What Routing Protocol Should Your Office Use?

There are numerous decisions to make when configuring a network, including the routing protocols that should be used. In order to make the best choice here, it’s important to understand the function of routing protocols and the difference between each type.

IP routing explained: What do protocols do?
Routing protocols are the algorithms that routers use in order to connect with one another and select paths for the transmission of data packets. In other words, routing protocols help routers identify network paths and send information between different networks.

“Routing protocols are the algorithms that routers use to select paths for the transmission of data packets.”

“Networks (LAN or WAN) on the Internet are connected to each other via routers. The movement of data from your computer to a known destination (computer) is known as routing,” Orbit Computer Solutions explained. “IP Routing is a summed up process for the set of protocols that determine the path that data follows in order to travel across different networks from its source to its destination.”

Routing protocol classifications
There are numerous routing protocols available, and they can be catalogued into different classifications. According to Cisco, classifications are chosen based on the protocol’s unique characteristics. These include:

  • Purpose protocols such as Interior or Exterior Gateway Protocol
  • Operation protocols like distance vector, link-state or patch-vector protocols
  • Behavior protocols including classless or classful – otherwise known as legacy – protocols

The most commonly-utilized protocols present in today’s networks are typically link-state routing protocols, which fall under the classless umbrella. These algorithms evolved from previously-used classless, or legacy protocols. While some networks may still have classful protocols in place, it is typically best to utilize a more current, classless protocol that will mesh with more advanced network processes.

Industry standards: OSPF and EIGRP
TechTarget contributor Cormac Long pointed out that a few of these algorithms have become industry standards, utilized in most networks. This includes the Open Shortest Path First protocol and the Enhanced Interior Gateway Routing Protocol.

The Open Shortest Path First protocol is a classless, link-state algorithm that was created in open standard format in order to enable routing across extensive, multi-vendor networks.

Long noted that there are several advantages to OSPF, including the ability to separate the network into several segments, each with a different degree of autonomy. This helps establish an organized, siloed hierarchical structure. This protocol is also known for its efficient use of IP address space. At the same time, OSPF also requires increased router memory, as each router within the network maintains a network topological database.

The Enhanced Interior Gateway Routing Protocol, on the other hand, is a hybrid classless algorithm developed by Cisco that includes characteristics of both vector and link state routing protocols. EIGRP enables the routing of several protocols and was specifically built for use within enterprise networks. This protocol also provides a load balancing option for specific types of traffic. However, because this algorithm is proprietary to Cisco, it can only function in an all-Cisco network, Orbit Computer Solutions pointed out. This means that if the network leverages any non-Cisco components, EIGRP will not function.

Additionally, eBrahma pointed out that because EIGRP does not utilize an Area-like concept for network awareness, it can be considerably inefficient when used within a large, hierarchal network.

“When running OSPF on a big network, we can make the network hierarchal by dividing the network into areas,” eBrahma stated. “Though we can separate the network into different EIGRP (AS) domain, then import routing table to each other, but it is not an optimal network design, and very few network has been designed like this.”

Protocols help each network router determine the best path for data packets to travel.

Protocols help each network router determine the best path for data packets to travel.

A brief comparison
When comparing routing protocols, it is beneficial to examine the speed of convergence, scalability, resource usage as well as the implementation and maintenance of the algorithm.

These characteristics can be leveraged to help make the best decision about routing protocols. Using OSPF and EIGRP as an example, one can see that there are several similarities, as well as one important difference between these protocols. Both algorithms have a fast speed of convergence, boast large scalability, and are more complex when it comes to implementation and maintenance.

However, they do differ in their resource usage. EIGRP utilizes a medium level of available resources, while OSPF uses a high level of resources. As noted, this is due to the fact that each OSPF router stores a topological database of the network.

At the same time, EIGRP does have drawbacks when it comes to speed of bounding queries. All Things Binary pointed out that if one router within a network using EIGRP loses its path and there is no backup in place, it must query its neighboring routers, slowing down the process. If these neighbors don’t have backups, they must query other routers, and so on, until a path is found. This can have a considerable impact on the network’s speed as one router cannot answer its neighbor’s query until its own have been answered.

When selecting a routing protocol, it is imperative to have a full understanding of the network, as well as specific needs for scalability, resource usage and speed of convergence. Utilizing this information, decision-makers and network administrators can select the protocol that will enable the best use of available resources while ensuring that data is transmitted efficiently across and outside the network.

Categories: IT Challenges, Network Reliability