Contents of this article
In this article I describe the Diffusing Update Algorithm DUAL for EIGRP. EIGRP do not use UDP or TCP protocols to send the update packets on a network. Routing protocols helps router to build and maintain the routing table in routers. Routing protocols are one important part of default routing in router. Routing protocols inform the router about the networks connected at each interface. Routing protocols doesn’t carry or push the data packets in any way. Any change in the network required to be update in the routing tables of all routers. This task is carried out by the routing protocols. Routing protocols help the routers to select the best path to exit the data packets.
Example of routing protocols are RIP, RIPv2, IGRP,OSPF etc. Routing protocols further divided into distance vector, link state and hybrid protocols. These all routing protocols update the routing table of all routers in the network. You can see the routing protocols by “show ip route” command in privilege command mode of router. Routing protocols are not responsible for data packet flow in any way. Routing protocols spread the information of network hierarchy to all routers.
Diffusing Update Algorithm DUAL for EIGRP
Diffusing Update Algorithm DUAL decide the best path for the data transmission for EIGRP. The main function of Diffusing Update Algorithm is to prevent routing loops when the router working on EIGRP protocol. Diffusing Update Algorithm is a convergence mechanism system that is created to be used by the EIGRP protocol only. The DUAL function on many scenarios by calculation of multiple terms used by EIGRP. The full name of Diffusing Update Algorithm DUAL is DUAL finite state machine. DUAL works when the main path selected by EIGRP is went down or it is required to select another path. The DUAL algorithm help to select the best alternative path for router.
DUAL works when the existing network topology changed or any existing device goes down. Topology table and neighbour routing table refers by Diffusing Update Algorithm DUAL immediately to select the best path by the EIGRP to send the data to its destination. The path selection done with one thing taken to avoid and that is loop free routes. In other words we can say when no feasible route are available the DUAL algorithm immediately come in action and start computing the best alternative route.
Working of Diffusing Update Algorithm DUAL for EIGRP
There are three different tables used by Diffusing Update Algorithm DUAL for calculation of best route. These table names are neighbour routing table, topology table and own routing table. All three tables maintained by the EIGRP information exchange between the neighbour routers.
The neighbour table keep the information of all directly connected routers. Each table keep the information of network interfaces and address of neighbour routers. A hello packets sent and received to check the status of neighbour router. The reply of hello packet decided whether the neighbour router is in working condition or not. If the reply of hello packet not received in a predefined time the router assume to be dead.
The next is topology table which keep the information of metrics of all routes in the network. This information collected by the neighbour routers. The successor and feasible successor keep the best path and alternative path information. So in case of failure of successor the feasible successor selected with some other terms like reported distance and feasible distance. DUAL calculate the best alternative path on the basis of above terms.
Conclusion on Diffusing Update Algorithm DUAL for EIGRP
DUAL algorithm make the EIGRP converge easy and fast. The basic thing maintained by EIGRP is the routing table updates from neighbours router. This copy of routing table help for calculate the cost of path to a remote destination network. So now the router is known the best path for the data sent to remote destination network. Now suppose the best path goes down then the router immediately check the topology table for feasible successor.
The second thing is router approach to the neighbour router to give update routing table. Then the neighbour router suggest the best path to router. By using above both scenario the router will select the best path for the remote network. The whole process is done by a DUAL strategy. So that’s how the Diffusing Update Algorithm DUAL work for EIGRP.
I hope you found this article helpful to understand the Diffusing Update Algorithm DUAL for EIGRP. For any query or suggestion you may drop a comment below or contact us. Your suggestions are always welcome by us.
