IGRP Q & A

1: Which UDP port number is used to access IGRP?

*** IGRP does not use a UDP port. It is accessed directly from the network layer, as protocol number 9.

2: What is the maximum IGRP internetwork diameter, in hops?

*** The maximum IGRP network diameter is 255 hops.

3: What is the default update period for IGRP?

*** The default IGRP update period is 90 seconds.

4: Why does IGRP specify an autonomous system number?

*** IGRP specifies an autonomous system number so that multiple IGRP processes can be enabled within the same routing domain and even on the same router.

5: What is the default IGRP holddown time?

** The default IGRP holddown time is 280 seconds.

6: Which variables can IGRP use to calculate its composite metric?

** IGRP can use bandwidth, delay, load, and reliability to calculate its metric. By default, it uses only bandwidth and delay.

7: How many entries can be carried within a single IGRP update packet?

** An IGRP update packet can carry up to 104 route entries.