Network+ Questions

Altin

Hi

Started studying for the Network+ Exam recently and have a few questions. Hope this is the right place to post them.

In 10Base5 networks, why exactly do the transceivers have to be placed at the 2.5 m intervals? 10Base2 only requires they be a minimum of a half metre apart, but not at specific points, so why so in 10Base5? Also how do the transceivers attach themselves to the bus cable? I can understand what happens in 10Base2 alright, but would like a little more detail on the 10Base5 model.

Also the book I have mentions that repeaters are useful for keeping a network segment working if another segment suffers a cable break. But what I dont understand is that if the repeater simply repeats what it receives onto the other network segments ordinarily, how or why does it not do this when it starts to receive interference signals from the line breakage?

Thanks for your help

captobvious

From wikipedia:

10BASE5 - Wikipedia, the free encyclopedia

The maximum practical number of nodes that can be connected to a 10BASE5 segment is limited to 100 and transceivers may be installed only at precise 2.5-metre intervals. This distance was chosen to not correspond to the wavelength of the signal; this ensures that the reflections from multiple taps are not in phase.[2] These suitable points are marked on the cable with black bands. The cable must be one linear run; T-connections are not allowed. A 50-ohm resistive terminator is required at each end of the cable.

Transceivers can be connected to cable segments with N connectors, or via a vampire tap, which allows new nodes to be added while existing connections are live. A vampire tap clamps onto the cable, forcing a spike to pierce through the outer shielding to contact the inner conductor while other spikes bite into the outer braided shield. Care must be taken to keep the outer shield from touching the spike; installation kits include a "coring tool" to drill through the outer layers and a "braid pick" to clear stray pieces of the outer shield.

The transceivers connect to nodes using a connector called an Attachment Unit Interface (AUI), a 15-pin, two-row D-style connector, but using a sliding clip instead of screws for cable restraint. A multi-wire cable carries the connection between the transceiver and the node.

2. ^ IEEE Standard 802.3-1985, IEEE, pp. 121, ISBN 0-471-82749-5

BigLou

I thought 10Base2 an 10Base5 questions are no longer on the test?

ElvisG

They are listed in the old and new objective.

TravR1

Coaxial can definitely still jump out and surprise you on test day. Don't let yourself get burned by them.