Re: [DNA-BOF] Re: link "hints"

[montavont <montavont@dpt-info.u-strasbg.fr>]

Hi,

We tried to formalize all the parameters we can put in link hints, as 
you seem to describe,  in
draft-bertin-params-hints-00.txt

It would be good to have a feedback from the BOF in order to enhance 
this draft...

I'll add some comments inline...

Nicolas

Bernard Aboba wrote:

>My understanding was that the relevance of L2 "hints" to DNA was for
>determining whether a change is made in the point of attachment, and
>if so, whether a change of subnet has also taken place.
>
>This is in contrast to other discussions such as in ALIAS, where L2
>information could potentially be used for a much wider range of purposes.
>
>If this perception is correct, then it allows us to focus the conversation
>somewhat.  For example, in IEEE 802.11 we have:
>
>a. Information in the Beacon and Probe Responses.  This can provide the
>host with the capabilities of potential future points of attachment.
>However, it doesn't reliably provide information on the subnets.  Since
>VLAN assignment can be dynamic it might even be argued that such
>information might not be appropriate in the Beacon/Probe Response (unless
>the SSID to VLAN mapping is static).
>
As far as I know, we can not have access to the information contained in 
Beacon and Probe Responses. These messages are treated in the firmware 
of the card. Anyway, some information are forwarded to the driver, and 
only this information is usable.

>
>In some Virtual AP implementations the same BSSID is used with multiple
>SSIDs, so a host attempting to determine whether it is reattaching to the
>same "point of attachment" probably needs to use the combination of the
>BSSID and SSID, rather than just the BSSID alone.
>
I don't understand your point: when you have an AP with multiple SSIDs, 
a MN might determine that it is the same point of attachment with only 
the BSSID.

>
>In future (IEEE 802.11k), the Beacon/Probe Response might provide
>information on neighbor capabilities as well as capabilities of the
>advertising AP.
>
>Note that in some implementations the BSSID (WM MAC Address) is the same
>as the DS MAC address; in others the DS MAC address is distinct.
>
>b. Association/Reassociation.  IEEE 802.11i has two association
>exchanges (an insecure one using 802.11 management frames, and a secure
>one using the 4-way handshake).  In general, where both are available, the
>completion of "secure association" is used as the "hint" that kicks off
>DNA.  Today the "secure association" provides the SSID, but in future
>it might provide prefix/subnet information as well.
>
>c. Radio measurements.  This can include a wide spectrum of things under
>consideration in IEEE 802.11k, including measurements of signal strength,
>S/N ratio, packet loss, jitter, etc.  While many of these things might be
>relevant to roaming or load balancing decisions, they don't appear
>relevant to DNA in that they don't provide "hints" relating to the network
>topology of a potential point of attachment.
>
The radio measurements are typically the parameters we define in our 
draft. Do you think we miss some ?

>
>
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