Port Configuration; Vlans - Extreme Networks ExtremeWare XOS Guide Manual

Troubleshooting

Port Configuration

No link light on 10/100 Base port:
If patching from a hub or switch to another hub or switch, ensure that you are using a CAT5 cross-over
cable. This is a CAT5 cable that has pins 1&2 on one end connected to pins 3&6 on the other end.
Excessive RX CRC errors:
When a device that has auto-negotiation disabled is connected to an Extreme switch that has
auto-negotiation enabled, the Extreme switch links at the correct speed, but in half duplex mode. The
Extreme switch 10/100 physical interface uses a method called parallel detection to bring up the link.
Because the other network device is not participating in auto-negotiation (and does not advertise its
capabilities), parallel detection on the Extreme switch is only able to sense 10Mbps versus 100Mbps
speed, and not the duplex mode. Therefore, the switch establishes the link in half duplex mode using
the correct speed.
The only way to establish a full duplex link is to either force it at both sides, or run auto-negotiation on
both sides (using full duplex as an advertised capability, which is the default setting on the Extreme
switch).
NOTE
A mismatch of duplex mode between the Extreme switch and another network device will cause poor
network performance. Viewing statistics using the command on the Extreme
show ports rxerrors
switch may display a constant increment of CRC errors. This is characteristic of a duplex mismatch
between devices. This is NOT a problem with the Extreme switch.
Always verify that the Extreme switch and the network device match in configuration for speed and
duplex.
No link light on Gigabit fiber port:
Check to ensure that the transmit fiber goes to the receive fiber side of the other device, and vice-versa.
All gigabit fiber cables are of the cross-over type.
The Extreme switch has auto-negotiation set to on by default for gigabit ports. These ports need to be
set to auto off (using the command ) if you are connecting it to
configure port <port #> auto off
devices that do not support auto-negotiation.
Ensure that you are using multi-mode fiber (MMF) when using a 1000BASE-SX GBIC, and single mode
fiber (SMF) when using a 1000BASE-LX GBIC. 1000BASE-SX does not work with SMF. 1000BASE-LX
works with MMF, but requires the use of a mode conditioning patchcord (MCP).

VLANs

You cannot add a port to a VLAN:
If you attempt to add a port to a VLAN and get an error message similar to
localhost:7 # configure vlan marketing add port 1:1,1:2
Failed: Protocol conflict when adding untagged port 1:1,1:2. Either add this port as
tagged or assign another protocol to this VLAN.
238 ExtremeWare XOS 10.1 Concepts Guide