Introduction
1–3
Full–duplex mode uses two independent data paths for simultaneous transmission in both
directions. These independent, parallel full–duplex paths are extended throughout the
entire switching fabric, which allows connections to be made from both halves of a full–
duplex connection to two separate half–duplex ports. In addition to autosensing the
transmission speed of the connected device (at 10 Mb/s or 100 Mb/s), the DEL8X can
autonegotiate its transmission mode at half– or full–duplex mode if the connected device
also supports this function. (See the Communication Mode section in Chapter 4 for more
information.)
Fast Ethernet
The DEL8X provides a simple cost–effective method to integrate existing networks with
Fast Ethernet. This switch provides an ideal front–end interface for small to medium
networks. By offering 100 Mb/s full–duplex connections to high–utilization devices such as
departmental servers and high–performance workstations, the DEL8X relieves the
performance bottleneck found on most client–server applications, where many client
stations compete to retrieve data from a few servers.
To install the DEL8X, use your current network infrastructure, including wiring and
network interface cards (NICs). Afterwards, you can configure and monitor the system
using the DEL8X front panel, which includes an extensive array of LEDs for monitoring
the unit's overall condition, as well as the status of each port.
Switching Methods
The DEL8X can simultaneously forward frames among up to eight different shared or
dedicated Ethernet segments. With extensive buffering, it can support connections between
any segment pair, whether 10 Mb/s or 100 Mb/s at half– or full–duplex mode. The fully
parallel internal design allows the DEL8X to easily maintain media speed frame transfer
between multiple port pairs.
The switching methods used by the DEL8X are described in the following sections.
Cut–Through Switching
The DEL8X performs “on–the–fly” cut–through switching, which sends a packet to the
other port according to the destination address scanned from the packet header. This
technique reduces the latency of packet transmission to 20 microseconds or less. Compared
to approximately 800 microseconds for a bridge or 1800 microseconds for a router, both of
which have to store the entire packet before it can be forwarded, the DEL8X can deliver a
quantum improvement to network performance.