HP 7102dl - ProCurve Secure Router Configuration Manual page 813

N o t e
Customer
Network 1
Figure 15-19. Load Balancing Outgoing Traffic
For example, Router A in Figure 15-19 connects to ISP 1 and ISP 2 through
two PPP interfaces. You permit PPP interface 1, which connects to ISP 1, to
receive routes for networks 1.0.0.0 /8 through 126.0.0.0 /8. PPP interface 2
receives routes for networks 128.0.0.0 /16 through 223.255.255.0 /24. The
router would learn to forward traffic to the first set of networks through PPP
interface 1 and traffic to the second set of networks through PPP interface 2.
You would configure the router as follows:
ProCurve(config)# ip prefix-list ExternalRoutes1 seq 1 permit 0.0.0.0/1 ge 8 le 8
ProCurve(config)# ip prefix-list ExternalRoutes2 seq 1 permit 128.0.0.0/1 ge 16 le 24
ProCurve(config)# router bgp 1
ProCurve(config-bgp)# neighbor 1.1.1.1
ProCurve(config-bgp-neighbor)# prefix-list ExternalRoutes1 in
ProCurve(config-bgp-neighbor)# exit
ProCurve(config-bgp)# neighbor 2.2.2.2
ProCurve(config-bgp-neighbor)# prefix-list ExternalRoutes2 in
The same general idea would hold if you were using two different routers to
connect to the two ISPs. The first router would learn the first half of the routes
and the second router would learn the second half. Because the BGP algorithm
prefers eBGP routes to iBGP routes, each router will choose the other for the
routes it did not learn. The network will send traffic destined to the first set
of addresses through the first router and traffic to the second set through the
second, effectively balancing outbound traffic.
You can also enable load sharing to enable the router to balance outbound
traffic. See "Configuring Load Sharing" on page 15-122.
IP Routing—Configuring RIP, OSPF, BGP, and PBR
Router A
Network 2
Configuring BGP
ISP 1
ISP 2
15-87