Outbound traffic control is no very difficult. If you have single ISP link, icon.BGP.pngall outbound traffic will obviously exit out the link. If you have single ISP link you don’t really need BGP. If you have more than two ISP links you may have more questions. The bigges problems are redundancy and load-sharing.
Cisco_Router(config)#ip route 0.0.0.0 0.0.0.0 z.z.z.z (ISP “C” WAN IP on other side of interface)
Two ISP links on two different routers
Actually, many eCommerce user has this network layout. No simple way to make load-sharing and redundancy at the same time. However, still there is way to do it.
Still default route is needed as receiving full BGP routing table?
Yes, Tier1 ISP’s full BGP routing table would cover most of routes, but not all of them. So, we are strongly recommending configuring default route on your router or receiving default route from ISP.Single ISP link
Just put a default route or ask your ISP to provide default route thru BGP routing table.- ex) Cisco_Router(config)#ip route 0.0.0.0 0.0.0.0 x.x.x.x (WAN IP on other side of interface)
Two ISP links on same router
If you want to load-sharing outbound traffic, simply setup default route pointing to both ISP link. It will make about 50/50 traffic sharing. (It won’t exact 50/50 due to traffic is flowing per destination, but not per packet). Also, it provides redundancy as well.- ex) Cisco_Router(config)#ip route 0.0.0.0 0.0.0.0 x.x.x.x (ISP “A” WAN IP on other side of interface)
Three ISP links on same router
- ex) Cisco_Router(config)#ip route 0.0.0.0 0.0.0.0 x.x.x.x (ISP “A” WAN IP on other side of interface)
Cisco_Router(config)#ip route 0.0.0.0 0.0.0.0 z.z.z.z (ISP “C” WAN IP on other side of interface)
Two ISP links on two different routers
Actually, many eCommerce user has this network layout. No simple way to make load-sharing and redundancy at the same time. However, still there is way to do it.
