From: Scott Morris (swm@emanon.com)
Date: Tue Apr 25 2006 - 11:12:19 GMT-3
The various CAT categories are not specific to what is used to transport
over them. The specifications have to do with the quality, makeup, size,
covering and twists in the cable itself able to sustain an
electrical/frequency over 'x' length. What they are used for is a separate
thing.
For short runs, you can run gigabit over Cat3 cable. You'll likely get more
retransmissions, because the cable isn't designed to maintain that level of
signal on it. For longer runs, there would be no way.
It's all about signal maintenance at the electrical/RF level, not how many
pairs you're using on it!
All of the RJ-45-based cables actually HAVE four pairs of wires. Whetherh
you use them or not is your own choice.
Cat5 is rated to 100MHz signal at length (100M). Cat5e is rated to 125MHz.
Cat6 (if memory serves) is rated to 250MHz. Cat 7 (again, if memory serves)
is rated to 350MHz.
The changes between categories are type of copper, type of shielding, number
of twists and things like that. The measurements are all about frequency
loss, insertion loss and the quality of both the cable and all connector
pieces involved (e.g. it doesn't do any good to have Cat7 cables and a Cat5
patch panel along the way!)
HTH,
Scott Morris, CCIE4 (R&S/ISP-Dial/Security/Service Provider) #4713, JNCIE
#153, CISSP, et al.
CCSI/JNCI
IPExpert CCIE Program Manager
IPExpert Sr. Technical Instructor
smorris@ipexpert.com
http://www.ipexpert.com
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of Tom
Young
Sent: Tuesday, April 25, 2006 9:39 AM
To: ccielab@groupstudy.com
Subject: cat5 for 1000baset
I understand the main difference between CAT5 and CAT5e
are:
1. CAT 5 - Uses two UTP pairs and supports 100 Mbps 2. CAT 5e - Uses four
UTP pairs and can transfer up to 1 Gbps.
I have taken some practice exams and there seem to be some conflicting
information about these two cables. One exam claims CAT 5 supports 1 Gbps??
Can someone verify??
Thanks.
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