802.1p Port Priority

Introduction

device, and to have it pause its transmission while the receiving device processes the frames already received. Flow control can be enabled or disabled on a port-by- port basis. Both devices must support the IEEE 802.3x standard for flow control to work.

The 9E531-24 supports the following two types of flow control:

•frame based 802.3x

•back pressure

Frame based 802.3x flow control is supported on all Ethernet ports operating in the full duplex mode.

Back pressure flow control is supported on all Ethernet ports operating in the standard mode of operation.

The IEEE 802.1p standard is used to assign a default priority to the frames received without priority information in their tag header, and to map prioritized frames to the appropriate transmit queues.

The default priority-to-queue mappings are shown in Table 1-1.This configuration can be changed by the administrator.

Table 1-1. Priority Queuing Configuration

Priority Indicator	Transmit Queue


7	3

6	3

5	2

4	2

3	1

2	0

1	0

0	1

Switching Options

The 9E531-24 provides IEEE Standard-based 802.1 switching or SecureFast Switching Virtual Network Services. In the 802.1 mode (the default mode of operation), the switch functions as an 802.1D switch. When VLANs are configured, it operates as an 802.1Q switch.

1-5

9F125-0, 9F122-12, 9F120-08 specifications

Cabletron Systems made significant contributions to the field of networking equipment, particularly with their product line that includes models like the 9F122-12, 9F120-08, and 9F125-08. These devices are renowned within the industry, particularly for their reliability and performance in enterprise networking environments.

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The Cabletron 9F125-08 is somewhat similar to the 9F120-08, also providing eight Ethernet ports. However, it incorporates additional features that improve its adaptability to various networking environments. This model supports a range of advanced protocols, allowing for integration with legacy systems while providing a pathway for future enhancements. The 9F125-08 is particularly valued for its capacity to handle mixed traffic types, including voice and data, making it an ideal choice for converged networks.

In terms of technology, Cabletron Systems emphasized modularity and scalability in its designs. These devices are built to accommodate future growth and changes in networking requirements. Each of these models supports various networking standards, ensuring compatibility with a wide range of existing infrastructure.

Overall, Cabletron Systems' 9F122-12, 9F120-08, and 9F125-08 are distinguished by their robust features, reliability, and adaptability. They are well-suited for businesses needing dependable networking solutions, and their legacy continues to influence networking technologies to this day.