Thought as much but was hoping it might have been an issue further up the stack. Anyone know if the number of retransmits can be adjusted or if there are any other tweaks to make the impact minimal?
-----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of David Sovereen Sent: 03 June 2006 14:46 To: WISPA General List Subject: Re: [WISPA] Mikrotik Virtual AP Hi Paul, It's an RF problem. 802.11a/b/g and Nstreme all have packet acknowledgement in the protocol. Every packet your AP sends needs to be acknowledged by the client. When a packet is not acknowledged, the AP retransmits it. Because of poor RF conditions (NLOS), RF/wireless ethernet packets are being lost. When this happens, the AP retransmits the unacknowledged packets automatically. When you see packet loss at the IP layer (i.e. ping timeout), your packet has been lost and retransmitted at the RF/wireless ethernet layer by the AP many times over again. Retransmissions take up significant air time because your AP is waiting until the Ack timeout, typically up to 400usec, for the Acknowledgement to come back and isn't transmitting anything else during that time. It retransmits the packet over and over. One packet like this isn't in itself a problem. But when it happens on a data stream of 20 packets/sec, it is! Because your AP is trying and waiting and trying and waiting to get these packets through, other customers are being impacted. Moving this customer to a Virtual AP will have zero affect. The same packet acknowledgement/transmission problem will occur, and all customers, regardless of SSID will be affected. Your best move is to drop this customer, or if you really want to keep the customer and not impact your other customers, move him to another radio/antenna. RF packet loss is costly in terms of overall AP capacity. Keeping customers who have significant RF packet loss can cut total AP capacity in half or worse, depending on severity. Regards, Dave 989-837-3790 x 151 989-837-3780 fax [EMAIL PROTECTED] www.mercury.net 129 Ashman St, Midland, MI 48640 ----- Original Message ----- From: "Paul Hendry" <[EMAIL PROTECTED]> To: "'WISPA General List'" <firstname.lastname@example.org> Sent: Saturday, June 03, 2006 9:21 AM Subject: [WISPA] Mikrotik Virtual AP Ola, I currently have a scenario where a dozen clients are connected to a 5.8GHz AP where one is a NLOS link. The link quality is fine for this client during normal conditions but when it rains it becomes a little unstable which the customer is fine with as they have no alternative. The problem that I have is when the weather is poor it can cause a lot of jitter to the other clients on the same AP especially when the NLOS link is trying to be used. I’m wondering if this is an RF or IP issue. If it’s an issue at the IP layer then I wonder if setting up a Mikrotik box as the AP with a virtual AP for the NLOS link and a virtual AP for the rest would get round this problem. Any thoughts or experiences?? Cheers, P Skyline Networks & Consultancy Ltd Web: HYPERLINK "http://www.skyline-networks.com"http://www.skyline-networks.com This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom it is addressed. If you have received this email in error please notify the sender. Whilst every endeavour is taken to ensure that emails are free from viruses, no liability can be accepted for any damage arising from using this email. -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.394 / Virus Database: 268.8.1/354 - Release Date: 01/06/2006 ---------------------------------------------------------------------------- ---- > -- > WISPA Wireless List: email@example.com > > Subscribe/Unsubscribe: > http://lists.wispa.org/mailman/listinfo/wireless > > Archives: http://lists.wispa.org/pipermail/wireless/ > -- WISPA Wireless List: firstname.lastname@example.org Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/ -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.1.394 / Virus Database: 268.8.1/355 - Release Date: 02/06/2006 -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.394 / Virus Database: 268.8.1/355 - Release Date: 02/06/2006 -- WISPA Wireless List: email@example.com Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/