FDDI Applications

If the frame is exiting the FDDI ring through another FDDI/Ethernet bridge, the FDDI frame must be converted back into an IEEE 802.3/Ethernet frame. As there are four potential Ethernet frame types to which the two FDDI frame types can be translated, you must determine which translation options you want in effect — depending on which network protocols and applications are being run on the destination network.

In addition, there are frame size differences between FDDI (which allows a maximum frame size of 4500 bytes) and Ethernet frames (1518 byte maximum, excluding preamble), so FDDI frames may need to be fragmented before being bridged onto an Ethernet network.

The Frame Translation window lets you set the parameters for frame translation and fragmentation when Ethernet traffic needs to traverse an FDDI ring. The frame types that you select for translation will depend on which higher-layer communications protocols and software you are running on the network segments connected to your Ethernet-to-FDDI bridge. Each frame type and its usage is described below.

Ethernet Frames

The HSIM-F6 supports translation of the following four Ethernet frame types:

Ethernet II

Ethernet II is the Novell NetWare designation for the basic Ethernet frame type (also commonly referred to as Ethernet or Ethernet DIX). This frame format has an Ethernet II MAC header with a two byte Ethernet Type field. The Type field contains a protocol ID which indicates the upper layer protocol (e.g., XNS, DECnet, TCP/IP, etc.) used in the Data field of the packet. Most current transmission protocols, including TCP/IP, use the Ethernet II frame format, as do networks running Apple’s AppleTalk 1 protocol and Digital’s DECnet protocol.

Note that the Type field of an Ethernet II frame will always have a decimal value greater than 1500, so that it can be differentiated from the Length field of Ethernet 802.2 frames (described below).

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 field is eliminated and replaced with a two byte Length field, 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 field (the LSAP – or LLC Service Access Point value) which provides the frame’s protocol ID. Ethernet 802.2 packets are differentiated from Ethernet II packets because the Length field will always have a decimal value of 1500 or less (since the data field in Ethernet frames cannot be greater than 1500 bytes), and the Ethernet II Type field will always be greater than 1500 decimal.

Configuring FDDI Frame Translation Settings

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Enterasys Networks 2000 manual Ethernet Frames
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2000 specifications

Enterasys Networks, a key player in the networking space in 2000, was renowned for its innovative solutions that combined high-performance networking with robust security features. Founded with the vision of providing enterprise-level networking infrastructure, Enterasys positioned itself to cater to the growing demands of business networks during the dot-com boom.

One of the main features of Enterasys Networks was its focus on delivering secure, scalable networking solutions that could seamlessly integrate with existing enterprise systems. The company developed a range of products including switches, routers, and wireless solutions that were designed to optimize performance while ensuring security at every layer. Their core offerings provided businesses with the reliability required to handle increasing volumes of data traffic.

A standout technology of Enterasys was its identity and access management solutions. These technologies allowed organizations to control who could access network resources and under what conditions. This was particularly crucial in a time when cyber threats were on the rise, and businesses were becoming more aware of the need for strict network security protocols. The features included role-based access control and authentication measures, which were fundamental in safeguarding sensitive information.

Enterasys also introduced intelligent networking features, which enabled dynamic traffic management and prioritization. This technology helped organizations optimize their network performance by automatically adjusting to changing workload demands. Such capabilities were essential for businesses relying on bandwidth-intensive applications and services.

The company also embraced the rising trend of wireless networking, providing solutions that combined wired and wireless technologies for a unified experience. Enterasys Wireless LAN solutions were groundbreaking at the time, offering seamless connectivity and security to mobile devices, thereby enhancing productivity and flexibility within enterprise environments.

In addition to hardware, Enterasys developed network management software that simplified the administration of complex networks. This software enabled IT professionals to monitor performance, troubleshoot issues, and implement security policies efficiently.

Overall, Enterasys Networks in 2000 was characterized by its commitment to delivering secure, intelligent networking solutions that catered to the needs of modern enterprises. With its innovative technologies and features, Enterasys played a significant role in shaping the networking landscape, laying the groundwork for future advancements in network security and management.
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