Chapter 3 Message and Recovery Procedures

SPANTREE Messages

Error Message SPANTREE-2-ROOTGUARD_BLOCK: Root guard blocking port [chars] on [chars].

Explanation On the listed interface, a BPDU was received that advertises a superior spanning-tree root bridge (lower bridge ID, lower path cost, and so forth) than that in use. The interface is put into blocking state and marked as root-guard inconsistent to prevent a suboptimal spanning-tree topology from forming. The first [chars] is the port name, and the second [chars] is the spanning-tree mode displayed in the output of the show spanning-treeprivileged EXEC command.

Recommended Action Enter the show spanning-tree inconsistentports privileged EXEC command to review the list of interfaces with root-guard inconsistencies. Find out why devices connected to the listed ports are sending BPDUs with a superior root bridge, and take action to prevent more occurrences. When the inaccurate BPDUs have been stopped, the interfaces automatically recover and resume normal operation. Make sure that it is appropriate to have root guard enabled on the interface.

Error Message SPANTREE-2-ROOTGUARD_CONFIG_CHANGE: Root guard [chars] on port [chars] on [chars].

Explanation The spanning-tree root guard configuration for the listed interface has changed. If enabled, any BPDU received on this interface that advertises a superior spanning-tree root bridge (lower bridge ID, lower path cost, and so forth) to that already in use causes the interface to be put into the blocking state and marked as root-guard inconsistent. The first [chars] is the root-guard state (enable or disable), the second [chars] is the interface, and the third [chars] is the spanning-tree instance.

Recommended Action Verify that this is the desired configuration for the listed interface. Correct it if it is not the desired configuration; otherwise, no action is required.

Error Message SPANTREE-2-ROOTGUARD_UNBLOCK: Root guard unblocking port [chars] on [chars].

Explanation The listed interface is no longer receiving BPDUs advertising a superior root bridge (lower bridge ID, lower path cost, and so forth). The root-guard inconsistency is cleared for the interface, and the blocking state is removed from the interface. The first [chars] is the port name, and the second [chars] is the spanning-tree mode displayed in show spanning-treeprivileged EXEC command.

Recommended Action No action is required.

Error Message SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking [chars] on [chars]. Port consistency restored.

Explanation The port VLAN ID or port type inconsistencies have been resolved, and spanning tree will unblock the listed interface of the listed spanning-tree instance as appropriate. The first [chars] is the interface, and the second [chars] is the spanning-tree instance.

Recommended Action No action is required.

 

 

Catalyst 3750, 3560, 3550, 2975, 2970, and 2960 Switch System Message Guide

 

 

 

 

 

 

OL-8551-04

 

 

3-123

 

 

 

 

 

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3750 specifications

The Cisco Systems 3750 series is a family of enterprise-class stackable switches that were designed to provide high-performance networking solutions for organizations requiring robust management features, security, and scalability. Known for their reliability and advanced capabilities, the 3750 series is particularly aimed at accommodating the demands of LAN environments in organizations ranging from small businesses to large enterprises.

One of the defining features of the Cisco 3750 series is its StackWise technology. This innovative feature enables the stacking of up to nine switches together, allowing them to function as a single logical unit. This results in simplified management, higher redundancy, and increased scalability. The StackWise technology allows for seamless failover and enhanced bandwidth between the stacked switches.

In terms of performance, the 3750 series supports Layer 2 and Layer 3 switching, offering routing capabilities to handle both traditional and modern network demands. It is equipped with advanced Quality of Service (QoS) features, ensuring that critical applications such as voice and video are prioritized for optimal performance.

The Cisco 3750 also features extensive security capabilities. It incorporates features such as IEEE 802.1X authentication, DHCP snooping, and dynamic ARP inspection to protect against unauthorized access and various network attacks. These enhancements help maintain data integrity and secure communications across the network.

Another noteworthy characteristic of the 3750 series is its support for Power over Ethernet (PoE). PoE allows for the delivery of power over Ethernet cables to connected devices, such as IP phones and wireless access points, facilitating simpler installations and reducing the need for additional power outlets.

The Cisco 3750 series also provides a comprehensive set of management tools. With features like Cisco's Embedded Event Manager (EEM) and extensive SNMP support, network administrators can efficiently monitor and manage network performance, troubleshoot issues, and maintain high availability.

Additionally, the series is compatible with Cisco's IOS software, which provides a rich set of features, including advanced routing protocols, multicast support, and extensive security options, further enhancing the functionality and versatility of the switches.

Overall, the Cisco Systems 3750 series stands out for its stackable design, high-performance features, security capabilities, and management tools, making it a popular choice for organizations looking for dependable and scalable networking solutions.
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