routeprotocol

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…

The Administrative Distance of a Static Route by default is 1, but it adjustable from 1 to 255. Adjusting the administrative distance of a static route is a common method of providing back-up connectivity for prefixes learned by dynamic routing protocols, by specifying the administrative distance of the backup static route higher than the dynamic…

There are three main types of static routes that can be configured: Directly attached static routes Recursive static routes Fully specified static routes Directly Attached Static Routes Point-to-point serial interfaces do not need to maintain an adjacency table and do not use address resolution protocol, when used in a static route the configuration can directly…

By default on Cisco devices, routing protocols will only install the route into the routing table with the lowest metric. There is a feature within EIGRP that allows multiple routes to be installed with different metric values. This will allow for unequal cost load balancing across multiple paths. Traffic will be transmitted out over the…

When a routing protocol identifies multiple paths as a best path to a destination and the router supports multiple path entries. The router can install an additional router up a maximum number of paths per destination. This is known as equal-cost multipathing or ECMP, providing load sharing across all links. RIP, EIGRP, OSPF, and IS-IS…

Metric calculations can vary between different routing protocols. The general common concept across them is that internally learned routes are preferred than externally (such as through distribution) and the lowest metric results in a preferred route chosen.