Lwapp Mailing List: Re: Another Way to Think about CAPWAP

[s. goswami (sgoswami]

James, see my comments inline.

On Thu, 13 Nov 2003, James Kempf wrote:

> So here's a possible other way to think about CAPWAP, inspired by talking
> with Bernard Abboba, that may point a way out of the "to SNMP or not to
> SNMP" discussion.
>
> Here at IETF 58, the NOC apparently has provisoned with "too many" access
> points, and partially as a result, the access points keep appearing and
> disappearing as the load changes and they interfere with each other,
> according to some conversation we were having last night.
>

Are you assuming these Access Points to be Access Routers also ? The
AP's are L2 devices whereas AR's are L3 devices. Not all AP's are
AR's.

> This behavior is kind of like route flapping, and, when you think about it,
> CAPWAP is acting kind of like a routing protocol. That is, it is
> communicating between access points for purposes of power and load control,
> among others. The difference is that the CAPWAP Access Controller (or AR) is
> co-ordinating the control, rather than having distributed control as in
> routing protocols. I believe this difference is primarily because the access
> network topology is almost exclusively a star with respect to the
> controlling switch or router, rather than a mesh as in general IP networks.
> That is, it is never the case that an access point functions as a forwarding
> intermediary (note that this would not be the case in a mesh or multihop
> network, but CAPWAP isn't intended for those kinds of networks).
>

Would CAPWAP handle a mixed environment of pure L2 AP and L3 AR ?

> Now, nobody would suggest using SNMP for routing information distribution,
> though I suppose it could be used for that purpose. So, while SNMP may have
> value for managing the static configuration of access points, it isn't the
> appropriate protocol for managing the routing.
>

I do not agree with your opinion of SNMP (it would be beneficial if you
could list a few problems in using SNMP). SNMP SMI has the appropriate
Information Model to manage routing. The SNMP transport protocol may
not be appropriate for carrying routing information in a "mesh"
network.

Subrata

> Sound reasonable?
>
>             jak
>
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