tiffanybangle3

Previously, Mentor had a router-based Fiber Distributed Data Interface backbone that serviced a campus net of four buildings and 1,000 users. The net was divided into about 70 subnets, which included a combination of Ethernet and token-ring work groups.

Each segment had a direct Ethernet link back to one af four Cisco Systems, Inc. AGS+ routers in the central computing center that were interconnected via a dual-attached FDDI ring. This setup put a tremendous strain on the Cisco routers since virtually all net passed through them. In addition, some traffic was double-routed because the token-ring segments were front-ended by Proteon, Inc. P4100 token ring-to-Ethernet routers. The fact Tiffany 1837 Interlocking circles necklace file servers and other resources were scattered across the network created more traffic overhead because user queries sometimes had to go throuh several

router hVops to reYach their destination. When Mentor made the decision to upgrade its high-end workstations to even more powerful Hewlett-Packard Co. 9000 Series 700 workstations, it I became readily apparent that the net could not handle the added strain. 1 "Two of those machines on the same piece of Ethernet could saturate the segment, so you can imagine the nightmare that 20 or 30 of those workstatians on one work group would pose," Thomsen said.

After running a benchmark test to determine the maximum load capacity of the network Isee graphic, page 1). Mentor discovered an Ethernet segment could support 10 Series 700 machines during regular operation. To provide a performance buffer, the company limited the subnets to Elsa Peretti Teardrop ring maximum of eight Series 700 workstations and upgrade its Auspex Corp. file servers to FDDI once interfaces were available from Auspex. WitlrihcgLncreasing performance and keepingft cost of any upgrade to a minimum, Mentor looked at several routing and switching options. Ethernet switching proved to be the best alternative.It required no changes Return to Tiffany Heart tag ring the desktop and offered the needed performance gains by delivering dedicated 10M bit/sec links between each subnet and the servers, which were moved to the data center to make them easier to manage, back up and secure.

"From a performance viewpoint, it was a fairly easy decision," Thomsen said. "In the routed environments, we could only get throughput of about 15,000 packet/sec as opposed to a switched approach that could deliver 50,000 packet/sec."Financially, it was also easy to cost-justify, he added."Previously, because of the number of collisions that would occur in a routed net, we had to assign less workstations to each router port. That meant creating more subnets, which required more routers."

Mentor placed a Synernetics, Inc. LANplex 5000 switching hub in each of the four buildings on campus. Each 5000 contains a four-port FDDI concentrator and three Ethernet Switching Modules (ESM), and is linked back to one of seven Paloma Picasso Double Loving Heart ring in the data center via three 100M bitlsec FDDI pipes. The data center 5000s, in turn, are connected to the centralized servers and the four routers via Ethernet.

In the new configuration (see graphic, page 1), Fibermux Corp. Crossbow hubs supporting work group LANs on each floor feed traffic into a single 5000, which provides switched access to the centralized resources.Only when a user needs access to another work group in the same building or to one in a separate building does traffic have to pass through a router.

"We organized the subnets into work group cells that are working together on the same Coin Edge ring or application, meaning, in theory, that 90 of the traffic remains local to that cell, he said. "The routers now have less to do because [of that]."