Troubleshooting guide

8-5
Cisco Broadband Local Integrated Services Solution Troubleshooting Guide
OL-5169-01
Chapter 8 Troubleshooting the Cisco Catalyst 6509
Copper
Make sure you have the correct cable for the type of connection you are making. Category 3 cable can
be used for 10MB UTP connections, but category 5 should be used for 10/100 connections.
A straight-through RJ-45 cable is used for end-stations, routers or servers to connect to a switch or hub.
An Ethernet crossover cable is used for switch to switch, or hub to switch connections. Below is the
pin-out for an Ethernet crossover cable. Maximum distances for Ethernet or Fast Ethernet copper wires
are 100 meters. A good general rule of thumb is that when crossing an OSI layer, like between a switch
and a router, use a straight-through cable; when connecting two devices in the same OSI layer, like
between two routers or two switches, use a cross over cable. For purposes of this rule only, treat a
workstation like a router.
The following two graphics show the pin-outs required for a switch-to-switch crossover cable.
Fiber
For fiber, make sure you have the correct cable for the distances involved and the type of fiber ports being
used (single mode, multi mode). Make sure the ports being connected together are both single mode, or
both multimode ports. Single mode fiber generally reaches 10 kilometers, multimode fiber can usually
reach 2 kilomemters, but there is the special case of 100BaseFX multimode used in half duplex mode
which can only go 400 meters.
For fiber connections, make sure the transmit lead of one port is connected to the receive lead of the other
port, and vice versa; transmit to transmit, receive to receive, will not work.
For gigabit connections, GBICs need to be matched on each side of the connection. There are different
types of GBICs depending on the cable and distances involved: Short wavelength (SX), long
wavelength/long haul (LX/LH), and extended distance (ZX).
For gigabit connections, GBICs need to be matched on each side of the connection. There are different
types of GBICs depending on the cable and distances involved: short wavelength (SX), long
wavelength/long haul (LX/LH), and extended distance (ZX). An SX GBIC needs to connect with an SX
GBIC; an SX GBIC will not link with an LX GBIC. Also, some gigabit connections require conditioning
cables depending on the lengths involved. Please refer to the GBIC installation notes.
If your gigabit link will not come up, check to make sure the flow control and port negotiation settings
are consistent on both sides of the link. There could be incompatibilities in the implementation of these
features if the switches being connected are from different vendors. If in doubt, turn these features off
on both switches.
Configuration Issues
Another cause of port connectivity issues is incorrect software configuration of the switch. If a port has
a solid orange light, that means that software inside the switch shut down the port, either by way of the
user interface or by internal processes.
Switch
3 TD+
6 TD–
1 RD+
2 RD–
Switch
3 TD+
6 TD–
1 RD+
2 RD–
H5579
H10581
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