The default value of 2000 ms allows avoidance of unnecessary retransmission of frames that have merely been delayed.

Maximum Retransmissions

is the maximum number of times the node will attempt to send an I-frame after a Retransmission Period expiration. A larger value for this parameter increases the prob- ability of an eventual successful transmission, but a smaller value permits faster detection of a permanent error condition.

Maximum Bytes per Frame

is the maximum frame size that will be transmitted on the port.

Generate Clock

specifies whether the port will generate the clock necessary to synchronize traffic over the link. If the port is a physical DCE (determined by the port's I/O cable interface), specify Y, since the physical DCE generates clock. If the port is DTE, specify N.

Rcv Clock (TT) from DTE

allows the clock to be looped back from the DTE using the TT (Terminal Timing) signal, which can be helpful on high-speed lines. Generally, if the local interface is physical DCE and the line speed is above 256 Kbps, this parameter should be set to Y. (Make sure the remote DTE is configured to provide the terminal timing.)

EBCDIC

stands for "Extended Binary Coded Decimal Interchange Code." Specifying Y requires that all devices on a line use the same character set for successive session polls. It is activated after a session is over; i.e., an EOT (End of Transmission) is suc- cessfully transmitted down the line. On expiry, a General Poll is transmitted, except under certain special conditions. The timer is deactivated at Link Down.

Transparent Text Supported

causes (if Y) all characters transmitted, including control character sequences, to be treated as data. This is useful for transmitting binary data, machine language computer programs, etc., without special coding.

Data-link control character sequences transmitted during transparent mode must be preceded by character 1/0 (DLE) in order to be recognized as control characters.

Ack

specifies which methods of acknowledgement will be used:

A = ETB:loc, ETX:end – local acknowledgement of transmission blocks, end-to-end acknowledgement of text.

B = ETB:end, ETX:end – end-to-end acknowledgement of transmission blocks and text .

C = ETB:loc, ETX:loc – local acknowledgement of transmission blocks and text.

ETB = End of transmission block, ETX = End of text.

Configuring BSC Batch

11-5

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Cabletron Systems 1800 manual ETB = End of transmission block, ETX = End of text
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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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