c****n
发帖数: 21367 | 1 用户奔出去一个udp broadcast包，AP会负责收了再发吗？ | z*****n
发帖数: 7639 | 2 what do you mean?
AP is usually connected to a LAN, which is by
default a broadcast domain.
Talking about broadcasting, there are two different
broadcastings at different network layers:
An Ethernet itself is a broadcast domain, which
mean all the frames on one segment of LAN will
be heard and received by all the nodes. After
the receiving, the LAN card of each node will
compare the "destination MAC address" in the
frame header with its own, if they match, the
frame is decapsulated and data fiel
【在 c****n 的大作中提到】
: 用户奔出去一个udp broadcast包，AP会负责收了再发吗？
| c****n
发帖数: 21367 | 3 I mean by UDP, user send to xx.xx.xx.255 (assume the LAN is /24)
would the AP get it and resend it ?
from your answer, it seems the answer is yes
then, i raise another question, if the user send out a broadcast
MAC frame (to FF:FF:FF...), would the AP re-broadcast it?
thanks
【在 z*****n 的大作中提到】
: what do you mean?
: AP is usually connected to a LAN, which is by
: default a broadcast domain.
: Talking about broadcasting, there are two different
: broadcastings at different network layers:
: An Ethernet itself is a broadcast domain, which
: mean all the frames on one segment of LAN will
: be heard and received by all the nodes. After
: the receiving, the LAN card of each node will
: compare the "destination MAC address" in the
| z*****n
发帖数: 7639 | 4 in both cases the AP will retransmit (actually rebroadcast)
the frame. AP is a device should not sink any data packet.
【在 c****n 的大作中提到】
: I mean by UDP, user send to xx.xx.xx.255 (assume the LAN is /24)
: would the AP get it and resend it ?
: from your answer, it seems the answer is yes
: then, i raise another question, if the user send out a broadcast
: MAC frame (to FF:FF:FF...), would the AP re-broadcast it?
: thanks
| c****n
发帖数: 21367 | 5 do we know any AP that can be modified to not rebroadcast the frame?
that would be very helpful, thx
【在 z*****n 的大作中提到】
: in both cases the AP will retransmit (actually rebroadcast)
: the frame. AP is a device should not sink any data packet.
| z*****n
发帖数: 7639 | 6 make an AP of your own...
Actually I don't know why you need this function.
You can always set up encryption for your WLAN
so that nothing can be eavesdropped.
【在 c****n 的大作中提到】
: do we know any AP that can be modified to not rebroadcast the frame?
: that would be very helpful, thx
| c****n
发帖数: 21367 | 7 oh, well... not for that purpose
i just want my experimental nodes to be able to do the
experiement (use broadcast frame) and set up easily (AP is easier
to set up than ad-hoc and requires no routing tool such as MS mesh)
any hint? :)
【在 z*****n 的大作中提到】
: make an AP of your own...
: Actually I don't know why you need this function.
: You can always set up encryption for your WLAN
: so that nothing can be eavesdropped.
| z*****n
发帖数: 7639 | 8 As I have said, all the frames you send to an AP are
physically broadcast to the wireless channel. The AP
should not hold or block any frame.
Correspondingly, all the wireless nodes will receive
whatever on the radio channel. After the reception,
the node proceeds as following logic:
1. Check CRC, if result fails, drop the frame. otherwise
2. Check the "Type/subtype" field in the "frame control"
field. Depends on the type of this frame, different
processes are followed.
Maybe you need to clearif
【在 c****n 的大作中提到】
: oh, well... not for that purpose
: i just want my experimental nodes to be able to do the
: experiement (use broadcast frame) and set up easily (AP is easier
: to set up than ad-hoc and requires no routing tool such as MS mesh)
: any hint? :)
| c****n
发帖数: 21367 | 9 thank you for your kind apply, i learnt a lot. :)
yes, i want an AP which does everything in normal but
not rebroadcast any broadcast data frame.
it generally serves the following two purposes:
1. function as an AP normally and can associate many stations
and do all kinds of transfers
2. when stations are sending broadcast frames (which is the
only frame i would use for my experiment), AP do not re-trans
this makes the experimental network much easier to maintain
and setup. :)
my question is: is
【在 z*****n 的大作中提到】
: As I have said, all the frames you send to an AP are
: physically broadcast to the wireless channel. The AP
: should not hold or block any frame.
: Correspondingly, all the wireless nodes will receive
: whatever on the radio channel. After the reception,
: the node proceeds as following logic:
: 1. Check CRC, if result fails, drop the frame. otherwise
: 2. Check the "Type/subtype" field in the "frame control"
: field. Depends on the type of this frame, different
: processes are followed.
| z*****n
发帖数: 7639 | 10 MAC layer logic is solidated as firmware in an
AP ASIC. I am sorry I don't know any product on
which you can realize your idea... You need the
source code of MAC protocol for that specific
ASIC and a specific loader to write your version
in...
Maybe a better solution is to find a 802.11 transceiver
and write the MAC logic yourself and interface it
through a general purpose microcontroller.
If this is your destination, you can check MAX2830,
which is a front-end WLAN transceiver.
【在 c****n 的大作中提到】
: thank you for your kind apply, i learnt a lot. :)
: yes, i want an AP which does everything in normal but
: not rebroadcast any broadcast data frame.
: it generally serves the following two purposes:
: 1. function as an AP normally and can associate many stations
: and do all kinds of transfers
: 2. when stations are sending broadcast frames (which is the
: only frame i would use for my experiment), AP do not re-trans
: this makes the experimental network much easier to maintain
: and setup. :)
| c****n
发帖数: 21367 | 11 hehe ,thanks :) i might as well just use ad-hoc mode :)
【在 z*****n 的大作中提到】
: MAC layer logic is solidated as firmware in an
: AP ASIC. I am sorry I don't know any product on
: which you can realize your idea... You need the
: source code of MAC protocol for that specific
: ASIC and a specific loader to write your version
: in...
: Maybe a better solution is to find a 802.11 transceiver
: and write the MAC logic yourself and interface it
: through a general purpose microcontroller.
: If this is your destination, you can check MAX2830,
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