Subject: RE: [Isis-wg] contents of the MIB object: isisManAreaAddr

From: Jeff Parker <[email-masked]>
Date: Fri, 7 Jan 2000 12:30:23 -0500

> > To be honest, [isisSysMaxAreaAddresses] is 3.  
> > It is 3 in all existing implementations, and it is 
> > a show stopper if two implementations don't agree.   
> > 
...
>   Just for the record, in IOS, since about a year, you can configure
>  isisSysMaxAreaAddresses 3..254. You're lucky, IOS does not implement
>  an ISIS MIB (yet). But I implemented it because of pressure that
>  some ADM vendors "could do isisSysMaxAreaAddresses up to 8". Also
>  note that  ADMs usually only implement CLNS routing, not IP routing.
>  For CLNS routing multiple isisSysMaxAreaAddresses is a little more 
>  usefull. Still bad network design, IMHO. Oh, and I don't think any
>  of our customers use it. ;-)
> 
>      Henk.

I think Henk has just demonstrated the importance of keeping 
such conversations on the list.  Thanks, Henk!

- jeff

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From: Matthew Kontoff <[email-masked]>
Date: Fri, 07 Jan 2000 13:47:26 -0500

> >  of our customers use it. ;-)

The Avici TSR supports 1..255 area addresses.

Matt

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From: "Rajesh Saluja" <[email-masked]>
Date: Fri, 07 Jan 2000 14:02:09 -0500

Why can't this be 0 ? Do you need at least one manual area address for
L2-only router also?  To me, it seems that
isisSysMaxAreaAddresses can be 0..X.

Thanks,
Rajesh

--

-------------------------------------------------------------
Rajesh Saluja
Nortel Networks Inc 600 Technology Park Billerica, MA  01821
Ph: (978) 288-7791      Fax: (978) 670-8760
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From: Jeff Learman <[email-masked]>
Date: Fri, 07 Jan 2000 16:39:49 -0500

Rajesh,

Some implementations may permit it to be provisioned to zero,
but only because 0 in the PDU actually means "use the standard
default of 3".

At least one area address is absolutely required to do any
CLNP routing at all, which is what IS-IS was originally designed
for.  A level 2 router is, according to the IS-IS spec "also a
level 1 router in its own area", although there may be some
implementations that skirt this issue.

Practically speaking, though, there isn't any advantage to setting
the value below three -- since it has to be the same for all ISs
in the area, it's a bad idea to change it from the default of 3
unless you really need to (or *feel* you need to).

Jeff

>> The Avici TSR supports 1..255 area addresses.
____________________________________________________________________

  Jeff Learman                           Internet:     [email-masked]
  Engineering Manager                    Voice:     (734)-975-7323
  ONE (Open Networks Engineering, Inc)   Fax:       (734)-975-6940
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