Priscilla Oppenheimer wrote: > > Sim, CT (Chee Tong) wrote: > > > > Hi.. I have a friend staying in the hostel room which has a > > wall port > > (RJ45) link to the internet. As there are two persons (two > PC) > > staying in > > that room. So they bought a cable splitter. (one side with > > one female RJ45 > > jack and another side with two female RJ45 jack). So that two > > PCs can > > connect to internet at the same time, > > Are you sure it's Ethernet at your friend's hostel? Maybe it's > ISDN or something?? Someone will correct me if that's a dumb > statement. :-) > > If it was Ethernet, the only way it could have worked is if the > second pair happened to go to another switch port. You can't > turn one switch port into two simply by splitting the cable. > > As Chuck said, buy a hub. A 4-port hub is really cheap (at > least in the U.S!? ;-) > > Priscilla >
It's probably a hub in the hostel. I seem to recall occasionally using an RJ-45 splitter on my wall jack when we still used hubs. I had my PC in one port of the physical splitter and my laptop in the other. It was, in essence, a physical hub tied to an electrical one. I'm not saying this was a good thing to do for any length of time. But it did, on the surface, appear to work. What I never bothered to find out was whether or not the hub actually returned what I was transmitting on the receive pair. A lot of text books tell us that the NIC internally bridges its transmit to its receive so that it can detect a collision. I accept that. But I'm not sure if there is a reason why the hub wouldn't have repeated back on the same port that was being transmitted on? I wonder that, because if it had, it would have prevented collisions between the two machines tied to the physical splitter. Otherwise, I imagine I caused a lot of collisions between the two, since neither would know when the other was transmitting (I never realized how much background traffic an idle Windows machine can generate until I started doing some packet captures while reading your latest book). Now that I think about it, there is one good reason a hub wouldn't repeat back on the transmitting port: the propagation delay might make the comeback copy look like an entirely different transmission (i.e. a collision). I'm sure there are other good reasons too. Or maybe I dreamt the whole thing... Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=55756&t=55667 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
