From: Héctor Fernández (gnakh@telefonica.net)
Date: Tue Aug 23 2005 - 12:57:05 GMT-3
Hi again,
It's confusing you... It's not telling you that you're forced to have the
first byte equal to 00.
Remember how an NET address is REPRESENTED for human reading:
AA.aaaa.aaaa.aaaa.aaaa.aaaa.aaaa.ssss.ssss.ssss.NN (AA and NN are 2 bytes
that are not shown together, are the rest of groups of 16 bits)
They're telling you they're going to place 3490 beginning in the second byte
instead of beginning the NSAP with 34, and that 00 is being used to fill the
AA byte.
That is: instead of using 34.9000.0100.0100.0600.00, use
00.3490.0001.0001.0006.00, that's easier to read, it belongs to area 00.3940
and has 0001.0001.0006 as system ID.
Your'e told that "as the IS-IS NET address must start and end to one octet
"<- this just refers as how it is represented... , but you've never been
forced to use 00... in fact, any NSAP address must start and end with one
octet... isn't it funny?
I'm not English and trying to express myself it's quite hard, I hope this is
clear enough.
Regards
Hictor
----- Original Message -----
From: "Stefan Grey" <examplebrain@hotmail.com>
To: <gnakh@telefonica.net>; <ccielab@groupstudy.com>
Sent: Tuesday, August 23, 2005 5:42 PM
Subject: Re: ISIS address rule question. IEWB
>
> Look on the brakedown from the IEWB workbook (this appears some times in
the
> workbook so it isn't just a mistake)
>
> Task: configure the net address as 13456
>
> brakedown,explanation:
>
> isis network entity title (NET address are in the ISO NSAP format, and are
> denoted in hexadecimal format. The above requirement states that
R1,R3,R4,R5
> and R6 be configured in IS-IS area 13456. In hexadecimal, this number
> converts to 3490. However, as the IS-IS NET address must start and end to
> one octet, and additional 00 has been added to the beginning of the
address.
>
> Could anybody comment???
>
> >From: Hictor Fernandez <gnakh@telefonica.net>
> >Reply-To: Hictor Fernandez <gnakh@telefonica.net>
> >To: "Stefan Grey" <examplebrain@hotmail.com>, <ccielab@groupstudy.com>
> >Subject: Re: ISIS address rule question.
> >Date: Tue, 23 Aug 2005 17:35:59 +0200
> >
> >Hi all,
> >
> >1st. time I've heard of that...
> >Last octet (n-selector) is what makes that NSAP address the NET, 00.
First
> >byte, 34 or 49 here, part of the area address (up to 13 bytes).
> >
> >I hope this helps
> >
> >best regards
> >Hictor
> >
> >REM: NSAP ADDRESS = AreaID (1..13 bytes), SysID (6 bytes), NSEL (1 byte),
> >and for the NSAP address to be the NET, NSEL=0x00
> >
> >----- Original Message -----
> >From: "Stefan Grey" <examplebrain@hotmail.com>
> >To: <ccielab@groupstudy.com>
> >Sent: Tuesday, August 23, 2005 4:27 PM
> >Subject: ISIS address rule question.
> >
> >
> > > There is a rule that the Net address should start and end with the
same
> > > octet. While doing different labs I can't uderstand it.
> > >
> > > 1. 3490.0001.0001.0006.00
> > > 2.490125.0001.0001.0006.00
> > >
> > > Why the first address is incorrect. And to correspond to the rule
above
> >we
> > > should use the address 00.3490.0001.0001.0006.00
> > >
> > > But the second is correct. I just can't understand it event writing
this
> > > addresses in binary.
> > >
> > > Could anybody explain?? thanks;)
> > >
> > > _________________________________________________________________
> > > Accurate weather reports for this week & the weekend!
> > > http://www.msn.ie/weather
> > >
> > >
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