Order of router operation

Answered Question
Jul 12th, 2007
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Hi Friends,

I would like to know what is the order in which the router processes a packet. For eg. when a router receives a packet, it would check the routing table, ACL, QOS, NAT etc ... What is the order in which these operations are carried out. The one that i found from cisco website seems to be specific to only NAT & QoS operations but I would like to know in general. Thanks in advance for your assistance.



Correct Answer by Amit Singh about 10 years 1 week ago

Hi Manoj,

This link should help.


HTH,Please rate if it does.

-amit singh

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Overall Rating: 5 (2 ratings)
Manoj Wadhwa Sat, 07/14/2007 - 19:28
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Hi Amit,

The link that you provided only mentions NAT order of operation. But in general, if there is NAT, QOS, ACL's etc configured, which one takes precedene first and how the order of operations goes on. This is what i am looking for. Thanks!



royalblues Sun, 07/15/2007 - 02:20
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The link actually tells all the operations that a router performs when a packet enters it and not just when NAT is configured.

As per the document ACL will be the 3rd in order whether nat is configured or not.

If NAT is configured then that action would be taken only after all the above actions are already taken by the router



Manoj Wadhwa Mon, 07/16/2007 - 06:20
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Hi Amit/ Narayan,

I was a bit lethargic to go through the complete document. I have found the info. in the page now. Thx for your help guys.




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