NB-30 Bridging

Changing Port Priority

To change the part of the Port Priority used in priority comparisons:

1.Highlight the port Priority field for the desired port, and enter the new priority identifier. Only valid hexadecimal numbers (0 to FF) are allowed in this field. The default is 80 hexadecimal.

2.Click on Set. The new port priority will be saved.

Changing Path Cost

To change the Path Cost:

1.Highlight the Path Cost field for the desired port, and type in a new value from 1 to 65535 decimal (default is 100 decimal).

2.Click on Set.

The new path cost will be applied to the port.

Filtering Database

The Filtering Database, which makes up the IEEE 802.1d Source Address Table, is used to determine which frames will be forwarded across the bridge from one network segment to another.

Transparent bridges like the NB-30 use the Filtering Database to determine a packetÕs route through the bridge. During initialization, the bridge copies the contents of its Permanent Database to the Filtering Database. Next, the bridge learns network addresses by entering the source address and port association of each received packet into the Filtering Database. When in the Forwarding state, the bridge examines each received packet, and then compares the destination address to the contents of the Filtering Database. If the destination address is located on the network from which the packet was received, the bridge Þlters (does not forward) the packet. If the destination address is located on a different network, the bridge forwards the packet to the appropriate network. If the destination address is not found in the Filtering Database, the bridge forwards the packet to all networks. To keep Filtering Database entries current, older entries are purged after a period of time, which is called the Dynamic Ageing Time.

The NB-30 Filtering Database consists of two separate databases: the Static and the LearnedDatabases.

The Static Database contains addresses that are entered by a network administrator. You add these addresses directly to the database while the bridge is powered up, or to the deviceÕs battery-backed RAM so that they are stored on shutdown until the next power-up.

The Learned Database consists of addresses that accumulate as part of the bridgeÕs learning process as it is up and running. These do not remain in the Source Address Table when the system is shut down. The Learned Database also contains the addresses that are in the Static Database upon start-up of the bridge.

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Filtering Database

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Cabletron Systems NB30 manual Filtering Database, Changing Port Priority, Changing Path Cost
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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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