Routing

In the eleventh part of the series on computer networks, I deal with routing, i.e. routing in networks. There is a brief description, explanation of terms, and then some more common routing methods (RIP, IGRP, EIGRP and OSPF) are described very briefly, including the division of these methods. For the methods, there is a sample of the basic configuration on Cisco. The article is far from exhaustive and the description is often to the point. Finally, rooting on Windows is mentioned.

This article logically follows on from the description of VLANs. Consider that we have divided our LAN into VLANs (subnets), thereby limiting broadcast domains, segmenting the network, and gaining other benefits. But now we would need at least (or just) some VLANs to be able to communicate with each other. So we need to route between individual VLANs, this is called inter-VLAN routing. This article describes how to operate such routing and how to restrict it using an Access Control List (ACL).

This series is about routing, i.e. routing in computer networks. The individual descriptions are generally valid, but are presented here with a focus on Cisco products and with a description of configuration in Cisco IOS. This first part discusses the basic breakdown of routing protocols and category descriptions. It describes basic terms and shows general IOS configuration commands. It also covers Policy Based Routing, address summarization, filtering, and path redistribution.

The second part on routing, focusing on Cisco device configurations, covers Cisco's proprietary Enhanced Interior Gateway Routing Protocol (EIGRP).

The third part on routing, focusing on Cisco device configurations, focuses on perhaps the most widely used standardized protocol for intra-AS routing, Open Shortest Path First (OSPF).

The fourth part on routing, focusing on Cisco device configurations, discusses a competing protocol to OSPF, the standardized Intermediate System to Intermediate System (IS-IS).

The fifth installment on routing, focusing on Cisco device configurations, covers a routing protocol that is designed for routing between ASes and is used for the entire Internet, the Border Gateway Protocol (BGP).

In the previous parts of the series on routing (mainly from the perspective of Cisco elements) I briefly described the characteristics of the main routing protocols. In this latest installment, I attempt a brief tabular comparison of the main features. This is not intended for decision making when choosing a suitable routing protocol, but rather for the overview needed for the Cisco test.