I see latencies of ~3ms per radio hop using cisco gear.. These are real world links in high RF environments, but they also have awesome S/N ratios on the links with margins in excess of 40db. As you approach the noise floor, retries will increase, with 3ms being added per retry.
Here is a one hop ping: Reply from 10.12.75.8: bytes=32 time=4ms TTL=63 Reply from 10.12.75.8: bytes=32 time=4ms TTL=63 Reply from 10.12.75.8: bytes=32 time=4ms TTL=63 Reply from 10.12.75.8: bytes=32 time=4ms TTL=63 Here is a two hop ping: Reply from 10.12.75.6: bytes=32 time=5ms TTL=63 Reply from 10.12.75.6: bytes=32 time=5ms TTL=63 Reply from 10.12.75.6: bytes=32 time=5ms TTL=63 Reply from 10.12.75.6: bytes=32 time=5ms TTL=63 Here is a three hop ping: Reply from 10.12.75.81: bytes=32 time=9ms TTL=127 Reply from 10.12.75.81: bytes=32 time=9ms TTL=127 Reply from 10.12.75.81: bytes=32 time=9ms TTL=127 Reply from 10.12.75.81: bytes=32 time=9ms TTL=127 ----- Original Message ----- From: "Paul Cox" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Tuesday, February 18, 2003 5:38 PM Subject: [BAWUG] high latency on wireless links > Hi, > > Thinking the BAWUG group would have a great deal of experience in > deploying all kinds of links with 802.11 products, I've searched the > BAWUG archives looking for clues as to what kinds of latencies you have > encountered. > > The archives indicate that link layer retransmissions caused by faulty > equipment or a low S/N ratio could cause the latency on a particular > link to increase from a few milliseconds up to hundreds of milliseconds > and perhaps beyond a full second. There's also mention that links in a > heavily utilized mesh would also suffer from high latency. > > I'm looking for confirmation of these conclusions from those that have > first-hand experience with long-haul 802.11 links. I have been unable to > locate a list of the links in the bay area along with the latency > between nodes. If you could post your observations/data to the list it > would be quite useful. Are those running links over huge distances or > noisy environments seeing latencies in the hundreds of milliseconds or > more? > > Thanks, > > Paul Cox > > -- > general wireless list, a bawug thing <http://www.bawug.org/> > [un]subscribe: http://lists.bawug.org/mailman/listinfo/wireless > -- general wireless list, a bawug thing <http://www.bawug.org/> [un]subscribe: http://lists.bawug.org/mailman/listinfo/wireless
