Physical Science's Network Upgrade 1998

Summary: This document is a detailed account of how a network is upgraded. The Physical Sciences network was upgraded in 1998.

The New Network in Physical Science 

The three main components of OIT' efforts to enhance UCI's network are:

1. upgrading the infrastructure in UCI buildings at the "edges of the network,"
2. enhancing the backbone network that ties buildings together and connects the campus to outside networks, and
3. participating in off-campus network initiatives that increase our connectivity to the rest of the world.

The upgrades required in UCI buildings are substantial, and as of this writing OIT has completed two - in Information and Computer Science, and in Physical Sciences. This page outlines the scope and benefits of the new network in Physical Sciences as an example of what the "network edge" enhancements provide campus network users.

The NetFlow Feature Card II 

An important concept in Physical Science's new network is "switching" as contrasted with "routing". Switching is very fast, and operates at the lowest, most efficient level of TCP/IP networking. Routing is slower, as it requires more table lookups and processing of routing paths. Where ever packets need to be moved around the network, modern design maximized the use of switches whenever possible, in preference to the use of routers.

The major new building network devices installed in Reines and Rowland Halls are Cisco Systems Catalyst 5500 Network Switches, which replace the routers previously in operation there. Each switch includes a Route Switch Module (RSM), which are "routers on a card" with the same capabilities as Cisco's large 7500-series routers. However, because the router is effectively part of the switch, and because of a module known as a "Netflow Feature Card", the effective capacity for routing is 1.5 million packets per second. This is a substantial increase from the previous routers, which had a capacity on the order of hundreds of thousands of packets per second. Further, flows of packets may be identified, then switched rather than routed, allowing even better performance. This concept is typified by the catch-phrase, "Route-once, switch many."

A pictorial representation of Physical Science's new network follows:

Click on the image for a larger view. (The full image is 171k).

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The pure switching rate is wire-speed, the speed you would see when the network devices are removed so that only the "wire" is between the transmitter/receive pairs. In short, the switch does not slow down the travel of frames of data through the network. Both switches are connected to the backbone and to each floor using Fast Ethernet, in full-duplex mode, offering 200 Mbps bandwidth switch-to-switch.  Reines and Rowland hall are also connected together via 4 full-duplex Fast Ethernet pipes. Traffic between the two is load-shared over the 4 pipes.

The Physical Sciences Annex is connected to Reines Hall via 2 Fast Ethernet connections, and will soon be connected to Rowland Hall in the same fashion pending completion of the Physical Sciences fiber upgrade project. Once this is complete, traffic from any network in any of the three buildings will be able to move to any other network in each of the three buildings with no bottlenecks. Unlike Reines and Rowland Halls, the Annex has no local routing. Annex subnets are supported using VLAN technology, allowing the routers in the other two buildings to provide routing, when required. A Cisco Systems 2926F switch is employed as the building switch in the Annex. The Cisco 2926F switch is actually Catalyst 5000 technology, with 24 ports fixed into a non-configurable box, and has a Supervisor Engine just like the Catalyst 5500. This is not a "standard" workgroup switch but rather a powerful, compact switch capable of handling the load.  

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Rowland Hall is connected to the CS1 backbone core site in the ICS complex, and Reines Hall is connected to the Social Sciences Plaza core site. These are also full-duplex Fast Ethernet pipes, so the effective bandwidth between the UCInet backbone and the Physical Sciences complex is 400 Mbps. This bandwidth exceeds the current UCInet backbone, but will be no problem for the new backbone, when complete.

All desktops in the complex have available 10 Mbps switched Ethernet, and in some special cases 100 Mbps switched Ethernet has been deployed. All servers which provide departmental, school-wide, campus or Internet-wide services have also been given special Fast Ethernet connections. Every server and desktop location has at least one 10baseT jack supported by Category 5 wiring, supplanting the older coax 10base2 network. As shown in the diagram below, the Backbone Core is linked with Gigabit Ethernet, whereas buildings are connected by Fast Ethernet:

Detailed View of Network with New Core Backbone
Note: This view is a logistical blueprint for future connectivity on UCI's campus.
The results and locations may differ in some respects to the final design and/or implementation.

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What does all this mean?

Physical Science's backbone connectivity has improved, or will improve, by a factor of 40. Desktop connectivity has improved by a factor of at least 2.5 in most locations, and typically much more than that, up to a factor of 25. (For example, if enough users shared a subnet on the old network where they averaged around 400 Kpbs of bandwidth, the new switched 10 Mbps network provides an improvement factor of 25). Server connectivity has improved by a factor of anywhere from 2.5 to 250, depending on the previous state of the network where the server is connected. Finally, the number of packets which may be routed in Physical Science's network has improved by a factor of two orders of magnitude, from tens of thousands of packets per second to millions (1.5 per building, or 3 million collectively).

For More Information

Please contact Garrett Hildebrand (gdh@uci.edu), OIT' lead network planner, or see one of the references below:

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