Routing

Equal Cost Load Balancing EIGRP permits multiple successor routes with an equal metric to be installed into the routing table for load balancing. Installing multiple routes for the same prefix is known as equal cost multipathing, or ECMP. Unequal Cost Load Balancing EIGRP also supports unequal-cost load balancing, which permits the installation of the successor…

Before EIGRP IGRP uses multiple factors to calculate the metric for a path. Metric calculation uses bandwidth and delay by default, but can include load and reliability too. Metric = (K1 * Bandwidth + ( (K2 * Bandwidth) / (256 – Load) ) + K3 * Delay) * ( K5 / (K4 + Reliability) IGRP…

When an adjacency is formed, neighbouring EIGRP routers exchange their entire routing table, following exchanges only contain partial updates as the topology changes in the network. EIGRP uses five different types of packets to communicate with other routers, with it’s own IP number – 88. Type Packet Name Function 1 Hello Discovering EIGRP neighbour and…

In EIGRP there is a topology table that is separate from the routing table. This topology table makes EIGRP different from a traditional distance vector protocol and contains information to identify loop-free routes. Each entry in this topology table contains: The network prefix EIGRP neighbors that have advertised that network prefix The metrics from each…

Term Definition Feasible Successor A route that satisfies a feasibility condition and is kept as a backup route. The condition is that the backup route is loop free. Feasibility Condition The condition that for a route to be considered a backup route, the reported distance received must be less than the feasible distance calculated locally.…

A router can run multiple EIGRP processes. Each process operates under a unique number known as a Autonomous System, or AS number. In EIGRP, only routers with the same AS number can exchange routes with each other and form neighbour relationships. If a router operates multiple EIGRP processes, a router will not transmit routes learned…

Enhanced Interior Gateway Routing Protocol (EIGRP) is a distance vector protocol often used in Cisco networks. For many years it was a Cisco proprietary protocol, but was released to the Internet Engineering Task Force with RFC 7868 and ratified in May 2016. EIGRP has some advantages over lesser distance vector protocols such as RIP, such…

Virtual Routing and Forwarding is a technology which creates a separate virtual router inside of a physical router. The virtual routers interfaces, routing and forwarding tables are completely isolated from the physical router and other virtual routers, preventing traffic from traversing from one virtual router to the other. By default, all interfaces belong to the…

IPv6 static routes are configured with the following command: ipv6 route 2001:ff8:33::/64 GigabitEthernet0/0 2001:bb8:3::3 Ensure that IPv6 routing is enabled on the Cisco router with the command ipv6 unicast-routing The IPv6 routing table can be viewed with the command show ipv6 route

The null interface is a non-physical interface that is always in an up state. Any traffic that is sent to the virtual null interface is dropped without any additional overheads added to the CPU. Configuring a static route towards a null interface provides a method of dropping network traffic without the need of an access…