FDDI Applications

Ethernet 802.2

The Ethernet 802.2 frame format is the IEEE 802.3 formalization of the original Ethernet frame format. This frame format is similar to the Ethernet II frame format, except that the two byte Type Þeld is eliminated and replaced with a two byte Length Þeld, and an 802.2 LLC header is encapsulated within the 802.3 frame. This LLC header contains the destination and source addressing information for the LLC frame (DSAP and SSAP), and a one byte Control Þeld (the LSAP Ð or LLC Service Access Point value) which provides the frameÕs protocol ID. Ethernet 802.2 packets are differentiated from Ethernet II packets because the Length Þeld will always have a decimal value of 1500 or less (since the data Þeld in Ethernet frames cannot be greater than 1500 bytes), and the Ethernet II Type Þeld will always be greater than 1500 decimal.

This is the default frame type for Novell NetWare software version 3.12 and beyond; it is also used for OSI packets on IEEE 802.x LAN networks.

Ethernet 802.3 (Ethernet Raw)

The Ethernet 802.3 frame format has an 802.3 MAC layer header (as do Ethernet

802.2frames); however, it does not contain an 802.2 LLC header. Instead, Novell IPX is Þxed within the packet as the network layer protocol. This frame type Ð also known as Raw 802.3 Ð is the default frame type for Novell NetWare software before version 3.11. Since these frames do not carry the 802.2 header, they do not conform to the IEEE 802.3 speciÞcation. If you are using the Ethernet 802.3 Raw frame format, you should consider upgrading your Novell NetWare software to ensure interoperability with other communications protocols (unless your current network is not likely to be upgraded, and has no interoperability problems).

Note that IPX packets with checksums which provide data integrity (a feature of newer Novell NetWare releases) cannot be transmitted on Ethernet 802.3 networks. Note also that a single Ethernet can carry both Ethernet 802.3 and Ethernet 802.2 trafÞc simultaneously. The Novell server software will treat the two frame types as two logical networks (and function as an IPX router between the two networks).

Ethernet SNAP

To allow for proprietary protocols, such as IBMÕs SNA protocol, the Ethernet SNAP frame was created. This frame format extended the Ethernet 802.2 packet by improving the frameÕs byte alignment, and by allowing further protocol identiÞcation than the one byte LSAP protocol identiÞer of Ethernet 802.2 frames (which is reserved for standard protocols). Ethernet SNAP packets have an LSAP protocol ID of hex AA, indicating that they contain a SNAP (Subnetwork Access Protocol) packet. A SNAP packet, encapsulated within the Ethernet 802.2 packet, has a Þve byte SNAP header which is simply a Þve byte protocol identiÞer. The Þrst three bytes of the header indicate the Organizationally Unique IdentiÞer (OUI) Ð or the authority assigning the protocol ID Ð and the last two bytes indicate the protocol according to that authority. Note that for most protocols, the OUI is

0-0-0, and the type identiÞer is the standard Ethernet protocol ID. Although most Ethernet transport protocols use the Ethernet II frame format, the AppleTalk II protocol uses Ethernet SNAP (AppleTalk has its own unique OUI).

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Configuring FDDI Frame Translation Settings

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Cabletron Systems 2000 manual Ethernet 802.3 Ethernet Raw, Ethernet Snap

2000 specifications

Cabletron Systems was a prominent company in the networking and communications industry during the late 20th century, and by the year 2000, it had established itself as a leader in providing high-performance networking solutions. The company was known for its innovative approach to network architecture and its commitment to delivering reliable products that enabled seamless connectivity in various environments.

One of the primary features of Cabletron Systems in 2000 was its advanced networking technologies, including Local Area Network (LAN) and Wide Area Network (WAN) solutions. The company specialized in developing multi-layer switches that could efficiently manage traffic and deliver high-speed data transfer. Their products were particularly popular in enterprise settings, where network performance and reliability were paramount.

Cabletron's solutions included a range of products, from Ethernet switches to routers, which were designed with scalability and flexibility in mind. This allowed businesses to adapt their networks to accommodate growth, without the need for a complete overhaul of their infrastructure. The company’s Integrated Networking Architecture (INA) was a significant innovation during this period, enabling efficient communication and management of diverse network resources.

Another major characteristic of Cabletron Systems was its commitment to interoperability. The company’s products were designed to be compatible with several industry standards, ensuring that organizations could easily integrate Cabletron solutions into their existing networks. This focus on compatibility helped to foster collaboration among different devices and systems, further enhancing network efficiency.

Security was also a key feature of Cabletron’s offerings in 2000. With growing concerns about data breaches and unauthorized access, the company incorporated advanced security measures into its products. These features included robust authentication protocols, encryption options, and secure management interfaces, which helped safeguard sensitive data during transmission.

Customer support and service were paramount to Cabletron Systems' business model. The company provided extensive resources, including training and technical support, to ensure that customers could maximize the potential of their networking solutions. This dedication to customer satisfaction contributed significantly to Cabletron’s reputation in the marketplace.

In summary, Cabletron Systems in 2000 emerged as a frontrunner in the networking industry, characterized by its innovative technologies, commitment to interoperability, emphasis on security, and strong customer support. Their products and solutions were designed to empower businesses, helping them achieve greater efficiency, scalability, and reliability in their network operations.