Interface delay

luke_bibby

Pretty easy question i guess but I'm just reviewing some stuff before i take my ICND2 exam, and am wondering exactly what the interface delay is (as defined in the EIGRP metric calculation)? Is is the time delay between transmitting packets?

kalebksp

I believe delay is supposedly the delay a packet experiences between being sent out the interface and reaching it's next hop. It's a static value that is assigned on the interface with the "delay" command.

tech-airman

luke_bibby wrote: »

Pretty easy question i guess but I'm just reviewing some stuff before i take my ICND2 exam, and am wondering exactly what the interface delay is (as defined in the EIGRP metric calculation)? Is is the time delay between transmitting packets?

luke_bibby,

Assume the following network:

[PC1]---(R1)---(R2)---(R3)---[PC2]

Let's say PC1 is in the subnet 192.168.1.0/24. The link between (R1) and (R2) is in the subnet 192.168.2.0/24. The link between (R2) and (R3) is in the subnet 192.168.3.0/24. The PC2 is in the subnet 192.168.4.0/24. Let's say the link between (R1) and (R2) takes 100.5 microseconds. Let's say the link between (R2) and (R3) takes 100.5 microseconds. So, from the perspective of (R1), the delay to reach the subnet that PC2 is in, the subnetwork 192.168.4.0/24, it takes 100.5 microseconds + 100.5 microseconds = 201.0 microseconds. However, since binary doesn't understand the concept of decimal points, the value is multiplied by 10 so 201.0 microseconds -> 2010 delay value. So the delay value is the CUMULATIVE delay FROM the remote sub/network TO the local router. Does this make sense?

Source:

1. "IP Routing - Enhanced Interior Gateway Routing Protocol" webpage @ cisco.com - Enhanced Interior Gateway Routing Protocol - Cisco Systems