Thread: [Madwifi-devel] Auto ack timeout
Status: Beta
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From: Hasan R. <ha...@di...> - 2009-05-08 18:43:03
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Hi All, I am trying to figure out a way to have the AP automatically set the ack timeout value based on the "detected" distance of the farthest client connected to it. Basically that way if a new client is say about 10 miles from the AP, then the AP would automatically adjust the ack timeout to accommodate that client. I am thinking perhaps I can use the difference deduced from the time stamps of the ACKs and use it to calculate the distance. Not exactly sure how, but it's a rough idea. Has anyone done anything similar, any ideas, thoughts? TIA! Hasan R. |
From: Derek S. <de...@in...> - 2009-05-08 21:38:19
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Hi, Add a new IE to the beacon which includes the GPS coordinates of the source node. On receipt of the beacon, the receiving node works out the distance between and determines the distance between and adjusts the ack timeout accordingly. If the current ack timeout is too short a value, you cannot use standard TCP/UDP like comms to setup a link - link setup has to be via broadcast packets. With too short a ack value, the link cannot be established to a new remote node as the packets are never acknowledged as the ack timeout is too small. Derek. On Fri, 8 May 2009, Hasan Rashid wrote: > > Hi All, > > > > I am trying to figure out a way to have the AP automatically set the ack > timeout value based on the “detected” distance of the farthest client > connected to it. Basically that way if a new client is say about 10 miles > from the AP, then the AP would automatically adjust the ack timeout to > accommodate that client. I am thinking perhaps I can use the difference > deduced from the time stamps of the ACKs and use it to calculate the > distance. Not exactly sure how, but it’s a rough idea. > > > > Has anyone done anything similar, any ideas, thoughts? > > > > TIA! > > > > Hasan R. > > > -- Derek Smithies Ph.D. IndraNet Technologies Ltd. Email: de...@in... ph +64 3 365 6485 Web: http://www.indranet-technologies.com/ |
From: Hasan R. <ha...@di...> - 2009-05-16 00:03:31
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Derek, Hmm... here is the thing, that still requires manual configuration. I am thinking more along the lines of having it start at the highest value (409 I believe?) and work its way down. The process should repeat every time a device has been associated. This is something I probably will need to implement in the HAL, I'll see! Anyways, thank you for your input. - Hasan R. -----Original Message----- From: Derek Smithies [mailto:de...@in...] Sent: Friday, May 08, 2009 2:38 PM To: Hasan Rashid Cc: mad...@li... Subject: Re: [Madwifi-devel] Auto ack timeout Hi, Add a new IE to the beacon which includes the GPS coordinates of the source node. On receipt of the beacon, the receiving node works out the distance between and determines the distance between and adjusts the ack timeout accordingly. If the current ack timeout is too short a value, you cannot use standard TCP/UDP like comms to setup a link - link setup has to be via broadcast packets. With too short a ack value, the link cannot be established to a new remote node as the packets are never acknowledged as the ack timeout is too small. Derek. On Fri, 8 May 2009, Hasan Rashid wrote: > > Hi All, > > > > I am trying to figure out a way to have the AP automatically set the ack > timeout value based on the “detected” distance of the farthest client > connected to it. Basically that way if a new client is say about 10 miles > from the AP, then the AP would automatically adjust the ack timeout to > accommodate that client. I am thinking perhaps I can use the difference > deduced from the time stamps of the ACKs and use it to calculate the > distance. Not exactly sure how, but it’s a rough idea. > > > > Has anyone done anything similar, any ideas, thoughts? > > > > TIA! > > > > Hasan R. > > > -- Derek Smithies Ph.D. IndraNet Technologies Ltd. Email: de...@in... ph +64 3 365 6485 Web: http://www.indranet-technologies.com/ |
From: Derek S. <de...@in...> - 2009-05-16 00:37:00
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Hi, Nope... Just a bit of clever code.. Every node sends out annoucement beacons of some sort. On receipt of an annoucement beacon, the recipient checks that the sender is known. If not known: The recipient tries to establish communication with the sender. The recipient modifies the acktimeout until communication is established /broken. If you are running adhoc mode, you simply wait for when a remote node is added to your neighbour table. ((The remote node is added on receipt of a standard 802.11 beacon)) - and then you attempt to establish communication with different ack timeouts. Thus, - it can be done automatically... Derek. On Fri, 15 May 2009, Hasan Rashid wrote: > Derek, > > Hmm... here is the thing, that still requires manual configuration. I am > thinking more along the lines of having it start at the highest value > (409 I believe?) and work its way down. The process should repeat every > time a device has been associated. This is something I probably will > need to implement in the HAL, I'll see! > > Anyways, thank you for your input. > > - Hasan R. > > > -----Original Message----- > From: Derek Smithies [mailto:de...@in...] > Sent: Friday, May 08, 2009 2:38 PM > To: Hasan Rashid > Cc: mad...@li... > Subject: Re: [Madwifi-devel] Auto ack timeout > > Hi, > Add a new IE to the beacon which includes the GPS coordinates of the > source node. > On receipt of the beacon, the receiving node works out the distance > between and determines the distance between and adjusts the ack timeout > accordingly. > > If the current ack timeout is too short a value, you cannot use standard > TCP/UDP like comms to setup a link - link setup has to be via broadcast > packets. With too short a ack value, the link cannot be established to a > new remote node as the packets are never acknowledged as the ack timeout > is too small. > > Derek. > > On Fri, 8 May 2009, Hasan Rashid wrote: > >> >> Hi All, >> >> >> >> I am trying to figure out a way to have the AP automatically set the ack >> timeout value based on the “detected” distance of the farthest client >> connected to it. Basically that way if a new client is say about 10 miles >> from the AP, then the AP would automatically adjust the ack timeout to >> accommodate that client. I am thinking perhaps I can use the difference >> deduced from the time stamps of the ACKs and use it to calculate the >> distance. Not exactly sure how, but it’s a rough idea. >> >> >> >> Has anyone done anything similar, any ideas, thoughts? >> >> >> >> TIA! >> >> >> >> Hasan R. >> >> >> > > -- Derek Smithies Ph.D. IndraNet Technologies Ltd. Email: de...@in... ph +64 3 365 6485 Web: http://www.indranet-technologies.com/ |
From: Hasan R. <ha...@di...> - 2009-05-16 20:48:54
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Right, I mean by manual configuration I meant making the repeaters aware of the GPS co-ordinates, hence the installers in the field would've to input that information. This is basically for WDS Repeaters in the network. But, yes I was thinking along the same lines of taking the 80211 node beacons upon association and re-establishing the highest ack timeout value. I was considering hardware levels ACKs, but that was to keep all options on the table. Good talk! - Hasan R. > Hi, > Nope... > > Just a bit of clever code.. > Every node sends out annoucement beacons of some sort. > > On receipt of an annoucement beacon, the recipient checks that the > sender is known. If not known: > The recipient tries to establish communication with the sender. > The recipient modifies the acktimeout until communication is > established > /broken. > > If you are running adhoc mode, you simply wait for when a remote node is > added to your neighbour table. ((The remote node is added on receipt of a > standard 802.11 beacon)) - and then you attempt to establish communication > with different ack timeouts. > > Thus, - it can be done automatically... > > Derek. > > On Fri, 15 May 2009, Hasan Rashid wrote: > >> Derek, >> >> Hmm... here is the thing, that still requires manual configuration. I am >> thinking more along the lines of having it start at the highest value >> (409 I believe?) and work its way down. The process should repeat every >> time a device has been associated. This is something I probably will >> need to implement in the HAL, I'll see! >> >> Anyways, thank you for your input. >> >> - Hasan R. >> >> >> -----Original Message----- >> From: Derek Smithies [mailto:de...@in...] >> Sent: Friday, May 08, 2009 2:38 PM >> To: Hasan Rashid >> Cc: mad...@li... >> Subject: Re: [Madwifi-devel] Auto ack timeout >> >> Hi, >> Add a new IE to the beacon which includes the GPS coordinates of the >> source node. >> On receipt of the beacon, the receiving node works out the distance >> between and determines the distance between and adjusts the ack timeout >> accordingly. >> >> If the current ack timeout is too short a value, you cannot use standard >> TCP/UDP like comms to setup a link - link setup has to be via broadcast >> packets. With too short a ack value, the link cannot be established to >> a >> new remote node as the packets are never acknowledged as the ack timeout >> is too small. >> >> Derek. >> >> On Fri, 8 May 2009, Hasan Rashid wrote: >> >>> >>> Hi All, >>> >>> >>> >>> I am trying to figure out a way to have the AP automatically set the >>> ack >>> timeout value based on the âdetectedâ distance of the farthest >>> client >>> connected to it. Basically that way if a new client is say about 10 >>> miles >>> from the AP, then the AP would automatically adjust the ack timeout to >>> accommodate that client. I am thinking perhaps I can use the difference >>> deduced from the time stamps of the ACKs and use it to calculate the >>> distance. Not exactly sure how, but itâs a rough idea. >>> >>> >>> >>> Has anyone done anything similar, any ideas, thoughts? >>> >>> >>> >>> TIA! >>> >>> >>> >>> Hasan R. >>> >>> >>> >> >> > > -- > Derek Smithies Ph.D. > IndraNet Technologies Ltd. > Email: de...@in... > ph +64 3 365 6485 > Web: http://www.indranet-technologies.com/ > -- Regards, Hasan Rashid Embedded Systems Software Engineer DigiatlPath, Inc |