NSEL

rohitraizaday · ‎09-25-2007

Hi,

In ISIS address if NSEL value is 01 , what it signify ?

nambi_gct · ‎09-26-2007

Hi,

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).

http://www.cisco.com/en/US/tech/tk365/technologies_white_paper09186a00800a3e6f.shtml#wp38674

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

Thanks

Nambi

rohitraizaday · ‎09-26-2007

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.

Regards,

Rohit

nambi_gct · ‎09-26-2007

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.