BC In/Out, Be In/Out | Cabletron Systems 1800, FRX4000, FRX6000

Frame Relay Status and Conﬁguration

TIP

above the deÞned CIR can be marked as discard eligible (DE); frames with the DE bit set are considered to be excess data, and will be discarded if the network becomes congested.

If congestion occurs on the selected DLCI while throughput is greater than the CIR, and the Outgoing Rate Control parameter (settable via the Frame Relay Port ConÞguration window, described beginning on page 5-2) is set to Yes, the throughput will immediately drop to the CIR level.

BC (In/Out)

Use this Þeld to enter the Committed Burst Size (BC) assigned to the selected DLCI by your frame relay provider. The committed burst size deÞnes the maximum amount of data (in bits) that the network agrees to transfer, under normal conditions, during a time interval TC. TC (also called the Òbandwidth intervalÓ) is calculated by dividing the committed burst size (BC) by the committed information rate (CIR); it deÞnes the time interval during which the user can send only BC amount of data and BE excess data (see deÞnition of BE, below). Any trafÞc which exceeds this burst rate will be marked discard eligible (DE), and discarded if the network becomes too congested. While sustained BC trafÞc rates are not guaranteed, BC trafÞc has a higher delivery probability than BE (described below).

You can view the amount of trafÞc on the selected physical interface which is marked as discard eligible via the Frame Relay Congestion Stats window, described beginning on page 5-22.

BE (In/Out)

Use this Þeld to enter the Excess Burst Size (BE) assigned to the selected DLCI by your frame relay provider. The excess burst size deÞnes the amount of data (in bits) over the committed burst size (BC) that the network will attempt to transfer during the time interval TC (remember, TC is calculated by dividing the committed burst size (BC) by the committed information rate (CIR)). Any data exceeding this value will be buffered in the FRX device. Note that DE frames are considered to be BE excess data.

BECN

The BECN Recovery Count provides a means for controlling the rate of return to maximum trafÞc ßow after it has been reduced due to congestion. If a packet is received on the selected DLCI with the BECN (backward explicit congestion notiÞcation) bit set, the conÞgured BE Out value will be ignored and the effective value will become zero (limiting trafÞc ßow to the value conÞgured for BC Out). This limit will remain in place until the DLCI receives a speciÞed number of sequential packets without the BECN bit set: the number speciÞed by the BECN Recovery Count. Each time the conÞgured number of sequential packets is received, the effective BE Out will be increased by one-eighth of the conÞgured value.

5-10	Conﬁguring Frame Relay Ports

1800, FRX4000, FRX6000 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.