Difference Between Static and Dynamic Routing

Static vs Dynamic Routing
 

Difference between static and dynamic routing is with regard to the way routing entries enter into the system. Routing in computer networking refers to the process of proper forwarding of packets across computer networks so that finally the packets reach the correct destination. Routing is of two main types as static routing and dynamic routing. In static routing, the network administrator manually sets the routing entries in the routing tables. That is where he manually putsentries that specify which path must be followed in order for a packet to reach a certain destination. On the other hand, in dynamic routing, routing entries are auto-generated using routing protocols automatically without any intervention of the network administrator. The algorithms used are complex but for current networks, which are quite large in size and ones that undergo changes often, dynamic routing is most suitable.

What is Static Routing?

In static routing, network administrator manually enters the routing entries to the routing table of each router and computer. A routing entry is an entry that specifies what the gateway that a packet must be forwarded, in order for it to reach a certain destination. On each router or computer, a table called routing table exists that contains a number of routing entries. For a simple small network, entering static routes to each router would be doable but it becomes too tedious with the increase of the size and the complexity of the network. Also, if a change occurs in a network that affects routing (for example, a router is down, or a new router is added), routing entries must be manually changed. So, in static routing, management of routing tables must also be done by the administrator. The advantage of static routing is that there is not much processing. The only action is to do a lookup on the routing table for a specific destination and hence the routing hardware must not need any sophisticated processors making them cheaper.

Difference Between Static and Dynamic Routing

A system of dynamic routing for future transportation

What is Dynamic Routing?

In dynamic routing, routing entries are auto-generated by routing algorithms. Hence, the administrator does not have to do any manual editing. Routing algorithms are complex mathematical algorithms where the routers advertize about their links and using that information, the most ideal routes are calculated. There are different methods depending on how advertising and calculations happens. Link state algorithms and distance vector algorithms are two such famous methods. OSPF ( Open Shortest Path First) is an algorithm that follows a link state algorithm and RIP (Routing Information Protocol) is an algorithm that uses distance vector algorithm. For modern large networks that involve a lot of changes during operation, dynamic routing is ideal.

In dynamic routing, routing tables are periodically updated and hence, if any change has occurred, the new routing tables would be formed according to them. Another advantage is that in dynamic routing, depending on the congestion, the routing is adapted. That is, if a certain path is too much congested, routing protocols would figure them out and those paths would be avoided in the future routing tables. The drawback of dynamic routing is that the calculation are complex that it would need considerable amount of processing. Therefore, the cost of such routing hardware would be costly.

What is the difference between Static Routing and Dynamic Routing?

• In static routing, network administrator manually enters entries to the routing tables. But in dynamic routing, network administrator does not have to enter any entries as the entries are auto generated.

• In dynamic routing, routing entries are generated using complex routing algorithms. In static routing, no such algorithms are involved.

• For static routing, the action is to just do a lookup on a table and hence does not need any processing making the hardware less costly. But, dynamic routing algorithms involves a lot of calculations. Hence, it requires much processing capabilities. As a result, the hardware would be costly.

• In static routing, routers do not advertize or broadcast any information about the links to other routers. But, in dynamic routing, tables are generated using such information advertised by routers.

• In dynamic routing, routing tables are periodically updated and hence are sensitive to any changes in the network. But, in static routing, the network administrator will have to manually do any changes.

• Static routing can be used for small networks. But, for larger networks, static routing cannot be maintained and hence dynamic routing is used.

• In static routing, if there is a link failure, communication would be affected till the link is up again or the administrator manually sets up an alternate path. But, in dynamic routing, in such an event, the routing table would be updated to have an alternate path.

• Static routing is much secure as no advertisements are sent. But, in dynamic routing, broadcasts and advertisements happens making it less secure.

Summary:

Static vs Dynamic Routing

In computer networking, routing is one of the most important things that make a computer network properly work. Static routing is the process where the administrator has to manually setup the routing entries. On the other hand, in dynamic routing, routing tables are automatically generated using algorithms called routing algorithms such as RIP and OSPF. For large complicated networks, using static routing is very tedious and hence one has to go for dynamic routing. The advantage of dynamic routing is that the routing tables will be periodically generated and hence they would comply with any change in the network. But the disadvantage is that the calculations in dynamic routing require more processing power.

 

Images Courtesy:

  1. A system of dynamic routing for future transportation by BP63Vincent (CC BY-SA 3.0)