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Главная страница / Где меня найти В твиттере уже год, так что можно сказать, что я сижу в твиттере довольно давно. Мой аккаунт – @imFlashback. В нем я общаюсь со знакомыми, друзьями и просто пользователями. Я не сильно активен, но 3 твита в день есть, согласно моим рассчетам. Аккаунт же @Zdes_byl_Vasya представляет собой RSS-ленту этого сайта.
В других известных сервиса (ВКонтакте, Одноклассники, Фейсбук, етк) меня нет. Блин, какой-то унылый пост, но че поделаешь.Поделись постом с братишкамиНовый комментарий

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[Bridge] bridging and wireless

Wayback MachineAbout this captureCOLLECTED BY Organization: Alexa Crawls Starting in 1996, Alexa Internet has been donating their crawl data to the Internet Archive. Flowing in every day, these data are added to the Wayback Machine after an embargo period. Collection: Alexa Crawls DD Crawl data donated by Alexa Internet. This data is currently not publicly accessible TIMESTAMPSloadingMark S. Mathewsmark@absoval.com
Mon, 17 Apr 2000 16:41:46 -0400 (EDT)As far as I know, you can’t buy a Lucent card with AP firmware in it, Icould be wrong…I’ve never looked. To bridge successfully with 802.11,the wireless interface needs to be an AP. I’m currently running an AP with a Prism2 card at 11Mb/s using thelinux-wlan-ng code, the Intersil AP firmware (requires a license), kernel2.2.14, and Lennert’s very nice new bridge code. It’s workingbeautifully.I haven’t tried it with the Prism1 code yet, but it should be fine.BTW:I just finished looking through old posts on the bridge list. It lookslike there’s considerable confusion about bridging with 802.11. Wellhere’s one rundown:Background:802.11 frames use a 3 or 4 address header format, what the addressesmean depends on the settings of two other bits in the header, toDS andfromDS. At a minimum, the addresses encode the source address (SA), destination address (DA), and basic service set identifier (BSSID) (orwireless network ID).Here’s a quick table of the address usage in 802.11 data frames:toDS fromDS A1 A2 A3 A4 Note 0 0 DA SA BSSID n/a This is AdHoc mode 0 1 DA BSSID SA n/a Infra mode, from the AP 1 0 BSSID SA DA n/a Infra mode, to the AP 1 1 RA TA DA SA AP to AP communicationIn most circumstances, the first three types are all that is used. Thelast type is when APs wish to send frames between them. It’s also veryuseful when you want to use the wireless medium to bridge between twoWIRED lans. I believe this is what Stuart Lynne has implemented. In mostcases where all of the non-wired wireless nodes (e.g. laptops w/ wirelesscards) are ‘leaf’ nodes, you’ll never need the 4 address format. ===>In 802.11, all directed (non broad/multicast) frames are acknowledged.What this means for bridging is that an 802.11 device cannot send frameswith a Source Address (SA) different from its own. Otherwise, theacknowledgment doesn’t get sent to the right station. This is the problemwith bridging in AdHoc mode.===>Frames to/from 802.11 devices _can_ be bridged. It just requires thatyou use Infrastructure mode and build an 802.11 access point to be yourbridge. In Infrastructure mode, all traffic passes through the accesspoint. Stations always send with the toDS bit set, and the AP alwayssends with the fromDS bit set (see table above). Since all traffic passesthrough the AP, we can successfully bridge that traffic if it isn’tdestined for another wireless node in the same BSS. This is all doneusing the 3 address format. The trick that makes all this work is that inInfrastructure mode, the BSSID _is_ the mac address of the AP’s wirelessinterface. Hence the middle two cases always send the Ack to the addressin A2.What it really boils down to is:—- Are you just bridging between a wireless network of multiple mobile nodes and one wired network? (microcell type setup) If so, the three address format is sufficient.—- Are you trying to set up two half-bridges that are using wireless to get packets back and forth between two wired network? If so, the four address format is the thing to use.BTW: You may be asking yourself “if 802.11 uses a different frame format,how will the ‘ethernet bridge’ code work?”. The answer is…..frameconversion. Most wireless lan cards and/or drivers fake being ethernetdevices. At the very least, at the top edge of the driver, you seeethernet frames.Sorry for the long note. It is intended to inform….it may just confuse.In either case, your welcome and I’m sorry. ;-)-MarkOn Mon, 17 Apr 2000, Derrick J Brashear wrote:> I went through the archive because I was curious what the particular> problem with WaveLAN and bridging was. I’m using a ZoomAIR 802.11 (PRISM,> not PRISM2) card in Access Point (a.k.a. Infra) mode successfully on my> bridge hose; The particulars of the configuration are eth0 (the hardware> ethernet) and eth1 (the ZoomAIR card with the linux-wlan driver) are> bridged and are on my local network, thus I’m routing between ppp0 and> br0 (giving me, effectively, an Apple Airport;-)>> What I learned when I first tried something like this was the 802.11> protocol is apparently acknowledged on a frame level, so when I was trying> to do this with the wireless stuff in Ad-Hoc mode, it didn’t work.>> The wireless client is using a Lucent card, but I don’t know if the Lucent> firmware supports being an Access Point unless the card was bought as> such. (I can find out if anyone cares) The driver appears to support it if> the firmware does.>> -D>>>>> _______________________________________________> Bridge mailing list – Bridge@opensource.captech.com>http://opensource.captech.com/mailman/listinfo/bridge>Mark S. MathewsAbsoluteValue Software Web: http://www.absoval.comP.O. Box 941149 e-mail: mark@absoval.comMaitland, FL 32794-1149 Phone: 407.644.8582USA Fax: 407.539.1294