Re: Passive/Active scanning information

RobertGrandl <RobertGrandl.2sgiso@no-mx.wirelessforums.org> hath
wroth:

>I have some question related to 802.11 handoff mechanism.

None of your questions have anything to do with handoff (roaming).

>1. Does anybody know more information about TIM related field from
>beacon frame format, and how is modeled information offered by it. I
>read from IEEE 802.11 standards, but I didn't understand so well.

TIM broadcasts are used for power management, where the client power
is shut off for an interval when the access point is going to be busy
servicing other clients. Only clients that have power save mode
enabled will react to the TIM interval. Most clients run in power
save mode = off because it impacts performance. Note that it is not
the same as the ATIM interval, which is just the beacon interval.

This might be a bit simpler than the IEEE 802.11 specs, which tend to
turn the brain into mush.
<http://www.wi-fiplanet.com/tutorials/article.php/1015781>
<http://www.wi-fiplanet.com/tutorials/article.php/1492071>
Also, search Google for "TIM interval" and "traffic indication map".

>2. If my NETGEAR WAG511 drivers is in monitor mode, can I send probe
>request?

You can send probe requests in any mode you feel like. It's the first
packets that get sent when initiating a new connection in any mode
asking essentially "who is out there"? It's also the way Netstumbler
works.

>Also, it's another mode where I can use passive scanning, but also send
>traffic?
>I suppose in monitor mode, doesn't want to work, no?

Dunno. Probably not. Trying to seperate valid incoming data from
sniffed data is going to be a challenge.

>3. If I can't send data traffic in monitor mode, why I can send ping
>packages.

Dunno. I have no idea what you are doing or trying to accomplish.

>What kind of ICMP traffic is ping pong?

See RFC792. ICMP type list:
<http://www.iana.org/assignments/icmp-parameters>

>NAME TYPE CODE COMMENT
>ICMP_ECHO 8 0 /* Ping. */
>ICMP_ECHOREPLY 0 0 /* Ping response. */
>ICMP_UNREACH 3 4 /* ICMP_UNREACH_NEEDFRAG - Used by Path */
> /* MTU to determine the optimal MTU setting. */
>ICMP_TIMXCEED 11 0 /* TTL expired in transit. Used by UNIX */
> /* traceroute and Windows tracert. Note that */
> /* UNIX traceroute also uses a high UDP port. */
> /* This message is also important when */
> /* routing loops occur. */

Note that there is also UDP Ping.



>
>Thanks in advance,
>Robert
>
>
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--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Thank you very much Jeff for your amability.
Indeed wireless standard documentation sometimes it's not the best to understand some specific and exactly problems.

Thanks,
Robert