Chapter 2: About the CSX200

This is done to replace the hidden local IP addresses from the sub network with one or more public InterNic assigned IP addresses that can be sent over the outside network on the WAN interfaces. Once the CSX200 is assigned at least one public IP address, over 250 IP clients can share this address simultaneously using NAT. This public IP address is assigned statically by the Internet Service Provider (ISP).

Frame Relay Protocol

Frame Relay can be defined as a “packet mode” service, organizing data into individually addressed units known as “frames”. Frame Relay eliminates Layer 3 processing. Only a few Layer 2 functions are used, such as checking for a valid, error free frame, but not requesting retransmission if an error is found. Frame Relay uses a variable length framing structure, which, depending on user data, can range from a few to more than a thousand characters.

A Frame Relay Network will often be depicted as a cloud, because the Frame Relay Network is not a single physical connection between one endpoint and another. Frame Relay Protocol is based on the concept of “virtual circuits” (VCs). VCs are two-way, software defined data paths between two ports that take the place of private lines in the network. There are two types of Frame Relay connections; Switched Virtual Circuits (SVCs), and Permanent Virtual Circuits (PVCs).

Permanent Virtual Circuits, or PVCs, are set up via a network management system, and initially defined as a connection between two sites, or endpoints. PVCs may be added as the demand arises for more bandwidth, alternate routing, or more sites, or endpoints. PVCs are fixed paths, not available on demand, or on a call-by-call basis. Although the actual path through the network may change from time to time, such as when automatic rerouting takes place, the beginning and end of the circuit will not change.

Switched Virtual Circuits, or SVCs, are available on a call-by-call basis using the SVC signaling protocol (Q.933). The network must quickly establish the connection, and allocate bandwidth based on the user’s request.

In a Frame Relay frame, user data packets are not changed in any way. A two-byte header is appended to the frame. Contained in this header is a 10-bit number called the Data Link Connection Identifier (DLCI). The DLCI is the “virtual circuit” number which corresponds to a particular destination. The DLCI allows data coming into a Frame Relay switch to be sent across the network using a three-step process: check the integrity of the frame and discard it if it is in error, look up the DLCI in a table and if not intended for this link, discard the frame. If the frame passes the previous tests, relay the frame toward its destination out the port specified in the table. If the frame passes the previous tests, relay the frame toward its destination out the port specified in the table.

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CSX200 Installation Guide

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Cabletron Systems CSX200 manual Frame Relay Protocol
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CSX200 specifications

Cabletron Systems was a leading developer of networking solutions, and its CSX400 and CSX200 series of high-performance switches represent some of the key innovations in the field of enterprise networking during their time. Both models were geared towards enhancing network reliability, efficiency, and speed, particularly in environments where heavy data traffic and complex networking demands were prevalent.

The CSX400, designed for larger enterprises, boasts a robust architecture capable of handling significant throughput. One of its standout features is its stackable design, allowing multiple switches to be interconnected and managed seamlessly as a single unit. This scalability provides organizations with the flexibility to expand their networks without significant infrastructure overhauls. The CSX400 supports various Ethernet standards, including 10/100 Ethernet and Gigabit Ethernet, positioning it to effectively manage both legacy and modern networking requirements.

In addition to its scalability, the CSX400 is distinguished by its advanced Layer 2 and Layer 3 routing capabilities. This dual-layer functionality enables efficient data handling and is instrumental in managing traffic between different network segments. Moreover, the switch incorporates features like VLAN (Virtual Local Area Network) support and Quality of Service (QoS) prioritization, allowing for enhanced performance of critical applications and streamlined bandwidth allocation.

On the other hand, the CSX200 series is tailored for smaller enterprises or branch offices needing a reliable yet efficient networking solution. Despite its compact design, the CSX200 is equipped with essential features that promote effective network management and security. It offers a simplified management interface, making it user-friendly for network administrators. The switch also provides essential access control measures, employing technologies like IEEE 802.1X for network access security.

Both the CSX400 and CSX200 prioritize performance through the incorporation of advanced switching technologies. They support features such as Spanning Tree Protocol (STP), enabling loop-free topologies and enhanced network resilience. These attributes are particularly crucial in dynamic networking environments where downtime can have significant repercussions on business operations.

Overall, Cabletron Systems' CSX400 and CSX200 series represent a blend of scalability, advanced routing capabilities, and user-friendly management, making them vital assets for organizations looking to optimize their network infrastructure during a period of rapid technological evolution. With their rich feature sets and unwavering performance, these switches helped pave the way for modern networking solutions that cater to diverse enterprise needs.
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