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Introduction and Background Information Network Assessment Audit Network Diagram for Raytown School District Problem Definition Traffic Analysis for Raytown School District Specifications and Scope of Work Options and Recommended Solutions Network Diagram of Switched 100 MB Backbone

Network Assessment — Raytown C2

Introduction and Background Information

Raytown School District encompasses the city of Raytown, Mo., southeast of Kansas City. The district currently has 26 buildings mostly connected with wireless bridges. Five technical staff members provide support for approximately 2000 computer devices. The district currently is developing a three to five-year technology plan. They are upgrading their slow wireless links and replacing the DOS, Windows 3.1 and low-end Macintosh machines. They anticipate a bond issue in the Fall 2000 to finance these upgrades. They want MOREnet to provide feedback on their network architecture and present an upgrade path.

A Director of Technology oversees technology for the district and coordinates with a Manager of Technical Support. The technical support manager is a veteran of over ten years and possesses above average technical skills. He employs hardware, software, networking and help desk techs.

The district hired a vendor to evaluate the district's building wiring and to upgrade the elementary schools from 10BASE-2 to 10BASE-T wiring. The Director expects to put Raytown School District in the forefront of technology. They want MOREnet to provide an evaluation of their network and offer suggestions to help them achieve this goal.

Network Assessment Audit

Raytown School District has a T1 connection to MOREnet that averaged 5.5 percent usage last year. The District is in the middle of upgrading the campus wireless links so the network diagram below illustrates work in progress.

The MOREnet Internet connection comes into Raytown High School and collects the northern part of the district using wireless bridges. Multi-mode fiber interconnects several buildings at Raytown High School. A second collection point for the southern portion of the district, South High, picks up buildings in the southern half of the district using wireless bridges. Some downstream sites are daisy chained due to logistics of the land. The two high schools interconnect with a throttled back 11 Mbps wireless bridge. With a high number of bridges at several wireless collection points, most of the bridges are throttled back to half their throughput due to frequency crosstalk.

Raytown has a large number of hubs throughout the district. Bridges connect to a hub before traversing to the wiring closet. Most buildings have a secondary wiring closet, which adds additional hubs to the network architecture. The business office has a router, Watch Guard Firewall and an Alpha server. The VocTech center has a small firewall separating a test lab.

The district is 10BASE-T wiring, with the exception of the elementary schools wired with 10BASE-2. Two firewalls protect the Business center and VocTech test lab. Most of the 2000 IPs are assigned to the MOREnet Ethernet port, so the district basically is a large flat bridged network of 2000 workstations.

The school district is a mix of Windows and Macintosh machines; many of these workstations are beyond their usefulness. Novell 4.11/5.x servers manage mail on low-end Pentiums. NetWare is used for Proxy, file and print services on the network. Several Mac servers provide file, print and workstation management for the Macintoshes. IPX, IP and Apple talk protocols are used throughout the network. Filtering IPX and AppleTalk is performed at each of the wireless bridges. GroupWise mail gateway and two proxy Border Servers (with a single network card) are additional services on their network.

The city negotiated a single strand of fiber with the cable company to connect 80 percent of the district. Three buildings are currently being converted. They are replacing central hubs with switches to allow for the 100 Mbps switched fiber backbone. Two sites using ISDN now connect with wireless bridges.

Network Diagram for Raytown School District

Figure 1. Network Diagram for Raytown School District

Problem Definition

The site had an incident last year during the Y2K upgrade process. When their 2500 router was replaced with a 1601 router their network died. We sent a 2501 Y2K-compliant router and their network worked fine. The router showed excessive collisions and an invalid route caches from the Alpha. They notified the business office and found a pinch in a fiber run. They reported this fixed their slow network problem.

The site indicated that the network speed is fine; however they have reports of e-mail users dropping connection to the server when they access GroupWise mail.

From the site visit observations, I found an excessive number of hubs, which violates the 5-4-3 Rule. Hubs were found at the wireless bridge collection points, thus sharing traffic over all connected links. The Business office has some Ethernet wire tied to a power conduit. Two Border Servers with one network card, when used with a hub, puts additional traffic on the wire. They are running multiple Class C addresses on the router which forces routing on the wire. A large number of bridges on their network are throttled down causing the building links to show congestions during session.

The utilization reports for the year show a low usage on the serial link to the Internet. A utilization of 5-6 percent is recorded on a yearly average. Peaks can be seen at 56 percent inbound.

System: Raytown-SD.gw.more.net in Raytown, Mo.
Max Speed: 1536.0 Kbps (frame-relay)

Traffic Analysis for Raytown School District

Monthly Graph (2 hour average)

Max In: 868.7 Kbps (56.6%) Average In: 42.2 Kbps (2.7%) Current In: 14.2 Kbps (0.9%) Max Out: 197.1 Kbps (12.8%) Average Out: 8344.0 bps (0.5%) Current Out: 3728.0 bps (0.2%)

Yearly Graph (1 day average)

Max In: 452.0 Kbps (29.4%) Average In: 85.0 Kbps (5.5%) Current In: 39.7 Kbps (2.6%) Max Out: 499.1 Kbps (32.5%) Average Out: 17.8 Kbps (1.2%) Current Out: 6120.0 bps (0.4%)

Specifications and Scope of Work

The scope of this visit was to gather information on Raytown School District's network and to assess their direction. A detailed network diagram is not possible due to the dynamics of their summer upgrades in progress. The future direction of the district's network includes the limitation of the cable fiber due to logistics of the buildings and the fiber trunks.

They are replacing some of their switches and upgrading their Border Servers to higher end hardware. They are connecting most of their buildings using single strand fiber. They want to use the fiber provided by the cable company as a stepping stone to move to a fully switched redundant backbone that will scale into the future and allow for higher end solutions like Gigabit Ethernet, ATM, video or voice over IP.

Options and Recommended Solutions

We discussed improvements to the existing architecture by limiting segments between hubs and moving to a star network design, as well as adding switches to the backbone and connecting secondary wiring closets using multi-mode fiber to increase the reliability of their network infrastructure and allow for future scalability.

They can reduce the number of servers by upgrading hardware and adopting a one-server platform. Moving the servers to a central location can be done once the 100 MB backbone is operational. This change will reduce the cost of administration of network services and software support. The site is planning to add four more Border Servers for a total of six. This option might be overkill, but if configured with two network cards and implemented with a hieratical web caching, slower links could improve their performance on the network while they secure devices behind the server.

The current subnetting on the network causes downstream links to route back to Raytown High when accessing internal devices on a different subnet. Adopting a super-subnet on large LAN segments will help reduce this extra traffic.

Workstation management is not being used with the exception of some late model Macs. Locking PC workstations down in labs and public access locations will reduce the cost of support from the staff. Using Windows System Policies, ZEN-Works or Windows NT workstation can achieve this goal with little effort. Adopting an AUP for supported applications on workstations will limit application support from the staff.

The staff appears to be very knowledgeable in workstation support and internal wiring. The district has a slight void in server and networking knowledge that can be brought up to date easily by adopting a yearly training plan to keep staff up to date on current support needs.

Network Diagram of Switched 100 Megabit Backbone

The above diagram is based on the availability of fiber trunks from the cable company. Some outlying sites will stay wireless links, but with only one antenna per tower, the links should support a full 11 Mbps connection without frequency crosstalk.

Overall the district appears to be on the right path for improving their network. It will be difficult to analyze the network until this major upgrade phase stabilizes.