Re: [IPFIX] Comments on draft-kashima-ipfix-data-link-layer-monitoring-01.txt

[Paul Aitken <[e-mail]>]

Nevil,

> This draft introuces three new IPFIX Information Elements (IEs)
> that would enable IPFIX to be used for monitoring (parts of) in
> data-link-layer parts of packet headers.  It concentrates on Ethernet,
> especially as used in providing layer-2 VPN services (IEEE 802.1ad
> and 802.1ah).
> 
> Now that I've read it and thought about it, I have three comments:
> 
> 1. The IPFIX/PSAMP architecture standardises the collection of
>    *IP-related* data, this proposal would extend it to cover data from
>    other parts of a packet's headers.  That would be a significant
>    extension.  Is there support for such a generalisation?

Yes, very much so. We have customer need for this. It would be far 
preferable for us to standardise through IPFIX than to go down a 
proprietary route.

Note that there is precedent for this, since the IPFIX info model 
already contains some non-IP fields - eg, MPLS, MAC address, VLAN.


> 2. It's presented as a simple, minimal extension to IPFIX/PSAMP,
>    simply adding three new IEs PSAMP IEs, i.e with numbers above 338.
>    Does it provide enough detail?

Actually, the dataLinkFrameSize and dataLinkFrameSection definitions are 
simply verbatim copies from the old draft-ietf-psamp-info-09.


>    Should there be more than just three?
>    For example, how about having separate IEs for S-VID, C-VID, B-VID
>    and I=SID?  What other IEs are needed for PPP and WiMAX?
> 
> 3. The description of proposed IE dataLinkFrameType seems rather
>    minimal - eventually we'll want to add more data link types.  For
>    example, the ifType-MIB (www.iana.org/assignments/ianaiftype-mib)
>    has a much longer list.  Maybe we have to choose here between a long
>    list of types, each with its own set of fields, or a short list of
>    very general fields?  A short, simple list seems very appealing!

I would propose an extensible IANA sub-registry.

Cheers,
P.

-- 
Paul Aitken
Cisco Systems Ltd, Edinburgh, Scotland.