X*r
2 楼
no
【在 w******t 的大作中提到】
: 是不是跟手机一样上下行链路的频带分开了？
【在 w******t 的大作中提到】
: 是不是跟手机一样上下行链路的频带分开了？
z*n
3 楼
No, the same frequency.
802.11 uses CSMA scheme to schedule the transmissions.
【在 w******t 的大作中提到】
: 是不是跟手机一样上下行链路的频带分开了？
802.11 uses CSMA scheme to schedule the transmissions.
【在 w******t 的大作中提到】
: 是不是跟手机一样上下行链路的频带分开了？
w*t
4 楼
802.11 和 802.15.4频谱部分是重叠的。有什么办法避免两者的竞争吗？
【在 z*****n 的大作中提到】
: No, the same frequency.
: 802.11 uses CSMA scheme to schedule the transmissions.
【在 z*****n 的大作中提到】
: No, the same frequency.
: 802.11 uses CSMA scheme to schedule the transmissions.
z*n
5 楼
If you can manually select the channels, this is
a trivial problem.
【在 w******t 的大作中提到】
: 802.11 和 802.15.4频谱部分是重叠的。有什么办法避免两者的竞争吗？
a trivial problem.
【在 w******t 的大作中提到】
: 802.11 和 802.15.4频谱部分是重叠的。有什么办法避免两者的竞争吗？
i*f
6 楼
Then in infrastructure mode. The AP needs to forward all the traffic in the
WLAN, using the same contention scheme? Isn't it unfair for the AP?
【在 z*****n 的大作中提到】
: No, the same frequency.
: 802.11 uses CSMA scheme to schedule the transmissions.
WLAN, using the same contention scheme? Isn't it unfair for the AP?
【在 z*****n 的大作中提到】
: No, the same frequency.
: 802.11 uses CSMA scheme to schedule the transmissions.
X*r
7 楼
that is why it is called AP
others just nodes
enjoy a decent and high title and pays off
the
【在 i*****f 的大作中提到】
: Then in infrastructure mode. The AP needs to forward all the traffic in the
: WLAN, using the same contention scheme? Isn't it unfair for the AP?
others just nodes
enjoy a decent and high title and pays off
the
【在 i*****f 的大作中提到】
: Then in infrastructure mode. The AP needs to forward all the traffic in the
: WLAN, using the same contention scheme? Isn't it unfair for the AP?
i*f
8 楼
But what it pays off is not its own data. AP is forwarding other nodes data
in the WLAN.
So i think AP's accessing to the channel should be garanteed, but it SEEMS
AP doesn't get any priority to its subscribers in the WLAN.
Is this the trueth or I misunderstand something in the standard???
【在 X*****r 的大作中提到】
: that is why it is called AP
: others just nodes
: enjoy a decent and high title and pays off
:
: the
in the WLAN.
So i think AP's accessing to the channel should be garanteed, but it SEEMS
AP doesn't get any priority to its subscribers in the WLAN.
Is this the trueth or I misunderstand something in the standard???
【在 X*****r 的大作中提到】
: that is why it is called AP
: others just nodes
: enjoy a decent and high title and pays off
:
: the
X*r
9 楼
true
data
【在 i*****f 的大作中提到】
: But what it pays off is not its own data. AP is forwarding other nodes data
: in the WLAN.
: So i think AP's accessing to the channel should be garanteed, but it SEEMS
: AP doesn't get any priority to its subscribers in the WLAN.
: Is this the trueth or I misunderstand something in the standard???
data
【在 i*****f 的大作中提到】
: But what it pays off is not its own data. AP is forwarding other nodes data
: in the WLAN.
: So i think AP's accessing to the channel should be garanteed, but it SEEMS
: AP doesn't get any priority to its subscribers in the WLAN.
: Is this the trueth or I misunderstand something in the standard???
c*n
10 楼
in most of the time, AP doesn't have its "own" data...
the most commonly seen AP is a wireless router... how much traffic
itself will generate?
data
【在 i*****f 的大作中提到】
: But what it pays off is not its own data. AP is forwarding other nodes data
: in the WLAN.
: So i think AP's accessing to the channel should be garanteed, but it SEEMS
: AP doesn't get any priority to its subscribers in the WLAN.
: Is this the trueth or I misunderstand something in the standard???
the most commonly seen AP is a wireless router... how much traffic
itself will generate?
data
【在 i*****f 的大作中提到】
: But what it pays off is not its own data. AP is forwarding other nodes data
: in the WLAN.
: So i think AP's accessing to the channel should be garanteed, but it SEEMS
: AP doesn't get any priority to its subscribers in the WLAN.
: Is this the trueth or I misunderstand something in the standard???
i*f
11 楼
I didn't mean that it's not fair for AP ITSELF.
See, suppose the WLAN is very heavy-loaded. And all the traffic's
destination is in the WLAN (i.e., other nodes in the WLAN).
If the AP's chance to access the channel is the same as a normal node. It
seems that AP will never be able to forward all this traffic.
【在 c****n 的大作中提到】
: in most of the time, AP doesn't have its "own" data...
: the most commonly seen AP is a wireless router... how much traffic
: itself will generate?
:
: data
See, suppose the WLAN is very heavy-loaded. And all the traffic's
destination is in the WLAN (i.e., other nodes in the WLAN).
If the AP's chance to access the channel is the same as a normal node. It
seems that AP will never be able to forward all this traffic.
【在 c****n 的大作中提到】
: in most of the time, AP doesn't have its "own" data...
: the most commonly seen AP is a wireless router... how much traffic
: itself will generate?
:
: data
c*n
12 楼
what's the unfairness then? everyone needs the AP forwarding
both the data and ACK
【在 i*****f 的大作中提到】
: I didn't mean that it's not fair for AP ITSELF.
: See, suppose the WLAN is very heavy-loaded. And all the traffic's
: destination is in the WLAN (i.e., other nodes in the WLAN).
: If the AP's chance to access the channel is the same as a normal node. It
: seems that AP will never be able to forward all this traffic.
both the data and ACK
【在 i*****f 的大作中提到】
: I didn't mean that it's not fair for AP ITSELF.
: See, suppose the WLAN is very heavy-loaded. And all the traffic's
: destination is in the WLAN (i.e., other nodes in the WLAN).
: If the AP's chance to access the channel is the same as a normal node. It
: seems that AP will never be able to forward all this traffic.
X*r
13 楼
he/she means the unfairness between AP and clients
【在 c****n 的大作中提到】
: what's the unfairness then? everyone needs the AP forwarding
: both the data and ACK
【在 c****n 的大作中提到】
: what's the unfairness then? everyone needs the AP forwarding
: both the data and ACK
X*r
14 楼
as I told you, it is the DESTINY of the AP
like pigs, most of them got food since they will be your food someday
unfair, isn't it?
APs are like pigs, their lives are predetermined, i.e., serving people, when
they are created/breeded
it is unfair, i agree...
【在 i*****f 的大作中提到】
: I didn't mean that it's not fair for AP ITSELF.
: See, suppose the WLAN is very heavy-loaded. And all the traffic's
: destination is in the WLAN (i.e., other nodes in the WLAN).
: If the AP's chance to access the channel is the same as a normal node. It
: seems that AP will never be able to forward all this traffic.
like pigs, most of them got food since they will be your food someday
unfair, isn't it?
APs are like pigs, their lives are predetermined, i.e., serving people, when
they are created/breeded
it is unfair, i agree...
【在 i*****f 的大作中提到】
: I didn't mean that it's not fair for AP ITSELF.
: See, suppose the WLAN is very heavy-loaded. And all the traffic's
: destination is in the WLAN (i.e., other nodes in the WLAN).
: If the AP's chance to access the channel is the same as a normal node. It
: seems that AP will never be able to forward all this traffic.
i*f
15 楼
ok, forget the 'fairness' issue. I used an impropriate word.
How to explain/solve the scenario I described (assumed) in the previous post?
or that's the actuall case.
P.S., i'm a he :)
【在 c****n 的大作中提到】
: what's the unfairness then? everyone needs the AP forwarding
: both the data and ACK
How to explain/solve the scenario I described (assumed) in the previous post?
or that's the actuall case.
P.S., i'm a he :)
【在 c****n 的大作中提到】
: what's the unfairness then? everyone needs the AP forwarding
: both the data and ACK
X*r
16 楼
that is the way it is
and that is the bottleneck of WLAN
post?
【在 i*****f 的大作中提到】
: ok, forget the 'fairness' issue. I used an impropriate word.
: How to explain/solve the scenario I described (assumed) in the previous post?
: or that's the actuall case.
: P.S., i'm a he :)
and that is the bottleneck of WLAN
post?
【在 i*****f 的大作中提到】
: ok, forget the 'fairness' issue. I used an impropriate word.
: How to explain/solve the scenario I described (assumed) in the previous post?
: or that's the actuall case.
: P.S., i'm a he :)
i*f
17 楼
Yes, bottleneck, that's what i what to say, hehe
【在 X*****r 的大作中提到】
: that is the way it is
: and that is the bottleneck of WLAN
:
: post?
【在 X*****r 的大作中提到】
: that is the way it is
: and that is the bottleneck of WLAN
:
: post?
c*n
18 楼
it is simply true you can physically jam a WLAN using a laptop only
what's the problem?
post?
【在 i*****f 的大作中提到】
: ok, forget the 'fairness' issue. I used an impropriate word.
: How to explain/solve the scenario I described (assumed) in the previous post?
: or that's the actuall case.
: P.S., i'm a he :)
what's the problem?
post?
【在 i*****f 的大作中提到】
: ok, forget the 'fairness' issue. I used an impropriate word.
: How to explain/solve the scenario I described (assumed) in the previous post?
: or that's the actuall case.
: P.S., i'm a he :)
X*r
19 楼
how？
【在 c****n 的大作中提到】
: it is simply true you can physically jam a WLAN using a laptop only
: what's the problem?
:
: post?
【在 c****n 的大作中提到】
: it is simply true you can physically jam a WLAN using a laptop only
: what's the problem?
:
: post?
i*f
20 楼
no you can't jam a WLAN with a laptop if it uses PCF
【在 c****n 的大作中提到】
: it is simply true you can physically jam a WLAN using a laptop only
: what's the problem?
:
: post?
【在 c****n 的大作中提到】
: it is simply true you can physically jam a WLAN using a laptop only
: what's the problem?
:
: post?
c*n
21 楼
keep sending signals
【在 X*****r 的大作中提到】
: how？
【在 X*****r 的大作中提到】
: how？
c*n
22 楼
keep sending signals
【在 i*****f 的大作中提到】
: no you can't jam a WLAN with a laptop if it uses PCF
【在 i*****f 的大作中提到】
: no you can't jam a WLAN with a laptop if it uses PCF
i*f
23 楼
PCF
【在 c****n 的大作中提到】
: keep sending signals
【在 c****n 的大作中提到】
: keep sending signals
X*r
24 楼
no
you can not capture the channel for ever
everyone with the same traffic load should have stochastically equal
opportunity
【在 c****n 的大作中提到】
: keep sending signals
you can not capture the channel for ever
everyone with the same traffic load should have stochastically equal
opportunity
【在 c****n 的大作中提到】
: keep sending signals
c*n
25 楼
who cares your rts/cts? keep sending
【在 i*****f 的大作中提到】
: PCF
【在 i*****f 的大作中提到】
: PCF
i*f
26 楼
ok i got you. 很好很强大 @@
【在 c****n 的大作中提到】
: who cares your rts/cts? keep sending
【在 c****n 的大作中提到】
: who cares your rts/cts? keep sending
c*n
27 楼
what if the laptop just ignore the rules?
【在 X*****r 的大作中提到】
: no
: you can not capture the channel for ever
: everyone with the same traffic load should have stochastically equal
: opportunity
【在 X*****r 的大作中提到】
: no
: you can not capture the channel for ever
: everyone with the same traffic load should have stochastically equal
: opportunity
X*r
28 楼
well
if the attacker does not follow 821.11
yes, you are right
but this is the problem of CSMA/CA
【在 c****n 的大作中提到】
: who cares your rts/cts? keep sending
if the attacker does not follow 821.11
yes, you are right
but this is the problem of CSMA/CA
【在 c****n 的大作中提到】
: who cares your rts/cts? keep sending
c*n
29 楼
:) if everyone's in csma/ca, no problem even if in dcf
because everyone's contention windows would grow up
and the maximum contention windows size corresponds to the
maximum number of nodes allowd to associate with one AP
【在 X*****r 的大作中提到】
: well
: if the attacker does not follow 821.11
: yes, you are right
: but this is the problem of CSMA/CA
because everyone's contention windows would grow up
and the maximum contention windows size corresponds to the
maximum number of nodes allowd to associate with one AP
【在 X*****r 的大作中提到】
: well
: if the attacker does not follow 821.11
: yes, you are right
: but this is the problem of CSMA/CA
z*n
30 楼
There are two versions for AP:
802.11 DCF and 802.11PCF
in the original mode AP acts exactly the same as other
nodes(mobile stations), in this case AP is potentially
a bottleneck of the system.
802.11PCF is aimed to solve this problem. In PCF, AP
usually waits a less interframe gap than other nodes,
thus giving AP an advantage to catch the channel.
the
【在 i*****f 的大作中提到】
: Then in infrastructure mode. The AP needs to forward all the traffic in the
: WLAN, using the same contention scheme? Isn't it unfair for the AP?
802.11 DCF and 802.11PCF
in the original mode AP acts exactly the same as other
nodes(mobile stations), in this case AP is potentially
a bottleneck of the system.
802.11PCF is aimed to solve this problem. In PCF, AP
usually waits a less interframe gap than other nodes,
thus giving AP an advantage to catch the channel.
the
【在 i*****f 的大作中提到】
: Then in infrastructure mode. The AP needs to forward all the traffic in the
: WLAN, using the same contention scheme? Isn't it unfair for the AP?
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