Appendix B. Flow Control

Flow control is a mechanism which allows you to protect the switch from overload conditions and to keep additional traffic off the network when excessive congestion will result.

Flow Control for Half- and Full-Duplex Applications

Each port of the switch has a transmit queue which buffers frames to be sent out on that port. In this example, large amounts of data are being sent from Workstation A (connected to port X) and other ports on the switch to Workstation B (connected to port Y).The queue on port Y starts filling up with data until it reaches a determined threshold. The packet which causes the threshold to be exceeded triggers the flow- control function on the port from which the packet entered the switch, in this case port X.

Since port X is configured with flow control set to Enabled, the switch responds by initiating a pause frame (full-duplex applications) or back-pressure mechanism (half-duplex applications). The pause frame causes Workstation A to stop sending packets. After a certain amount of time has elapsed, determined by a value in the pause frame, Workstation A will resume sending data. Similarly, the back-pressure mechanism forces Workstation A to stop sending packets by inducing collisions on port X.

The pause-frame flow-control mechanism supported by the VH-2402-L3 switch conforms with the IEEE 802.3x specification for full-duplex flow control.

For the full-duplex pause-frame mechanism to work, the device connected to the switch port must also support IEEE 802.3x flow control.

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Enterasys Networks VH-2402-L3 manual Appendix B. Flow Control, Flow Control for Half- and Full-Duplex Applications
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VH-2402-L3 specifications

Enterasys Networks VH-2402-L3 is a high-performance Layer 3 switch that blends advanced networking features with robust security measures, catering to the demanding needs of modern enterprise environments. This device is designed to support complex networking requirements and deliver unparalleled efficiency, making it a top choice among IT professionals.

One of the main features of the VH-2402-L3 is its impressive port density. It typically includes 24 Gigabit Ethernet ports and can support both copper and fiber connections. This flexibility allows organizations to seamlessly integrate the switch into existing infrastructures without needing extensive upgrades. Additionally, the VH-2402-L3 is equipped with 2 SFP (Small Form-factor Pluggable) slots, which enable the use of various transceiver modules for scalable network expansion.

The VH-2402-L3 leverages advanced Layer 3 routing protocols to ensure optimal data flow across the network. With support for dynamic routing protocols such as RIP, OSPF, and BGP, the switch effectively manages traffic between different subnets, improving overall network efficiency. This capability is essential for enterprises that require reliable inter-VLAN routing and seamless connectivity across multiple network segments.

Embedded security features are another standout characteristic of the VH-2402-L3. It includes support for Access Control Lists (ACLs), VLANs, and IEEE 802.1X authentication, which collectively bolster the security posture of the network. These features help mitigate unauthorized access and ensure that sensitive data remains protected. Additionally, the switch’s built-in support for network segmentation allows IT teams to isolate critical applications and services, further enhancing security.

The VH-2402-L3 also emphasizes ease of management with its user-friendly interface and comprehensive management options. With SNMP (Simple Network Management Protocol), RMON (Remote Monitoring), and a web-based GUI, network administrators can monitor and manage switch performance, configuration, and security with minimal effort.

In conclusion, Enterasys Networks VH-2402-L3 is engineered to meet the challenges of contemporary networking environments. Its blend of high port density, advanced routing capabilities, robust security protocols, and user-friendly management tools makes it a highly reliable solution for organizations seeking to enhance their network infrastructure. Whether for enterprise-level operations or smaller businesses, this switch is designed to provide dynamic performance and ease of use, ensuring that organizations can confidently navigate the complexities of the digital landscape.
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