BPDU frames will be received or transmitted, to allow the port to get its status into the spanning tree algorithm. The port will leave this state when the Bridge Forward Delay timer (see page 16-4) expires. If the port is selected as Root or Designated port, it will enter Forwarding state. If the port is not selected as Root or Designated port, it will enter Blocking state.

A Root port is the one selected by the spanning tree algorithm as the port used to reach the root bridge (which is the least-cost bridge in a link). A Designated port is the port that connects to the least-cost path to the root bridge.

◆Learning – BPDUs ("Hello" messages) are being sent between bridges, and the spanning tree algorithm is being updated. The port will leave this state when the Bridge Forward Delay timer (see page 16-4) expires. If the port is selected as Root or Designated port, it will enter Forwarding state. If the port is not selected as Root or Designated port, it will enter Blocking state.

◆Forwarding – the Bridge port is participating in bridging of frames, as well as ongoing learning and updating of the spanning tree algorithm. If the algorithm redesignates the port as non-root or non-designated, the port might enter Blocking state.

◆Blocking – the Bridge port has not been selected as Root or Designated, and is transitioning to the Listening state.

●Rcv/Xmit – are the cumulative bytes received/transm itted on the Bridge port.

Bridge Forwarding Table

The Bridge Forwarding Table is used to match MAC addresses with Bridge ports on which to forward frames. If an address is not found in the table, the frame will be for- warded out all Bridge ports except those configured for native LLC-2.

All MAC addresses are in non-canonical (Token Ring) format.

As a frame is received, its source and destination MAC addresses will be added (if not already there) to the table. (If received from a Token Ring, the addresses will be bit- swapped [described under "Host MAC Address" on page 9-22] when added to the table.) The SmartSwitch 1800 software contains a set of reserved MAC addresses that are considered "static," and will always be in the table. The remaining entries are con- sidered "dynamic," and will remain in the table for the time period configured as the Bridge Aging Timer in Bridge Node Defaults.

Press [B] at the Bridge Status Displays Menu to display a forwarding table for all MAC addresses received on Bridge ports in the node.

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Cabletron Systems 1800 manual Bridge Forwarding Table, All MAC addresses are in non-canonical Token Ring format
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1800 specifications

Cabletron Systems, a leading player in network management and telecommunications solutions during the late 20th century, introduced several innovative products that played a crucial role in shaping enterprise networking. Among these were the Cabletron FRX6000, FRX4000, and the FRX1800, which delivered advanced features aimed at enhancing network performance, security, and scalability.

The Cabletron FRX6000 was designed as a robust multi-layer switch, ideal for large-scale enterprise environments. It supported extensive routing capabilities, allowing organizations to manage traffic efficiently even under heavy loads. The FRX6000 boasted high throughput rates and low latency, making it suitable for demanding applications. With support for various network protocols, including IP, IPX, and AppleTalk, its adaptability made it a versatile choice for diverse networking needs. Moreover, security features like VLAN support and Access Control Lists (ACLs) provided enhanced protection against potential threats.

Moving to the FRX4000, this model offered a balance between performance and cost-effectiveness. The FRX4000 maintained many of the essential features of its larger counterpart while catering to medium-sized enterprises. It provided Layer 3 routing and could handle multiple simultaneous connections, ensuring seamless communication across departments. The modular design allowed for easy upgrades, enabling businesses to expand their network infrastructure without significant overhauls. This made the FRX4000 an attractive option for organizations looking to optimize their network investments.

Lastly, the FRX1800, designed for small to medium businesses, focused on simplicity and ease of use while still incorporating powerful network management capabilities. Its user-friendly interface made it accessible for organizations lacking extensive IT resources. The FRX1800 provided essential functionalities such as Integrated Layer 2 switching and routing, network monitoring, and basic security features, ensuring that even smaller companies could maintain efficient, reliable networking without overwhelming complexity.

All three models utilized advanced technologies, including a high bandwidth backbone and state-of-the-art switching architecture, to enable fast and reliable data transfer. They also supported Quality of Service (QoS) mechanisms, allowing businesses to prioritize critical applications and ensure consistent performance across the network.

In summary, the Cabletron FRX6000, FRX4000, and FRX1800 were pivotal in enhancing network capabilities, providing organizations with scalable, secure, and high-performance options tailored to their specific needs.
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