Chapter 3 Message and Recovery Procedures

SPANTREE Messages

Error Message SPANTREE-3-BAD_PORTNUM_SIZE: Rejected an attempt to set the port number field size to [dec] bits (valid range is [dec] to [dec] bits).

Explanation An error occurred in the platform-specific code that caused it to request more or less bits than are possible. The spanning-tree port identifier is a 16-bit field, which is divided evenly between the port priority and port number, with each subfield being 8 bits. This allows the port number field to represent port numbers between 1 and 255. However, on systems with more than 255 ports, the size of port number portion of the port ID must be increased to support the number of ports. This is performed by the spanning-tree subsystem at system initialization because the maximum number of ports on a particular platform will not change. This error occurs because of an error in the platform-specific code, which causes it to request more or less bits than are possible. The first [dec] is the number of bits for the port number, and the second and third [dec] describe the valid range.

Recommended Action Copy the message exactly as it appears on the console or in the system log. Research and attempt to resolve the error by using the Output Interpreter. Enter the show version user EXEC command to gather data that might help identify the nature of the error. Use the Bug Toolkit to look for similar reported problems. If you still require assistance, open a case with the TAC, or contact your Cisco technical support representative, and provide the representative with the gathered information. For more information about these online tools and about contacting Cisco, see the “Error Message Traceback Reports” section on page 2-7.

Error Message SPANTREE-3-PORT_SELF_LOOPED: [chars] disabled.- received BPDU src mac ([enet]) same as that of interface.

Explanation A BPDU was received on the listed interface with a source MAC address that matches the one assigned to the listed interface. This means that a port might be looped back to itself, possibly because of an installed diagnostic cable. The interface will be administratively shut down. [chars] is the interface that received the BPDU, and [enet] is the source MAC address.

Recommended Action Check the interface configuration and any cable connected to the interface. When the problem is resolved, re-enable the interface by entering the no shutdown interface configuration command.

Error Message SPANTREE-3-PRESTD_NEIGH: pre-standard MST interaction not configured ([chars]).

Explanation The message means that the switch has received a prestandard multiple spanning-tree (MST) BPDU on an interface that is not configured to send prestandard MST BPDUs. The switch automatically adjusts its configuration on the interface and start sending prestandard BPDUs.

However, the switch does not automatically detect all prestandard neighbors, and we recommend that you configure the interface to send prestandard MST BPDUs by using the spanning-tree mst pre-standardinterface configuration command. This warning message only appears once. [chars] is the interface.

Recommended Action Use the spanning-tree mst pre-standardinterface configuration command on all the interfaces to which other switches running Cisco's prestandard MST version are connected. We recommend that you migrate all the switches in the network to the IEEE MST standard version.

 

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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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