Information Technology News Archive

1996 - 2017

UCInet Performance Considerations

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In the last NACS-News, we presented an overview of UCInet (see http://www.nacs.uci.edu/news/97.9.html). Continuing in our UCInet series, we examine some important UCI network performance issues below.

Performance at “the Edges” of the Network

A key network performance consideration is how networks are used within departments and among other groups of people who work together (workgroups). E-mail is exchanged, data and programs are accessed from local servers, printers are shared, and so forth. In the best case, members of a given workgroup are connected to a single Local Area Network (LAN). These workgroup LANs constitute the “edges” of UCInet.

Workgroup LAN performance is often limited by the shared 10 Mbps (Megabits per second) Ethernet speed typical of most campus LANs. Shared Ethernet requires all users to share bandwidth – the more users that are added to the LAN, and the more the network is used, the slower the network becomes. In fact, a single user can unknowingly monopolize shared network bandwidth, and slow response for everyone else.

When workgroups are split over multiple LANs, communication must travel through multiple network “routers” and the network backbone. Latency (response time) in this case is always worse than in single-LAN workgroups. Routers require more time to do their work than LAN switches or hubs, because their task is more complicated, and resource intensive.

Networking in many UCI workgroups currently suffers from LANs with too many computers sharing bandwidth, and from being split across multiple LANs. There is no “quick fix”, as network wiring in many UCI buildings will not support new, higher speed network technologies such as “Fast Ethernet”.

Backbone Considerations

UCInet’s backbone consists of six subnets, five of which use 10 Mbps ethernet, and one of which uses a 100 Mbps Fiber Digital Device Interface (FDDI) ring. The speed of traffic across the backbone depends on which of these subnets is required according to the source and destination of the traffic.

Another issue is the age of routers (up to 8 years old) on the slower UCInet segments. Older routers cannot support current software revisions, in much the same way that older PCs cannot run new system software like Windows NT. Important new features cannot be employed without replacing these routers. The good news is that there is bandwidth available on the FDDI backbone ring to support some additional, new routers and LANs as older routers are replaced.

The Internet and other Considerations

UCI’s off-campus connection can handle more traffic than is currently flowing through it. Unfortunately, the Internet itself has become so slow that some people are expanding the acronym WWW to World Wide Wait! A typical Web request can suffer from a variety of bottlenecks including slow Domain Name Service (DNS) lookup of host names, congestion on networks traversed en-route, a slow destination network, or a slow destination system. Slow response is one motivation for the recent nation-wide interest in a “new” Internet, which will address many of these problems.

UCI’s own network services, such as campus DNS, can also contribute to slow network response if not upgraded to handle expanding demand.

What’s the Plan?

Improving the speed and configuration of campus LANs is a critical UCI network need, as is the upgrade of data wiring and network backbone components. There is much to be done. We will discuss current plans and considerations next time.

NACS Staffing News

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TED GIELOW

Ted Gielow has joined NACS as a UNIX system administrator (SysAdmin). Ted, who replaces Sinclair Fleming, comes to us from the UCI Libraries’ Systems group, where he worked after having spent several years with NACS as a part-time computer operator and systems programmer.

Ted is the SysAdmin for UCI’s new Hewlett Packard SPP2000 parallel-processing scientific computing system. He will also play a number of other roles, including SysAdmin for NACS’ Orion UNIX service. His e-mail adress is TAGielow@UCI.EDU.

ADRIAN BORBON

Replacing Alex Wu, NACS’ new midnight to 8 AM computer operator comes to us from UC Riverside where he is a junior majoring in Computer Science. Adrian is a fan of baseball and classic cartoons; his e-mail address is ABorbon@NACS.UCI.EDU.

UCI Network Overview

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With the growing utilization of electronic communication in all aspects of University affairs, the campus network (UCInet) has become a critical campus asset. As communication needs continue to grow and change, the network must be maintained and enhanced to keep up. This requires a substantial campus investment. To facilitate discussions, NACS seeks to broaden campus understanding of network issues and options. Toward that goal, this article summarizes the layout and important components of UCInet. Subsequent articles will address current performance issues and planned improvements to UCInet.

UCInet may be logically grouped into six fundamental components, as follows:

1. Departmental and organizational LANs (Local Area Networks);
2. The campus backbone;
3. Network services;
4. WAN (Wide Area Network) connections;
5. Internet connectivity;
6. Remote access (e.g., modems and related equipment)

Departmental LANs, which connect to the backbone via devices known as routers, may be viewed as the “edges” of the network. UCI has a diverse collection of LANs. Most operate as “shared Ethernet”, meaning that connected computers “take turns” utilizing the network’s 10 Mbps (Megabits Per Second). LANs provide communication between computers within departments, and the routers they connect to provide links to the campus backbone and the services UCInet supports.

The UCInet backbone is the binding tie that connects LANs, the Internet, and other networks, such as the UCI Medical Center. It may be viewed as the “core” of the network. UCInet’s backbone has about fifty routers, each with multiple interfaces, for a total of about 350 LAN interfaces on campus.

“Network services” are computer-based services required by all users of the network. One example is the campus Domain Name System (DNS) servers, which provide translation of network names to network addresses. Applications such as Netscape cannot connect to a Web site until a DNS server answers a query for translation of a domain name to an Internet address.

Network services operate behind the scenes and are transparent to users. When a Web server fails to connect to a Web site, a user cannot distinguish between a network outage and a bad DNS lookup. In fact, one may cause the other!

UCInet has several WAN links to support outlying campus facilities. These links allow network users at sites like the Medical Center to appear as if they are on campus, albeit at slower speeds. “T1” (1.5 Mbps) WAN links are six times slower than the standard 10 Mbps Ethernet now widely in use.

Internet connectivity is provided throughout UCInet from another network called UCnet, which connects all UC campuses together. UCnet currently operates at a speed of 10 Mbps. However, UCI and UC Berkeley connect to UCnet and the Internet at “T3” (45 Mbps) speeds, as they are the UCnet network access points for the Internet.

Remote access to UCInet is accomplished via the campus modem pool and the Internet. Users may dial-in to UCInet through the modem pool or access UCI systems through their own Internet Service Provider.

UCInet is a diverse collection of networking and computing technologies which supports over 14,000 computers, printers, hubs, routers and other network devices, plus several hundred dial-in connections and countless visits from the Internet. In our next NACS-News network article, we will discuss UCInet’s most significant performance issues.

NACS Staffing News

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NANCY MORALLO

Nancy Morallo has filled a vacancy left by Kim Carpenter in NACS’ Business Office. Nancy was previously employed by the YMCA of Orange County as an Accountant Assistant, and was also a secretary and Human Resources Specialist at the American Life Insurance Company.

Nancy is in charge of a number of administrative functions in NACS and is also involved in coordinating meetings among NACS staff and others at UCI. She may be reached via MMORALLO@UCI.EDU or 824-8920.

ERIC FRIEDMAN

Eric Friedman recently joined NACS’ Academic Applications group. Eric holds a B.A. and an M.A. in Comparative Literature from Case Western Reserve University and is a candidate for the PhD in Comparative Literature at UCI, where he is writing a dissertation on the contemporary artist’s book in France, Germany, and the United States. He recently presented a workshop on “Getting Your Students Published on the WWW with a Minimum of Fuss: Four New Teacher Tools” at the International Conference on Computers and Writing.

As a part-time student employee of NACS, he participated in the development of many of the key technical components of NACS’ support for the campus’s Electronic Educational Environment (EEE). Joining NACS’ professional staff, he will serve as a faculty contact, supporting use of EEE and its further development in response to faculty suggestions. His contact information is FRIEDMAN@UCI.EDU and 824-6374.

UCI CONNECTION TO VERY HIGH SPEED NETWORK (vBNS)

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Vice President Al Gore

Vice President Al Gore

Vice President Gore announced on May 20 that the Corporation for Education Network Initiatives in California (CENIC) will receive a grant of nearly $4 million from the National Science Foundation (NSF). The grant will allow UCI and other California research universities (UC campuses, Cal Tech, Stanford and USC) to connect to the very high-speed Backbone Network Service (vBNS). UCI will gain an “OC-12” (622 mega-bits/second) network connection to participating research institutions; this connection is expected to be in place during the summer of 1998. The award is part of the Federal Government’s Next Generation Internet (NGI) initiative — a total of $12.3 million in grants to 35 research institutions across the United States was included in the May 20 announcement.

This grant will facilitate CENIC’s “CalREN-2” high-speed California network project, and will allow UCI to eventually take advantage of developments that result from “Internet-2”, NGI and other national initiatives. You may be interested in browsing some of the Web material cited below:

Network Initiative URLs:

May 20 Press release:
http://www.nacs.uci.edu/news/press-release-vbns.html

Federal Government NGI (Next Generation Internet):
http:://www.ngi.gov

CENIC (Corporation for Education Network Initiatives in California):
http://www.ucop.edu/irc/projects/CENIC.html

Very high speed backbone service:
http://www.vbns.net