Capwap Mailing List: Re: Last call comments for capwap-protocol-binding-ieee80211-07

[Clint Chaplin (clint.chaplin]

On 8/7/08, Pasi.Eronen [at] nokia.com <Pasi.Eronen [at] nokia.com> wrote:
> Pat Calhoun wrote:
>
>  > > I was under the impression that 802 (or at least 802.11) required
>  > > (or assumed) strict in-order delivery -- but perhaps I remember
>  > > this wrong?  (Obvious, tunneling over arbitrary IP hops doesn't
>  > > guarantee in-order delivery, and it seems the data channel doesn't
>  > > have mechanisms to reorder or drop out-of-order packets.)
>
>  > The MAC layer will provide guaranteed delivery at the AP, but
>  > remember that the air isn't exactly a reliable medium. The AP is
>  > then responsible for tunneling the packets. For open or when crypto
>  > is provided at the WTP, there are no issues with re-ordering. When
>  > crypto is provided at the AC, both TKIP and AES have no ordering
>  > requirements, so that is also not an issue.
>
>
> IEEE 802.11 spec talks about the possibility that the higher layer
>  protocol (run on top of 802?) would require in-order delivery (IP
>  doesn't, of course), and seems to be able to provide strict in-order
>  delivery.
>
>  It might be at least good to discuss this topic in the spec
>  (describing that CAPWAP might not be able to provide fully faithful
>  802.11 implementation in Split MAC mode, but that this doesn't matter
>  for most practical purposes when you're running TCP/IP).
>
>

Just because you are running TCP/IP as your main protocol doesn't
guarantee that it's the only protocol.  DNS, DHCP, UDP/IP and others
may be necessary to support running TCP/IP.

Now, do all those other support protocols not care about out-of-order
delivery?  I don't know the answer to that question.
-- 
Clint (JOATMON) Chaplin
Principal Engineer
Corporate Standardization (US)
SISA