50-Port Dual Web Rack Switch
2
internetworking technologies. And with expected advances in the coming years in silicon technology
and digital signal processing that will enable Gigabit Ethernet to eventually operate over unshielded
twisted-pair (UTP) cabling, outfitting your network with a powerful 1000-Mbps-capable
backbone/server connection creates a flexible foundation for the next generation of network
technology products.
Fast Ethernet Technology The growing importance of LANs and the increasing complexity of desktop computing applications
are fueling the need for high performance networks. A number of high-speed LAN technologies have
been proposed to provide greater bandwidth and improve client/server response times. Among them,
100BASE-T (Fast Ethernet) provides a non-disruptive, smooth evolution from the current 10BASE-T
technology. The non-disruptive and smooth evolution nature, and the dominating potential market
base, virtually guarantees cost-effective and high performance Fast Ethernet solutions.
100Mbps Fast Ethernet is a standard specified by the IEEE 802.3 LAN committee. It is an extension
of the 10Mbps Ethernet standard with the ability to transmit and receive data at 100Mbps, while
maintaining the CSMA/CD Ethernet protocol. Since the 100Mbps Fast Ethernet is compatible with all
other 10Mbps Ethernet environments, it provides a straightforward upgrade and takes advantage of the
existing investment in hardware, software, and personnel training.
Switching Technology
Another approach to pushing beyond the limits of Ethernet technology is the development of switching
technology. A switch bridges Ethernet packets at the MAC address level of the Ethernet protocol
transmitting among connected Ethernet or Fast Ethernet LAN segments.
Switching is a cost-effective way of increasing the total network capacity available to users on a local
area network. A switch increases capacity and decreases network loading by dividing a local area
network into different segments, which don’t compete with each other for network transmission
capacity.
The switch acts as a high-speed selective bridge between the individual segments. The switch, without
interfering with any other segments, automatically forwards traffic that needs to go from one segment
to another. By doing this the total network capacity is multiplied, while still maintaining the same
network cabling and adapter cards.
Switching LAN technology is a marked improvement over the previous generation of network bridges,
which were characterized by higher latencies. Routers have also been used to segment local area
networks, but the cost of a router, the setup and maintenance required make routers relatively
impractical. Today switches are an ideal solution to most kinds of local area network congestion
problems.
A VLAN is a group of end-stations that are not constrained by their physical location and can
communicate as if a common broadcast domain, a LAN. The primary utility of using VLAN is to
reduce latency and need for routers, using faster switching instead. Other VLAN utility includes:
• Security, Security is increased with the reduction of opportunity in eavesdropping on a
broadcast network because data will be switched to only those confidential users within the
VLAN.
• Cost Reduction, VLANs can be used to create multiple broadcast domains, thus eliminating
the need of expensive routers.
• Port-based (or port-group) VLAN is the common method of implementing a VLAN, and is the
one supplied in the Switch.