NB-30 Bridging

About Transparent Bridging

Transparent bridges are most common in Ethernet networks. Individual Transparent bridges monitor packet trafÞc on attached network segments to learn where end stations reside in relation to each segment by mapping the Source Address of each received frame to the port (and segment) it was detected on. This information gets stored in the bridgeÕs Filtering Database.

When in the Forwarding state, the bridge compares a packetÕs destination address to the information in the Filtering Database to determine if the packet should be forwarded to another network segment or Þltered (i.e., not forwarded). A bridge Þlters a packet if it determines that the packetÕs destination address exists on the same side of the bridge as the source address.

If two or more bridges are connected to the same Ethernet LAN segmentÑplaced in parallelÑonly a single bridge must be allowed to forward data frames onto that segment. If two or more bridges were forwarding data frames onto the same Ethernet segment, the network would soon be ßooded.

With a data loop in the topology, bridges would erroneously associate a single source address with multiple bridge ports, and keep proliferating data by forwarding packets in response to the ever-changing (but incorrect) information stored in their Filtering Database.

To avoid such data storms, Transparent bridges communicate with one another on the network by exchanging Bridge Protocol Data Units (BPDUs) to determine the network topology and collectively implement a Spanning Tree Algorithm (STA) that selects a controlling bridge for each LAN segment; this ensures that only a single data route exists between any two end stations and that topology information remains current.

Viewing and Managing Bridging Interfaces

With SPECTRUM Element Manager, you can view and manage each bridging interface supported by your NB-30. You manage your bridge by using the following windows:

¥The Bridge Status window provides you with basic information about the current status of the NB-30Õs bridging interfaces, allows you to conÞgure each interface, and lets you enable or disable bridging across the bridge. The Bridge Status window also lets you access further windows to conÞgure bridging at the NB-30 (see Bridge Status, page 3-3).

¥Bridge StatisticsÑincluding the Performance Graph, Bridge Summary Statistics and the Ethernet and Remote Port Statustics windowsÑgraphically display the trafÞc passing between your bridged networks, and let you compare and contrast trafÞc processed by each interface (see Bridge Statistics, page 3-9).

3-2

Bridging Basics

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Cabletron Systems NB30 manual About Transparent Bridging, Viewing and Managing Bridging Interfaces
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NB30 specifications

Cabletron Systems NB30 is a noteworthy networking device that emerged in the mid-1990s as a critical component for businesses looking to enhance their local area network (LAN) capabilities. Designed primarily for the burgeoning demand of network speed and reliability, the NB30 served as a bridge in networking technology, offering organizations a robust solution to keep up with the advancing digital landscape.

One of the main features of the Cabletron NB30 is its ability to support both Ethernet and Token Ring protocols. This dual compatibility made it an attractive choice for enterprises that were transitioning from older networking systems to newer infrastructures. By accommodating both technologies, the NB30 enabled smoother migrations without necessitating a complete overhaul of existing networking components.

Another significant characteristic of the NB30 is its modular architecture. This design allowed organizations to customize their networking setup according to specific needs and preferences. Users could add or replace modules to enhance functionality, from extra ports to support additional devices or advanced features like network management tools, ensuring that their systems could grow and evolve in tandem with their business requirements.

The NB30 also utilized a stackable design, which facilitated scalability. Organizations could easily connect multiple NB30 units to increase their network capacity and performance. This stacking capability was a significant advantage as it allowed for efficient use of space and resources while providing a path for future growth.

In terms of performance, the Cabletron NB30 boasted a switching capacity that enabled quick data transfer rates, reducing latency and improving overall network responsiveness. This speed was crucial during a period when businesses were increasingly reliant on real-time data exchange and communication.

Additionally, the NB30 incorporated advanced network management features, enabling administrators to monitor traffic, diagnose issues, and implement changes with ease. This level of control was essential for maintaining network health, ensuring that businesses remained operational without unnecessary downtimes.

Overall, Cabletron Systems NB30 played a pivotal role in the evolution of networking technology. Its combination of protocol flexibility, modular design, scalability, and robust performance made it a popular choice for businesses looking to create efficient, dependable networks in an era of rapid technological advancement. The NB30's legacy continues to influence modern networking solutions, demonstrating the importance of adaptability and performance in the ever-changing digital world.
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