BGP does not perform load balancing. BGP is specifically designed to select the single best route to a destination, therefore it is not able to perform load balancing itself. However, if you can configure BGP over a virtual connection, you can get a Cisco router to balance traffic using up to six static routes.
USING EQUAL COST PATHS
To do so, you set up more than one equal cost path. Using static routes, you can easilly accomplish this. Each static route is configured to reach a matching prefix, and because they are static routes, have equal administrative distance. Most often, static routes are used between two points. BGP is then configured to run over that set of connections using the 'ebgp-multihop' command.
USING LOOPBACK INTERFACES
By setting up connections between two loopback interfaces, the routers can take advantage of the fact that the loopback interface is never down, and will be 'up' so long as it is reachable via the configured static routes.
CONFIGURING BGP 'LOAD BALANCING'
ROUTER A interface serial 0 ip address 18.104.22.168 255.255.255.252 interface serial 1 ip address 22.214.171.124 255.255.255.252 interface loopback 0 ip address 126.96.36.199 255.255.255.255 router bgp 1111 network 188.8.131.52 neighbor 184.108.40.206 version 4 neighbor 220.127.116.11 ebgp-multihop 2 neighbor 18.104.22.168 update-source loopback 0 ip route 22.214.171.124 255.255.255.255 126.96.36.199 ip route 188.8.131.52 255.255.255.255 184.108.40.206 ROUTER B interface serial 0 ip address 220.127.116.11 255.255.255.252 interface serial 1 ip address 18.104.22.168 255.255.255.252 interface loopback 0 ip address 22.214.171.124 255.255.255.255 router bgp 2222 network 126.96.36.199 neighbor 188.8.131.52 version 4 neighbor 184.108.40.206 ebgp-multihop 2 neighbor 220.127.116.11 update-source loopback 0 ip route 18.104.22.168 255.255.255.255 22.214.171.124 ip route 126.96.36.199 255.255.255.255 188.8.131.52