I'm using NStreme on both the AP and client devices. Would these figures not reflect the same thing in an NStreme environment and if not why not?
-----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of David Sovereen Sent: 03 June 2006 15:49 To: wireless@wispa.org Subject: Re: [WISPA] Mikrotik Virtual AP Following up to my own post... Short of removing the RF interference (relocate CPE, cut down a branch, a tree, etc), about all you can do is increase the gain of the client's antenna. As an alternative to looking at the jitter and packet loss at the IP layer, these numbers will help you quantify whether or not you are improving the customer's connection (and as a result, the performance of all customers on the same AP). If you take TX Frames and divide into TX Hw Frames, subtract 1, and ignore the negative sign or multiply by -1 (i.e. ((TX Frames / TX Hw Frames) - 1) * -1), you will get the percentage of retransmits. This number should be as low as possible. High retransmit rates affect the service and performance of all customers on an AP. Dave 989-837-3790 x 151 989-837-3780 fax [EMAIL PROTECTED] www.mercury.net 129 Ashman St, Midland, MI 48640 ----- Original Message ----- From: "David Sovereen" <[EMAIL PROTECTED]> To: "WISPA General List" <wireless@wispa.org> Sent: Saturday, June 03, 2006 10:29 AM Subject: Re: [WISPA] Mikrotik Virtual AP > There isn't much you can do; we're not given controls over settings at that > low layer. > > You can quantify the number of retransmits on a per-client basis in Mikrotik > APs operating in 802.11a/b/g mode (but not Nstreme) by going to Wireless -> > Registration, double-clicking the client, and going to the Statistics tab. > > Compare TX Frames with TX Hw Frames. TX Frames is the number of packets > sent from the upper layer (typically IP or PPPoE, but could be other > protocols) to the RF/wireless ethernet layer. TX Hw Frames is the number of > packets sent over the air, including re-transmits. In a perfect > environment, these numbers will be equal, i.e. 10,000 IP packets = 10,000 > RF/wireless ethernet frames. If a 10 packets needed to be retransmitted, > then the example I'm using would show 10,010 TX Hw Frames. > > Retransmissions from the client to the AP can only be seen on the client > side. If the client is running Mikrotik, you will find the information in > the same place looking at the same TX statistics. Not all equipment > provides this information. > > 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'" <wireless@wispa.org> > Sent: Saturday, June 03, 2006 10:11 AM > Subject: RE: [WISPA] Mikrotik Virtual AP > > > 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'" <wireless@wispa.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. 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