I agree. Uplink doesn't have a technical meaning. It gets used in many ways. I thought he was talking about Cisco's fancy Uplink Fast feature at first. Its most common usage is when talking about hub ports, as you mentioned below. Some switches have uplink ports too. Cisco switch uplink ports are often fiber-optic ports, and that's a whole different story that I won't get into.
One comment below. Michael Williams wrote: > > IMHO, uplink just means "connection". Nothing special. If we > use the term to mean anything, usually we use it in the context > of data flow (i.e. we would call the port on a closet switch > that connects to the distribution layer switch the "uplink", > but also if talking about traffic moving from the core outward, > we may call the port on the core switch/router to the > distribution switch an "uplink" port). This is more of a > day-to-day, casual conversation usage for me and my co-workers, > so it may not apply to many others. > > Back in the day, when using hubs, many times they would have an > "uplink" port, which was essentially a crossed port. Usually an uplink port is not crossed, I thought. A hub or switch must do a cross-over internally at each normal (network) port to make sure TX gets to RX and RX gets to TX. An uplink port is not crossed, however. You need to make sure that the crossover happens an odd number of times, one time being the optimal. That way receivers can talk to transmitters and transmitters can talk to receivers. So, a PC (which does no cross-over) sends to a hub with a straight-though cable (which does not cross-over). The signal ends up at the hub port where the crossover occurs. The PC's TX becomes the hub's RX so the hub can receive what the PC sent. If you connect two hubs back-to-back, then the cross-over happens twice. This is bad. So you use a cross-over cable. That way the cross-over happens 3 times (an odd number of times), so you're OK. And that's where the uplink ports on hubs and switches comes in. An uplink port doesn't do the cross-over. That way you can connect hubs or switches back-to-back, like you said. You could connect an uplink port on one hub to a non-uplink port on another hub using a straight-through cable. The cross-over happens just once at the non-uplink port. Or you could connect uplink-to-uplink, but then you have to use a cross-over cable. If that's wrong, just let me know! I haven't had my caffeine yet. _______________________________ Priscilla Oppenheimer www.troubleshootingnetworks.com www.priscilla.com (i.e. you > could connect the "uplink" port on one hub using a "regular" > ethernet cable to any "non-uplink" port on another hub.) So in > that sense, uplink really just means crossed. > > With switches, the point is moot. I've not seen many switches > if any (especially Cisco switches) with an "uplink" port (not > saying they don't exist, just that I haven't seen one). So > basically with switches, just use a crossover cable and connect > any port on switch S to any port on switch R and you're done! > > Mike W. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=61859&t=61852 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
