Routing can be classified into three major types namely static routing, dynamic routing and the combined static and dynamic routing. In this article we center our discussion up on these 3 routing types.
What is Static Route?
– A route that is configured manually by the router is termed as the static route.
– It is also the route that a network administrator creates manually.
– The information concerning the networks that have a direct connection with the active router interfaces is initially mentioned in the router table.
– Such direct routes are specifically called as the connected routes.
– Configuring the routes manually is one way in which the router can learn about the roots.
– Static routing is sometimes also referred to as the non – adaptive routing.
– However, manual configuration is only possible for networks that are smaller in size.
– For the larger networks manual configuration does not work.
What is a Dynamic Route?
– The second type of routes or the dynamic routes are the ones that are learnt by the router via the routing protocols.
But here how routing protocols actually learn?
– They learn from the other routers that lie in the neighborhood operating up on the same routing protocol.
– Network numbers and how to reach a particular network as known by a router are shared by the dynamic routing protocols.
– Through such a sharing process, a router is capable of learning about all the reachable network numbers.
– By both types of routing, a routing table is maintained by the host systems and the routers.
– The tables are updated by the routing daemon on each system regarding all the known network routes.
– It is the role of the kernel to read the contents of the routing table and direct the packet forwarding in to the local network.
– The IP addresses of the networks known by the system are listed in the routing table that is inclusive of the default/ local network address.
– The IP address corresponding to every known network’s gateway system is also listed by the routing table.
– A gateway system is the one that has been designed for receiving the outgoing packets and again forwarding them one step beyond the default/ local network.
On what systems static and dynamic routing are configured?
– On a Solaris system, option is available for configuring both types of routing i.e., static and dynamic.
– On a single system only either one or both types of routing can be configured.
– If dynamic routing is in play the system will use the routing protocols for the maintenance of its routing tables.
– Some examples of such routing protocols are:
1. RIPng for IPv6 networks and
2. RIP for IPv4 networks
– On the other hand, the system following the static routing will not use any of these protocols for updating the routing tables and routing the info.
Then here what is to be done?
– The network routes known to the system must be maintained manually using the command called ‘route’.
– Therefore, complex topologies that have a rapid changing nature are used for the construction of the routing tables.
– But this process is even more complex.
– One type of network called the PSTN (public switched telephone network) relies on the pre – computed routing tables. – These routing tables have fallback routes which offer the advantage if the direct routes are experiencing a blockage.
– During the configuration of the routing for autonomous system, type of the routing to be supported by the hosts and routers must be considered.
– Hosts obtain their routes from a default folder in static routing.
– Default routers only need to have information about maximum 2 routers available on the next few hops.
Combined Static and Dynamic Routing
– There is a third kind of routing that is commonly used and it is called the combined static and dynamic testing.
– This type is used by two types of routers:
1. Routers connecting the dynamically routed network and a statically routed network.
2. Border routers connecting the external networks and the interior autonomous systems.
– It is quite a common practice to combine and use the static and dynamic routing.