igrp confusion.

[tushar47]

Dear sir,

I want to know how the triggered updates work in IGRP routing protocol. Means what is the significance of triggered updates in IGRP?

Regards,

Tushar.

[Josef Oduwo]

An IGRP triggered update is a new routing table that is sent immediately, in response to some change. The most important change is removal of a route. This can happen because a timeout has expired (probably a neighboring gateway or line has gone down), or because an update message from the next gateway in the path shows that the path is no longer usable.

For example when a gateway detects that a route is no longer usable, it triggers an update immediately. This update will show that route as unusable.

Otherwise here is an intro to IGRP, http://www.cisco.com/en/US/tech/tk365/technologies_white_paper09186a00800c8ae1.shtml#updateproc

Josef.

[sushilk]

Hi Tushar,

Several features are introduced to provide stability in situations where the topology is changing one of which is TRIGGERED UPDATES.

IGRP uses the triggered updates to speed up the convergence time. Any network change like link comming up or going down can trigger an update thet will be sent to each router. So instead of waiting for the update timer to expire you can speed up the network convergence by using triggered updates.

Following link will give you a better understanding on triggered updates and other features & functionality of IGRP:

http://www.cisco.com/en/US/tech/tk365/technologies_white_paper09186a00800c8ae1.shtml#updateproc

Regards