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| Thread ID: 27802 | 2002-12-03 06:55:00 | Cat or Coax? | Terry Porritt (14) | Press F1 |
| Post ID | Timestamp | Content | User | ||
| 102985 | 2002-12-03 06:55:00 | Just recently networked 2 Win98SE computers about 15 metres apart, using 10Mbp/s PCI cards and coaxial thin ethernet cable. I already had stacks of coax in the junk cable box, so it was a cheap installation. The question is, what if any are the technical/performance advantages of UTP cable over coax? ?:| |
Terry Porritt (14) | ||
| 102986 | 2002-12-03 07:02:00 | The biggest advantage is twisted pair is capable of full duplex, as two circuits are used. Typically in file copy situations between machines, there tend to be huge numbers of collisions, (slowing down the throughput) when there is only a single datapath - a la coax. (The same holds for a Hub (lots of collisions) as compared to a switch). |
wuppo (41) | ||
| 102987 | 2002-12-03 07:29:00 | Thanks wuppo, it's obvious when pointed out :) This link (grc.com) quoted by Tweake some time ago is good for setting secure bindings in the network configurations. |
Terry Porritt (14) | ||
| 102988 | 2002-12-03 07:52:00 | One of main benefits of UTP/STP over coax would be not having to have the ends of the cable terminated and the like. When it's just the 2/3 PCs that you use there wouldn't be much problem at all. | -=JM=- (16) | ||
| 102989 | 2002-12-04 01:55:00 | The collisions won't be a problem on Terry's network either; collisions are a result of lots of active users . I like coax . . . I have mostly coax, with some thick (real Ethernet :D) . I buy obsolete gear, so it took a while to get hubs and TP cables at cheap prices . So now I've got a bit of 10BaseT stuff now . (I've even got a "coax hub" -- a DEC repeater with one coax in, 6 out) . I'm now looking at 10MHz optical fibre stuff . |
Graham L (2) | ||
| 102990 | 2002-12-04 02:02:00 | >> The collisions won't be a problem on Terry's network either; collisions are a result of lots of active users. Interesting... the collision light on my hub is on almost fulltime, when I push large files from a WINXP machine to a 98SE machine. (no other active users) ;) |
wuppo (41) | ||
| 102991 | 2002-12-04 02:11:00 | Collisions are an indication that something is wrong. It is an overload situation which should never happen if the only traffic is one station sending a file to another. The only reverse traffic will be ACKs, and they are (a) very short, and (b) relatively infrequent if the receive window is reasonably sized. Try a crossover cable instead of a hub, and see if that goes faster. | Graham L (2) | ||
| 102992 | 2002-12-04 02:12:00 | I have a 10 Mbit Cat 5 connected hub, and almost never see any collisions when transferring data, or printing over the lan. | godfather (25) | ||
| 102993 | 2002-12-04 07:49:00 | Well the theory is all very good, but as I say, if I perform file copys between two PCs, I get bulk collisions. During the copy, network utilisation is around 80% according to XP, or 1MB/s according to NetStat (with the Acks at 17.5KB/sec). With two way traffic (even if one way is "only Acks"), I'm not surprised at collisions with 80% utilisation. |
wuppo (41) | ||
| 102994 | 2002-12-05 02:17:00 | This is not theory . If one computer is sending a file to another there should be no collisions . At the simplest level: after the connection is established, computer A sends a packet and waits for an ACK from the other computer . It sends another packet and waits for an ACK . This repeats until the file is sent, and there is a brief two way conversation while the connection is closed . Transfers can be speeded up by setting a recieve window so that ACKs are not sent for every packet, but only when needed (This is the usual setup) . TCP/IP is designed so that two host in a connection won't have collisions . More hosts can cause collisions, because they are not in a handshaking relationship . If you are getting collisions with no other network operations going on, something is wrong . . . Are you sure it's not the "data" light, rather than the "collision" one? Does the Windows have a utility which will show packet counts, collision counts, runts, resends, etc? I've often had 10 or more hosts running, with a lot of broadcasts, and different protocols (Netware, Appletalk, TCP/IP, MOP, BOOTP) . I don't have noticeable collision trouble . |
Graham L (2) | ||
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