ingress, egress, inbound, outbound....

Answered Question
Mar 24th, 2009

I am so confused among these terms. Could anyone please clarify them for me from the switching point of view? I am learning QoS and seems that switch has ingress as well as an egress buffer/queues. Does each interface have its own ingress and egress queues? When a frame comes into the switch, will the switch puts it into the ingress queue of the receiving interface or will switch it first then put it into the ingress queue of the outgoing interface?? Thanks!

I have this problem too.
0 votes
Correct Answer by scottmac about 7 years 8 months ago

You are basically correct.

There's a little more going on in the device between ingress and egress. QOS is part of it, port contention is part of it, administrative process (things like managing the CAM, TCAM, ACLs & such) are another part of it.

I haven't seen anything from Cisco lately, it used to be part of the classroom training for switches & routers, but I'm not sure they include it there anymore either.

But, again, you're basically correct ... (ingress==>{switching/routing stuff}==>egress) and depending on what kind of QOS, some stuff changes on the {switching/routing stuff} and/or the ingress and/or the egress queues.

Good Luck

Scott

  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 4.5 (2 ratings)
Loading.
scottmac Tue, 03/24/2009 - 17:12

It is all from the perspective of the device being discussed.

Inbound, ingress = traffic coming to the device or interface

Outbound, egress = traffic leaving the device

The terms are usually applied from outside the device ... such that ingress traffic doesn't become egress traffic until it physically leaves / is transmitted from the device.

Anything happening inside the device isn't usually talked about as ingress or egress from some specific internal process or component.

Good Luck

Scott

Difan Zhao Wed, 03/25/2009 - 09:36

Hi Scott, Thanks for reply! So there is no difference between ingress and inbound then? So for example if a frame comes in FE1/0/1 and leaves at FE1/0/2, will the frame be stored in the ingress queue of the FE1/0/1 and then gets switched to the egress queue of FE1/0/2 waiting to be transmitted? Does Cisco have a diagram explaining these switch processes from receiving the frame, switching it and where QoS kicks in and process the frame? Thanks!

Correct Answer
scottmac Wed, 03/25/2009 - 11:56

You are basically correct.

There's a little more going on in the device between ingress and egress. QOS is part of it, port contention is part of it, administrative process (things like managing the CAM, TCAM, ACLs & such) are another part of it.

I haven't seen anything from Cisco lately, it used to be part of the classroom training for switches & routers, but I'm not sure they include it there anymore either.

But, again, you're basically correct ... (ingress==>{switching/routing stuff}==>egress) and depending on what kind of QOS, some stuff changes on the {switching/routing stuff} and/or the ingress and/or the egress queues.

Good Luck

Scott

vikyahmad11 Wed, 06/01/2016 - 22:09

ingress=login,...     traffic coming from outside to inside router....

Egress=exit.......  traffic going out from inside side to out side

Actions

This Discussion