C-14
Troubleshooting
Unusual Network Activity
Spanning-Tree Protocol (STP) and Fast-Uplink Problems
C a u t i o n
If you enable STP, it is recommended that you leave the remainder of the STP
parameter settings at their default values until you have had an opportunity
to evaluate STP performance in your network. Because incorrect STP settings
can adversely affect network performance, you should avoid making changes
without having a strong understanding of how STP operates. To learn the
details of STP operation, refer to the IEEE 802.1d standard.
Broadcast Storms Appearing in the Network.
This can occur when
there are physical loops (redundant links) in the topology.Where this exists,
you should enable STP on all bridging devices in the topology in order for the
loop to be detected.
STP Blocks a Link in a VLAN Even Though There Are No Redundant
Links in that VLAN.
In 802.1Q-compliant switches such as the Switch
4108GL, STP blocks redundant physical links even if they are in separate
VLANs. A solution is to use only one, multiple-VLAN (tagged) link between
the devices. Also, if ports are available, you can improve the bandwidth in this
situation by using a port trunk. See “Spanning Tree Operation with VLANs” on
page 11-30.
Fast-Uplink Troubleshooting.
Some of the problems that can result from
incorrect useage of Fast-Uplink STP include temporary loops and generation
of duplicate packets.
Problem sources can include:
■
Fast-Uplink is configured on a switch that is the STP root device.
■
Either the
Hello Time
or the
Max Age
setting (or both) is too long on one or
more switches. Return the
Hello Time
and Max Age settings to their default
values (2 seconds and 20 seconds, respectively, on a switch).
■
A "downlink" port is connected to a switch that is further away (in hop
count) from the root device than the switch port on which fast-uplink STP
is configured.
■
Two edge switches are directly linked to each other with a fast-uplink
(Mode =
Uplink
) connection.
■
Fast uplink is configured on both ends of a link.
■
A switch serving as a backup STP root switch has ports configured for
fast-uplink STP and has become the root device due to a failure in the
original root device.
Summary of Contents for ProCurve 4104GL
Page 2: ......
Page 26: ...xxiv Getting Started Need Only a Quick Start ...
Page 34: ...1 8 Selecting a Management Interface Advantages of Using HP TopTools for Hubs Switches ...
Page 50: ...2 16 Using the Menu Interface Where To Go From Here ...
Page 172: ...8 24 Time Protocols SNTP Messages in the Event Log ...
Page 240: ...10 30 Configuring for Network Management Applications CDP ...
Page 288: ...11 48 Port Based Virtual LANs VLANs and GVRP GVRP ...
Page 480: ...C 38 Troubleshooting Restoring a Flash Image ...
Page 486: ...D 6 MAC Address Management Determining MAC Addresses ...
Page 490: ......
Page 502: ...12 Index ...
Page 503: ......