HP 5500 SI Troubleshooting Manual page 21

Execute the display stp brief command to determine whether STP sets the state of the port to
discarding. When the port is in discarding state, it cannot forward traffic. HP recommends
disabling STP on the port, or configuring the port as an edge port if the port is connected to a
terminal device.
If the port belongs to an aggregation group, execute the display link-aggregation verbose
command to identify the port status. When the port is an Unselected port, it cannot forward
traffic. Find the reasons why the port is in Unselected state. For example, the attribute
configurations of the port are different from the configurations of the reference port.
Execute the display rrpp verbose command to determine whether one of the following has
occurred:
The port is down.
−
− RRPP has set the state of the port to blocked.
When the port is down or in blocked state, it cannot forward traffic.
If the port is in down state, determine whether the port is physically or administratively shut
−
down.
If the port is in blocked state, find the reasons. For example, the roles of the primary and
−
secondary port on the master node were reversed. Or, it might be that the broadcast storm
suppression mechanism blocked the port because SRPT failure occurred in a multi-homed
subring.
Execute the display smart-link group command to determine whether Smart Link sets the state
of the port to standby or down. When the port is in standby or down state, it cannot forward
traffic.
If the port is in standby state, set the port as the primary port.
If the port is in down state, the follow reasons might apply, and further troubleshooting is
required:
The uplink device is configured with Monitor link, and its uplink is down.
−
The link between the local port and its peer fails.
−
The local port is administratively shut down.
−
4. Examine the following configurations that might cause packet loss:
VLAN configuration—Execute the display this command in Ethernet interface view to display
whether the port is in the VLAN of the packets. If not, add the port to the VLAN.
Blackhole MAC address entries—Execute the display mac-address blackhole command to
display blackhole MAC address entries. If the packets are discarded because they match a
blackhole MAC address entry, delete the entry. To delete the blackhole MAC address entry,
execute the undo mac-address blackhole mac-address vlan vlan-id command.
Rate limit—Execute the display qos lr interface command to display the rate limit configuration
on the port. If rate limit is configured on the port, make sure the committed information rate (CIR)
and the committed burst size (CBS) are appropriate. To adjust the CIR and CBS values, execute
the qos lr outbound cir committed-information-rate [ cbs committed-burst-size ] command.
Storm suppression—Execute the display this command in Ethernet interface view to display the
configuration of storm suppression. Storm suppression includes broadcast suppression,
multicast suppression, and unknown unicast suppression. To adjust the suppression thresholds,
execute the broadcast-suppression, multicast-suppression, and unicast-suppression
commands, respectively.
21