Chapter 3 Message and Recovery Procedures

SPANTREE Messages

Error Message SPANTREE-2-BLOCK_PVID_PEER: Blocking [chars] on [chars]. Inconsistent peer vlan.

Explanation The spanning-tree port associated with the listed spanning-tree instance and interface will be held in the spanning-tree blocking state until the port VLAN ID (PVID) inconsistency is resolved. The listed spanning-tree instance is that of the native VLAN ID of the interface on the peer switch to which the listed interface is connected. The first [chars] is the interface, and the second [chars] is the spanning-tree instance.

Recommended Action Verify that the configuration of the native VLAN ID is consistent on the interfaces on each end of the IEEE 802.1Q trunk connection. When interface inconsistencies are corrected, spanning tree automatically unblocks the interfaces.

Error Message SPANTREE-2-CHNL_MISCFG: Detected loop due to etherchannel misconfiguration of [chars] [chars].

Note This message applies to Catalyst 3750, 3560, 2975, 2970, and 2960 switches.

Explanation A misconfiguration of a channel group has been detected. For example, the ports on one side of the EtherChannel either are not configured to be in the channel or failed to bundle into the channel, and the other side has successfully bundled the ports into the EtherChannel. The first [chars] is the port, and the second [chars] is the VLAN.

Recommended Action Identify the local ports by using the show interfaces status err-disabledprivileged EXEC command, and then check the EtherChannel configuration on the remote device by using the show etherchannel summary privileged EXEC command on the remote device. After the configuration is correct, enter the shutdown and then no shutdown interface configuration commands on the associated port-channel interfaces.

Error Message SPANTREE-2-LOOPGUARD_BLOCK: Loop guard blocking port [chars] on [chars].

Explanation The spanning-tree message age timer has expired because no BPDUs were received from the designated bridge. Because this condition could be caused by a unidirectional-link failure, the interface is put into the blocking state and marked as loopguard-inconsistent to prevent possible loops from being created. The first [chars] is the port name, and the second [chars] is the spanning-tree mode displayed in the show spanning-treeprivileged EXEC command.

Recommended Action Enter the show spanning-tree inconsistentports privileged EXEC command to review the list of interfaces with loopguard inconsistencies. Find out why devices connected to the listed ports are not sending BPDUs. One reason might be that they are not running the STP. If so, you should disable loop guard on the inconsistent interfaces by using the spanning-tree guard none interface configuration command or by starting the STP on the remote side of the links.

 

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

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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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