Interface delay

[canelillatunilla]

Hi guys,

Could anyone explain what interface or link delay in a router/switch is?

I think that delay has two primary factors, time for equipment to forward packets and physical distance.

The router does not know the physical distance of a link, so it can not take in account this to calculate the delay.

I think the default delay on an interface (for example, 100 us in a FastEthernet interface) is based on the time for equipment to forward frames, time since the frame has completely entered on an input interface until the frame has completely left the output interface, and this default value is constant (without considering queue load, etc.)

Am I right?

Kind regards.

[Roman Rodichev]

interface delay setting has absolutely no effect on the physical forwarding characteristics of an interface. This setting is used only by eigrp routing protocol for choosing best route

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[canelillatunilla]

I meant to say another thing, I'm not referring to the delay setting, just the delay of an interface. I'll ask almost the same question:

Could anyone explain what interface or link delay in a router/switch is?

I think that delay has two primary factors, time for equipment to forward packets and physical distance.

The router does not know the physical distance of a link, so it can not take in account this to calculate the delay.

I think the delay on an interface (for example, 100 us in a FastEthernet interface) is based on the time for equipment to forward frames, time since the frame has completely entered on an input interface until the frame has completely left the output interface.

Am I right?

Can the delay of an interface be known in advance?

Kind regards.

[Roman Rodichev]

I see what you mean. Calculating and knowing interface, line and device processing delay in advance, is pretty tricky. You might find this interesting:

http://rescomp.stanford.edu/~cheshire/rants/Latency.html