Cisco Catalyst 3550 Installation Manual page 42

Front-Panel Description
Table 1-8 Meaning of LED Colors in Different Modes on the Switch
Port Mode LED Color
STATUS Off
(port status)
Solid green
Flashing green Activity. Port is transmitting or receiving data.
Alternating
green-amber
Solid amber
Flashing amber Port is blocked by STP and is transmitting or receiving packets.
UTIL Green
(utilization)
Amber
DUPLX Off
(duplex)
Green
SPEED 10/100 and 10/100/1000 ports
Off
Green
Flashing green Port is operating at 1000 Mbps.
GBIC ports
Off
Flashing green Port is operating at 1000 Mbps.
Catalyst 3550 Multilayer Switch Hardware Installation Guide
1-18
Meaning
No link, or port was administratively shut down.
Link present.
Link fault. Error frames can affect connectivity, and errors such as
excessive collisions, CRC errors, and alignment and jabber errors
are monitored for a link-fault indication.
Port is blocked by Spanning Tree Protocol (STP) and is not
forwarding data.
Note After a port is reconfigured, the port LED can remain amber
for up to 30 seconds as STP checks the switch for possible
loops.
The port LEDs display backplane utilization on a logarithmic scale.
See Figure 1-12 and Figure 1-13
Catalyst 3550-12T and 3550-12G switches. See
Figure 1-15 for details on the Catalyst 3550-24 and 3550-48
switches.
The peak total backplane utilization over the last 24 hours.
Port is operating in half duplex.
Port is operating in full duplex.
Port is operating at 10 Mbps.
Port is operating at 100 Mbps.
Port is not operating.
Chapter 1 Product Overview
for details on the
Figure 1-14 and
78-11358-03