What are multi-protocol routers?

- There are routers that have the capability to route a number of protocols at the same time. 

- These routers are popularly known as the multi-protocol routers. 

- There are situations in networking where combinations of various protocols such as the appletalk, IP, IPX etc. are used. 

- In such situations normal typical router cannot help. This is where we use the multi-protocol routers. 

- Using the multi-protocol routers, information can be shared between the networks. 

- The multi-protocol router maintains an individual routing table for each of the protocols.

- The multi-protocol routers have to be used carefully since they cause an increase in the number of routing tables that are present on the network. 

- Each protocol is advertised individually by the router. 

A multiprotocol router consists of the following information:

Ø  Routing information protocol (RIP)

Ø  Boot protocol relay agent (BOOTP)

Ø  RIP for IPX

- The multi-protocol routers use this routing information protocol for performing dynamic exchange of the routing info. 

- Routers using RIP protocol can dynamically exchange information with the other routers that use the same protocol. 

- The BOOTP agent is included so that the DHCP requests can be forwarded to their respective servers residing on other subnets. 

- It is because of this, a single DHCP server can process a number of IP subnets. 

- Multi-protocol routers do not require to be manually configured.

- The networking world these days relies totally up on the internet protocol. But there are certain situations where certain tasks can be performed more efficiently by the other protocols. 

- Most of the network protocols share many similarities rather than being different. 

- Therefore, if one protocol can be routed by a protocol efficient, then it is obvious that it can route the other one also efficiently. 

- If we route the non-IP protocols in a network, this implies that the same staff that takes care of the IP monitoring is administering the non-IP routing also. 

- This reduces the need for more equipment and effort. 

- There are a number of non-IP protocols available using which a LAN can work more effectively. 

- Using a number of non-IP protocols, a network can be made very flexible and easier to meet the demands of its users. 

- All these points speak in the favor of multi-protocol routing in an abstract way. 

- But the non-IP protocols to be routed must be selected with care. 

Below we mention reasons why routing non – IP protocols can be avoided:

1. It requires additional knowledge because you cannot master everything. For individual protocol an expert is required who in case of a failure can diagnose it and fix it.
2. It puts extra load on the routers. For every protocol, the router would have to maintain a separate routing table. This calls for a dynamic routing protocol for the router itself. For all this, more memory is required along with high processing power.
3. It increases the complexity. Multi-protocol router even though it seems to be simple, it is quite a complicated thing in terms of both hardware and software. Any problem in the implementation of the protocol can have a negative impact up on the stability of all the protocols.
4. Difficulty in designing: There are separate rules for routing of each protocol, assignment of the addresses and so on. There are possibilities that there might be conflicts between these rules which means it is very difficult to design.
5. It decreases stability. Scaling capacity of certain protocols is not as good as of the others. Some of the protocols are not suited to work in a WAN environment.