Cisco Networking

BGP Load Sharing

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 is possible in such multihomed BGP networks. To Read more…

By Joe Conklin, ago
Cisco Firewall

Configuring Dynamic Multipoint VPN and Zone Based Firewall

DMVPN provides the capability for creating a dynamic-mesh VPN network without having to pre-configure (static) all possible tunnel end-point peers, including IPsec (Internet Protocol Security) and ISAKMP (Internet Security Association and Key Management Protocol) peers. DMVPN is initially configured to build out a hub-and-spoke network by statically configuring the hubs Read more…

By Joe Conklin, ago
Cisco Networking

Configuring Layer 3 MPLS VPN over GRE

The MPLS VPN L3VPN over GRE feature provides a mechanism for tunneling Multiprotocol Label Switching (MPLS) packets over non-MPLS networks. This feature allows you to create a generic routing encapsulation (GRE) tunnel across a non-MPLS network. The MPLS packets are encapsulated within the GRE tunnel packets, and the encapsulated packets Read more…

By Joe Conklin, ago
Cisco Networking

BGP Conditional Advertisement

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 is not present in output of the non-exist-map Read more…

By Joe Conklin, ago
Cisco Networking

VRF Import/Export Maps

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 to facilitate this.¬†This kind of design is generally seen Read more…

By Joe Conklin, ago
Cisco Networking

BGP Route Filtering

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 on the Internet where it is used for Read more…

By Joe Conklin, ago