On 20/06/2011, at 3:30 PM, Michael Hawkins wrote: > In the space of a few minutes speeds ranged from 3.4 mb/s download to 15.48 > (wireless), and 9.18 to 16.37 (ethernet, same modem). Uploads were all in > vicinity of 0.83 to 0.85. > > ADSL2+, Westnet, 77 St Georges Terrace > Perth.
Hi Michael, Nothing unusual about speed changes, because there may be a great many links in the chain between your Mac and the server it’s talking to, and any one of them could be the bottleneck. "For example: • Your Mac itself could have network configuration problems. • Your browser, or a plug-in, might be at fault • A particular process (such as an online backup program) could be monopolising your Internet bandwidth. • You could have a bad Ethernet cable. (Seriously!) • The Wi-Fi connection between your Mac and your AirPort base station or other wireless router might be too slow. • The broadband link to your ISP could be inherently slow, or the ISP could be experiencing temporary congestion. • The DNS servers that map domain names to IP addresses could be responding slowly, adding delays to each request you make. • The server on the other end—or any of the intervening routers, switches, hubs, gateways, and other equipment—might be too slow. When I Say “Slow...” Networking geeks are often quick to reprimand anyone who dares to use words like “slow,” “fast,” or “speed” when referring to a network, because signal speed per se—the movement of electrons through copper wire or photons through optical fiber—isn’t what most people are talking about. So what are we talking about? On the one hand, you have bandwidth, which is itself a metaphorical usage, but now generally refers to the capacity, or maximum possible data transfer rate, of a network segment as expressed in (tera-/ giga-/mega-/kilo-) bits per second. For example, your DSL connection may have a bandwidth of 8 Mbps (megabits per second), which means that, in theory, you could download a 1 MB file (1 megabyte = 8 megabits) in 1 second. However, a more important concept is throughput, which you can think of as the real-world data transfer rate (amount of data received per unit of time)—invariably a good bit lower than the theoretical bandwidth. Your so-called 8 Mbps connection may have throughput of only, say, 6 Mbps—and that can vary from moment to moment." Networking is a very interesting challenging project ;-) Cheers, Ronni 17" MacBook Pro 2.3GHz Quad-Core i7 “Thunderbolt" 2.3GHz / 8GB / 750GB @ 7200rpm HD OS X 10.6.7 Snow Leopard Windows 7 Ultimate (under sufferance) -- The WA Macintosh User Group Mailing List -- Archives - <http://www.wamug.org.au/mailinglist/archives.shtml> Guidelines - <http://www.wamug.org.au/mailinglist/guidelines.shtml> Unsubscribe - <mailto:[email protected]>
