Cisco Networking

BGP Load Sharing

What is load sharing and why to use it?Load balancing with BGP is not possible in a multihomed environment with two ISPs. BGP selects only the single best path to a destination among the BGP paths that are learned from different ASs, which makes load balancing impossible. However, load sharing Read more…

By Joe Conklin, ago
Cisco Networking

BGP Conditional Advertisement

What is conditional advertisement and why to use it?Normally, routes are propagated regardless of the existence of a different path. The BGP conditional advertisement feature uses the non-exist-map and the advertise-map keywords of the neighbor advertise-map command in order to track routes by the route prefix. If a route prefix Read more…

By Joe Conklin, ago
Cisco Networking

VRF Import/Export Maps

What are VRF import/export maps and why to use it?VRFs are an excellent tool for maintaining segregated routing topologies for separate customers or services. However, what if you needed to export only a subset of routes within a VRF? Inter-VRF routing using route targets along with BGP are the mechanisms Read more…

By Joe Conklin, ago
Cisco Networking

BGP Route Filtering

What is route filtering and why to use it?In the context of network routing, route filtering is the process by which certain routes are not considered for inclusion in the local route database, or not advertised to one's neighbours. Route filtering is particularly important for use on large networks or Read more…

By Joe Conklin, ago