3Com SuperStack II Switch 3000 10/100 User Manual page 126

C-4 A C: T -
PPENDIX ROUBLE
You have added the Switch 3000 10/100 to an
already busy network, and response times and
traffic levels have increased:
You may have added a group of users to one of the
Switch 3000 10/100 ports via a repeater or switch,
and not turned off Intelligent Flow Management
(IFM). Turn off IFM on any port that is connected to
multiple devices. Refer to
Ports" on page 4-12.
You have connected an endstation directly to
the Switch and the endstation fails to boot cor-
rectly:
The Switch has STP enabled, and the endstation is
booting before the STP initialization process is com-
plete. Specify that the port has Fast Start enabled,
and then reboot the endstation. For more informa-
tion about specifying Fast Start for a port, refer to
"Configuring the STP Parameters of Ports"
5-19.
The Switch keeps ageing out endstation entries
in the Switch Database (SDB):
The Switch has STP enabled, and STP is instructing
the Switch to age entries in the SDB faster because
topology changes are occurring in the network.
Reduce the number of topology changes by
1
enabling Fast Start for all ports which are directly
connected to an endstation; refer to
the STP Parameters of Ports"
SHOOTING
"Setting Up the Switch
on
"Configuring
on page 5-19.
Specify that the endstation entries are Non-ageing;
2
refer to
page
Consider disabling STP on the Switch, and using
3
resilient links to provide network resilience; refer to
"Enabling STP on the Switch"
"Setting Up Resilient Links"
You are trying to manage the Switch over a
network which has STP, and you are losing con-
tact with the management agent intermittently.
As shown in
Switch unit (Switch A) between your management
workstation and the Switch 3000 10/100 (Switch B).
You have configured more than one VLAN on both
Switch units, and there is a parallel STP path for
each VLAN between the Switch units.
When Switch B transmits BPDUs across a VLAN
page
other than VLAN 1, Switch A learns the MAC
address of Switch B through the port on that
VLAN. The managment agent of Switch B is only
accessible through VLAN 1, and so your manage-
ment workstation cannot communicate with Switch
B until it transmits BPDUs across VLAN 1. When that
occurs, Switch A learns the MAC address of Switch
B through the port on VLAN 1.
To avoid this situation, we recommend that you
connect the two SuperStack II Switch units using a
Virtual LAN Trunk (VLT). For more information
about VLTs, refer to
Between Switch Units"
"Setting Up the Switch Database (SDB)"
4-17.
on
on
Figure C-1, there is a SuperStack II
"Connecting Common VLANs
on page
on
page 5-16 and
page 4-20.
5-3.