- FAST ETHERNET SWITCH MODULE USER GUIDE 3H02-04, 3H08-04

Chapter 4: Monitoring
Page 4-2 FE Switch Module User Guide
• Spanning Tree - the port’s Spanning Tree state, which could be any
one of the following states:
• Blocking - The port isn’t currently the designated port to a
LAN and is not forwarding any packets. (This means another
port is providing the route to that LAN and since the Spanning
Tree protocol doesn’t allow simultaneous redundant paths, the
port is blocked. If the other port’s route to that LAN goes
down, this port would then start forwarding packets.)
• Listening - The port is listening for other bridges on the
network to determine if it should go to the forwarding or
blocking state.
• Learning - The port is listening for other bridges on the
network and making a table of addresses from packets that it
has received. Once the port goes to the forwarding state, it can
then use the address information it has learned.
• Forwarding - The port is the designated port for the LAN and
is forwarding packets and sending out bridge protocol
packets.
• Broken - The port is not forwarding packets. Reasons for a
broken status might include no cable connected, no link status,
the ring is not operational, or an NMS has disabled the port.
• Disabled - The port isn’t configured for Spanning Tree.
• Pkts Transmitted - number of packets transmitted from the port. This
includes any packets that might have experienced transmission errors.
(The port’s statistics are reset whenever the port is started.)
• Pkts Received - number of good packets received through the port.
Packets with reception errors are not included, nor are packets local to
that segment that are hardware filtered.
• Small Buffers - number of buffers currently assigned to the port (see
RX_Q Overflows below).
• RX_Q Overflows - number of incoming packets the port had to drop
because of a lack of buffers. After a reboot, the ATX tries to
automatically re-allocate the Small Buffers among the ports so that the
total number of RX_Q Overflows is minimized.