nambi_gct Wed, 09/26/2007 - 05:56


Where did you see this value.In IS-IS an NET is defined as NSAP with NSEL set to 0.NSEL is like TCP port number and indicates the transport layer.All router NETs have an n-selector of zero, implying the network layer of the IS itself (0 means no transport layer).

Hence you would not see NSEL as 01 in ISIS.This is my understanding.



rohitraizaday Wed, 09/26/2007 - 07:56

Hi Nambi,

You are right, even i find the same thing in books, but in one presentation related with DCN network i find NSEL value is 01.



nambi_gct Wed, 09/26/2007 - 18:33

Hi Rohit,

Did you see an ISIS router using a NET with 01 NSEL.ISIS does not have any dependency on transport layer.NSEL can have values other than 0 for any application that runs on OSI stack implementations.What you saw may be an upper layer application.


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