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You can first try disconnecting or shutting down the redundant trunks that are in forwarding state, causing the blocked trunks to switch to forwarding. You could also try doing a <i>no spanning tree vlan vlanid</i> to disable spanning for a particular vlan and then renenable. You could also try changing the root bridge for your STP instances. 
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You can first try disconnecting or shutting down the redundant trunks that are in forwarding state, causing the blocked trunks to switch to forwarding. You could also try doing a no spanning tree vlan vlanid to disable spanning for a particular vlan and then renenable. You could also try changing the root bridge for your STP instances.

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We're not running any actual STP stuff, it's in place for the loopback detection. &nbsp; Disabling/Enabling causes some packets, but not the high CPU situation.<br />
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Thanks for the help.
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We're not running any actual STP stuff, it's in place for the loopback detection.   Disabling/Enabling causes some packets, but not the high CPU situation.

Thanks for the help.

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We're seeing occasional high CPU utilization on our switches. &nbsp;High enough that our Cisco 2950's are not responding to telnet/snmp and the like. &nbsp;We're exploring the possibility that it's related to spanning-tree protocol, since we've got &nbsp;&gt;64 Vlans, which is over the 2950's max instance limit.<br />
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I'd like to test this theory by having the switches recalculate their STP information... I can't find a definitive answer on what it takes to make this happen.<br />
<br />
How can I force a STP broadcast storm?<br />
<br />
Thanks!
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We're seeing occasional high CPU utilization on our switches.  High enough that our Cisco 2950's are not responding to telnet/snmp and the like.  We're exploring the possibility that it's related to spanning-tree protocol, since we've got  >64 Vlans, which is over the 2950's max instance limit.

I'd like to test this theory by having the switches recalculate their STP information... I can't find a definitive answer on what it takes to make this happen.

How can I force a STP broadcast storm?

Thanks!

Force Recalculation of Spanning Tree Protocol

A switch is a device that filters and forwards packets of data between LAN segments. Switches operate at the data link layer or the network layer of the Open Systems Interconnection (OSI) Reference Model and therefore support any packet protocol. LANs that use switches to join segments are called switched LANs or, in the case of Ethernet networks, switched Ethernet LANs. A hub is a connection point for devices in a network. Hubs are commonly used to connect segments of a LAN. A hub contains multiple ports; when a packet arrives at one port, it is copied to the other ports so that all segments of the LAN can see all packets.

Switches / Hubs

Network analysis is the process of identifying and remediating the processes and systems within a network, including performance, connectivity and security. The process is performed through the use of tools developed for monitoring and analyzing network activity. Network problems that involve finding an optimal way of doing something are studied under the name combinatorial optimization. Examples include network flow, shortest path problem, transport problem, transshipment problem, location problem, matching problem, assignment problem, packing problem, routing problem, Critical Path Analysis and PERT (Program Evaluation & Review Technique).

Network Analysis

Network Operations includes asset management, help-desk supervision, security and user policies, infrastructure administration and anything else that affects the operation of your network. Discussions will include those of best practices in platforms, configurations, performance, security and accounting.