> 500 Meters?? It's 2500 meters. In one example of such a network, there can > be 5 segments, 4 repeaters (hubs), but only 3 segments can have end > systems. That's the infamous 5-4-3 "rule." It makes a lot of > assumptions. Really, the > size of the network depends on round-trip propagation delay for the > particular equipment, cables, and cable lengths.
Maybe I was wrong for thinking that. If my net was all 10 Base T, then with max 5 segments...500 meters. That's were I got that number from. Measuring the size of the collision domain is well under slot time. So I could technically extend the size of the network. One of the things I ran into was the formula to use to calculate the round trip delay. With the formula in your book I came up with 210 bit times round trip for 500 meter 4 hub network. But with the definitive guide's method I got 362 bit times. When I was going back and forth between books I think I got lost somewhere. For a 100 meter cable they suggest 11.3 bit times. While you suggest 5 one-way or 10 round trip...very close. But they start with a base value. Example First segment would be 26.55 bit times instead of 11.3. The base value is 15.25. 15.25+11.3=26.55 bit times for the first segment. I think I understand the theory behind slot time. It takes a station 51.2 micro seconds to transmit the smallest frame. So station a needs to be notified by any other station if a collision was to happen while it was still transmitting. So when the first bit of station a's preamble hits station z (at the other side of the network) rx pins while station z was transmitting, it's first bit hits the repeater. The repeater is going to use collision enforcement to make all stations including station a is aware of the collision. This must happen before station a finishes transmitting the smallest Ethernet frame. I think that is it. So should bit time be the time it takes to transmit the preamble and 512 bits? One more thing... A proper preamble should look like 10101010 or AA. I'm sure I read somewhere that a collision would appear with all 5's or C's. How would that be possible if as soon as the repeater detects a collision it sends out a jam signal out all its ports? Also a frame with a bad CRC is suspect of a collision. How? If you know where I could get more reading on this that would be great! Thanks for answering my questions! "We are what we repeatedly do. Excellence, then, is not an act, but a habit."--Aristotle Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=63659&t=63659 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
