
The following illustration shows that the decisions BGP goes through to select the best path. The list
following the illustration details the path selection criteria.
Figure 25. BGP Best Path Selection
Best Path Selection Details
1 Prefer the path with the largest WEIGHT attribute.
2 Prefer the path with the largest LOCAL_PREF attribute.
3 Prefer the path that was locally Originated via a network command, redistribute command or
aggregate-address command.
a Routes originated with the Originated via a network or redistribute commands are
preferred over routes originated with the aggregate-address command.
4 Prefer the path with the shortest AS_PATH (unless the bgp bestpath as-path ignore command is
configured, then AS_PATH is not considered). The following criteria apply:
a An AS_SET has a path length of 1, no matter how many ASs are in the set.
Border Gateway Protocol IPv4 (BGPv4) 213