Subject: Re: (ION) IPOA MIB (RFC 2320) and PVCs question

From: [email-masked]
Date: Mon, 28 Dec 98 08:20:03 EST

Michael,

>first of all thanks for your answer. Unfortenutally i still have a
>point which is unclear to me:

>>>...a different set of PVCs to other members of the LIS. In other words
>>>what i am missing is the possibility to define a set of PVCs on a per
>>>LIS basis.
>>
>>Each PVC would have a ipoaConfigPvcEntry and indexed by:
>>
>>     ipoaConfigPvcIfIndex,
>>     ipoaConfigPvcVpi,
>>     ipoaConfigPvcVci
>>
>>ipoaConfigPvcIfIndex points to the interface that the PVC is over.
>>ipoaConfigPvcVpi and Vci identify the PVC. The ifIndex via the
>>ipAddrTable should yeild local IP address.

>If i understand you right here, the connection  between a local IP
>address and a set of PVCs is the ifIndex pointing to the same (ATM)
>interface.  But this relation would be  ambigous. E.g. it would be
>able to configure different local IP addresses (from different LISs
>the client should be member of and which are also configured). The
>ifIndex of all local IP adresses could also point to the same ATM
>interface. On this ATM interface i could define a number of PVCs to
>be used with IPOA with the help of the ipoaConfigPvcTable.
>Configuring those PVCs i am not able to tell to which LIS a PVC
>"belongs". One solution i see is the use of logical interfaces (one
>for each LIS) but there is no hint in the RFC for the need of that.
>Maybe i am completly wrong with the concept and there is no need to
>tell to which LIS a PVC belongs. That would lead to all configured
>LIS being "visible" behind all configured PVCs.Which then would maybe
>also lead to some confusion in counting the ARP stuff.

RFC 2320 does discuss use of an logical interface layer, refer to the
end of section 3.0:

"The Internet Assigned Numbers Authority (IANA) ifType ipOverAtm(114)
 was created for use by systems that require a virtual IP over ATM
 interface layer.  The IF-MIB's ifStackTable SHOULD be used to show the
 relationship between virtual IP over ATM interfaces and the actual ATM
 physical interface layers."

You also state that there is no way to determine what LIS a PVC belongs
to. I'm confused about this. A LIS can be defined as an
ipoaLisEntry, some of the text in the description of this states:

  "The ipoaLisTable is indexed by ipoaLisSubnetAddr (IP
   subnet address).  An entry in the ipoaLisTable should
   exist for each ipAddrEntry that is associated with an
   ATM related interface used for Classical IP and ARP
   over ATM traffic.

   Its ipAdEntAddr and ipAdEntNetMask when ANDed together
   should equal the ipoaLisSubnetAddr of the corresponding
   ipoaLisEntry."

Each ipAddrEntry can be matched to a LIS. Each local IP address
should have an ipAddrEntry. Each PVC should have an ipoaConfigEntry
where ipoaConfigPvcIfIndex points to one or more ipAddrTable
entries. You can determine what LIS an IP Address belongs to (as
well as any related PVCs) by using the ipoaLisTable as
mentioned before.

Regards, Ken
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---

From: "Michael Fischer" <[email-masked]>
Date: Tue, 29 Dec 1998 10:12:48 +0000

Ken,

> entries. 
Ok,that  exactly was the point of my confusion. In the RFC2030 the 
description of the ipoaConfigPvcIfIndex says:
"The ifIndex of the ATM Interface that this PVC is associated with."
 I think this was misleading me quite a bit (missing the point that 
this could be a IP over ATM Virtual Intarface layer). 

Thanks a lot for your time and help,
Michael

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