Passport 8xxx ipNetToMediaIfIndex

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Oct 15, 2002, 9:39:40 AM10/15/02
is there someone who can tell me how to translate the output of an
unix snmpget/snmpwalk to a ObjektID .
(ipNetToMediaIfIndex) of a nortel Passport 8600.
possible output is: 2050.ipaddress: 44632066

the same ipaddress points to interface 10 port 42 when i use the
java device manager from nortel.

how can i calculate 10/42 from 44632066

I want to write a script using snmpget commands to find
ethernet/ipaddresses on ports of our switches/routers

Juergen Schoenwaelder

Oct 18, 2002, 9:48:10 AM10/18/02

The theory is as follows. The ipNetToMediaIfIndex of the IP-MIB is
supposed to identify an entry in the ifTable which describes a
network interface. A network interface is a logical interface. If
you want to know the physical port, you can map the ifIndex of the
interface into an entPhysicalEntry of the ENTITY-MIB.

Now to the Passport 8600. First observation is that it does not support
the ENTITY-MIB. Perhaps there is something similar in a proprietary MIB
but I did not check. The good news for your problem is that the
ifName variable of the interface contains the information about the
physical port, e.g. "Slot 7, Port 5". Unfortunately, this is not what
the IF-MIB standard says you should put into this variable. But things
are getting worse. If you look at the ipNetToMediaIfIndex values, you
will find out that these values point to non-existant rows in the ifTable.
This is of course broken as it clearly violates the IP-MIB.

Conclusion: The IP-MIB/IF-MIB implementations on the Passport-8610
(3.0.3) I have looked at are broken since they do not conform to the
relevant standards. The Java GUI might know how to deal with this,
but this is of little help for you. I suggest to file a bug report
so that Nortel can fix this (perhaps they have already done so and
you just need to upgrade the firmware).


Juergen Schoenwaelder <>

Michael McNamara

Nov 27, 2002, 9:19:06 PM11/27/02
I'm happy to see that I'm not the only person trying to reverse engineer
this beast.

I did find the following link that will show you how to determine the
card/port given a reasonable IfIndex.

Did you ever get around this? If not I'll be opening a case with Nortel
next week and I'll let you know the answer.



PS: remove the NOTHANKS from the email address.

"epeter" <> wrote in message


Dec 3, 2002, 3:10:47 PM12/3/02
As promised here's the formula you'll need to use in order to get the
card/port values from the IpNetToMedia table on a Nortel Networks Passport
8600 switch.

card = (<returned integer value> AND 62914560 ) / 4194304

port = ((<returned integer value> AND 4128768) / 65536 ) + 1

I have yet to test cases where the IpNetToMedia table returns a MLT trunk. I
think it will return a card/slot of zero and then the port would be the MLT

Thanks to Shane at Nortel Networks for his help unraveling this mystery!



PS: crossposted to comp.dcom.sys.bay-networks.

"Michael McNamara" <> wrote in message

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