[Fwd: delay in adhoc mode]

Lukic lukic
Sun Jul 20 23:47:18 PDT 2003


> 1. The BSSID will be all zeros.
> 2. There is no distributed beaconing mechanism
> 3. As long as the cards on the same channel and within ....
> 4. A card in PIM will not send out any management ......

that's true

> 5. A card in PIM will still send ACK for received management frames
> (not sure).
> The further question is: what is the impact on the nearby 802.11 IBSS
>   communication?

I tested it yesterday and 802.11 IBSS won in getting bandwidth, this means,
that i ran flood ping on both connections and thanks to 802.11 IBSS retry on
corrupted packets, this connection after a short time got all of bandwidth
and pseudo IBSS connection had lost it :-( This was the state with 1450byte
packet flood. So you will need clear channel or very strong signal or send
very small packets.

> 6. Are the Control frames the same as those in 802.11?

I think that there are none.

> 7. How do the two cards in PIM set up the communication? Because these
> is no beacon, how does the sender find out the destination MAC address?
>   Does it mean that most of the messages are broadcasted to the current
>   channel and the IP layer decide whether it should "receive" the data?

Yes, it's like classic cable ethernet.

> 8.How does a card know if there is other card around, and what is the
> collision avoid mechanism?  Is it the same as other mode (802.11 way)?

My measurements are saying, that there is no CA mechanism :-( All have on
manage TCP/IP protocol

> 9.As there is no management frame any more, how does a card know some
> basic physical layer stuffs such as the rate?

It sends on rate you set and try to decode every rate, but sometimes this is
in troubles, so i recomend to set the same rate on every card.


Lukic

N49? 02,40' E19? 43,07'






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