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…
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…
Layer 2 VPNs are a type of Virtual Private Network (VPN) that uses MPLS labels to transport data. The communication occurs between routers that are known as Provider Edge routers (PEs), as they sit on the edge of the provider's network, next to the customer's network. Internet providers who have Read more…
A virtual private network (VPN) extends a private network across a public network, and enables users to send and receive data as if their computers were directly connected to the private network. A site-to-site VPN allows offices in multiple fixed locations to establish secure connections with each other over a Read more…
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…
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…
Inter-vlan routing is defined as a process of forwarding network traffic from one vlan to another vlan using a router or layer 3 device. To facilitate inter-vlan routing a router must be connected to the switching infrastructure or the switch must support layer 3 routing locally. For each vlans to Read more…
Load balancing is a standard functionality of the Cisco IOS router software, and is available across all router platforms. It is inherent to the forwarding process in the router and is automatically activated if the routing table has multiple paths to a destination. It is based on standard routing protocols, Read more…
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…
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…