Designing a Wireless Enterprise Network: Hospital Case Study • Chapter 6 213 could possibly interfere with medical equipment.This is one area where research is very important. ■ Are there any existing monthly costs that can be replaced with wireless link? The hospital administration staff wants to review the costs of the wireless network versus the current leased line system.The hospital Board of Directors is very cost-conscious. ■ Are there any constraints in placing wireless equipment and antennas in computer rooms, communication closets, walls, roofs, offices, or conference rooms? If you can identify con- straints at this time, you can save a lot of time during the imple- mentation phase. ■ What are the hospital plans for adding or deleting any office buildings? How accurate are the plans? Changes to the physical structure should be identified early to save time and effort. These questions are important in understanding the current environment.They also help you design for constraints or limitations. Evaluating Network Requirements After meeting with the hospital IS team, you determine the following requirements and constraints. It is important to define all requirements and constraints to ensure that your wireless solution falls within the expectations of your customer. In the current physical network, all the satellite buildings use internal Category 5 Unshielded Twisted Pair (UTP) wiring.The Administration department expressed the need for LAN access in conference rooms in the main building. Since all employees are receiving laptop computers, all departments will require the ability to access the network from any- where in the satellite buildings and in the conference room in the main hospital building.All users want the ability to use their laptops anywhere in any of the buildings.This will improve productivity because the med- ical staff often travels between the main hospital and the satellite build- ings.The IS manager will provide building floor plans but foresees no physical limitations for placing wireless devices in the satellite buildings. www.syngress.com 152_wan_06 6/21/01 3:24 PM Page 213 214 Chapter 6 • Designing a Wireless Enterprise Network: Hospital Case Study The satellite buildings are not owned by the hospital, they are leased. The satellite buildings connect to the main hospital via leased T-1 links. These leased links have become a recurring cost that the IS manager would like to reduce or eliminate.These links are highly utilized and the IS staff has received complaints from the different medical groups.There are no fiber lines to the satellite buildings and the cost to install fiber is not within the current budget.The IS staff wants to implement wireless technology to provide links from the main hospital to the satellite build- ings.The wireless network must provide security and encryption.The IS staff requires some level of redundancy for the site links. Hospital officers mention that there are immediate plans to increase the hospital employee population. However, they want the developed solution to be scalable to support additional buildings in the future.They also express concerns about using radio frequencies in main hospital building, so they want to limit the wireless devices to conference rooms and site links within the hospital building. Assessing the Satellite Buildings’ Physical Landscape The IS manager has provided the floor plans. All of the satellite buildings were designed around the same floor plan, shown in Figure 6.1. Notice that there are communications and mechanical rooms in the center of the floor plan area; these rooms may generate noise and affect the wire- less design.The rest of the floor plan is open-area space with offices and a conference room.You will perform a walkthrough in each of the buildings to visually assess the environment. Evaluating the Outside Physical Landscape The hospital campus area topography is shown in Figure 6.2.The main hospital is eight stories high and is separated from all other buildings with roads located in an urban zone.There is a park with high trees at the south of the main hospital building. Each satellite building is four stories high.There is a clear line-of-sight from the hospital to each www.syngress.com 152_wan_06 6/21/01 3:24 PM Page 214 Designing a Wireless Enterprise Network: Hospital Case Study • Chapter 6 215 satellite building, and between the satellite buildings, except from Building 301 to Building 201.We must take this information into con- sideration to ascertain the redundancy requirements. www.syngress.com Figure 6.1 Satellite Building Floor Plan Elevators Mechanical Room Communications Room Conference Room Office Office Office Office Office Office Office Office Office Office Office Office Office Office Office Break Room Figure 6.2 The Topology of the Jones Hospital Buildings Main Hospital Building Building 301 Building 201 Building 200 Building 100 Building 300 Building 101 Park 200 Meters 152_wan_06 6/21/01 3:24 PM Page 215 216 Chapter 6 • Designing a Wireless Enterprise Network: Hospital Case Study Evaluating the Current Network The current campus network has a router located in the computer center of the main hospital building with six serial interfaces. Each serial interface is used to connect to each of the satellite buildings via T-1 lines. Since the outside infrastructure is not privately owned, the T-1 lines are leased via the local exchange carrier.There is no fiber infra- structure between the buildings. Each building has category 5 UTP wired infrastructure terminating into closet patch panels. Each LAN drop is terminated into a LAN switch. Fiber cables connect the LAN switches to the building router. As shown in Figure 6.3, the floor LAN switches connect to the building router, which has the T-1 line to the main building.This architecture does not provide for any redundancy, and the hospital wants to over- come this problem in the current architecture. Evaluating the Hospital Conference Room Networking Landscape An assessment of the conference rooms in the hospital building shows four existing LAN drops in each room.The conference room layout is www.syngress.com Figure 6.3 Current Network Topology Main Hospital Router Building 301 Router Building 201 Router Building 200 Router Building 101 Router Building 300 Router Building 100 Router T-1 T-1 T-1 T-1 T-1 T-1 LAN Switches 152_wan_06 6/21/01 3:24 PM Page 216 Designing a Wireless Enterprise Network: Hospital Case Study • Chapter 6 217 shown in Figure 6.4. Because the network connection already exists, and there is easy access to the drop, one of these drops can be used to place the access point bridge. As an additional benefit, the building infrastruc- ture permits wireless LAN access from nearby offices. Designing a Wireless Solution Once we define the requirements and baseline the current network, we can move from the planning phase to the design phase. For convenience, we’ll divide this wireless design project into three smaller projects, com- partmentalizing the large project into smaller ones to make it easier to provide a solution for each project on a smaller scale.The first project provides wireless access in the satellite buildings.The second project simply adds wireless LAN connectivity to the conference room in the main hospital building.This enables the employees with wireless connectivity through the wireless interface cards in their laptops.The third project adds the wireless links from the satellite buildings to the main hospital and then adds the redundant links between each pair of satellite buildings. Let’s review the design requirements: ■ Provide wireless access for laptops in all satellite buildings. ■ Provide wireless connectivity in conference rooms in the main hospital building. www.syngress.com Figure 6.4 Conference Room Layout LAN Drops Hall Office Office Conference Room 152_wan_06 6/21/01 3:24 PM Page 217 218 Chapter 6 • Designing a Wireless Enterprise Network: Hospital Case Study ■ Provide a replacement to the leased T-1s that connect the satel- lite buildings to the main hospital building. ■ Provide increased bandwidth to the satellite buildings. ■ Provide redundancy to the satellite buildings. ■ Maintain a level of security and encryption for the links. Project 1: Providing Satellite Building Access When designing a wireless network in an enterprise building, you must determine the placement of antennas and access points for best coverage. In this example, the mechanical room, elevators, and communications room are sources of frequency interference that you need to consider.A single omnidirectional antenna might be capable of covering the office area in a satellite building (over 100 feet). However, with the interference items to consider, it would be better to place omnidirectional antennas (and access points) in each hallway, as shown in the Figure 6.5, to get better coverage.Also, each access point can provide redundancy. If one access point fails, the other provides access to all computers on the floor. www.syngress.com Other Antenna and Access Point Bridge Placements There are several methods of placing antennas to have full coverage in a floor. Directional antennas could be placed in each of the four corners of the floor aiming at a 45-degree angle toward the center of the building. To verify antenna placement, place an access point bridge at each location and test its range with a laptop with a wire- less card. It is helpful to perform this test using a roll cart, so you can roll around the hallways, offices, and conference rooms to verify coverage. Designing & Planning… 152_wan_06 6/21/01 3:24 PM Page 218 Designing a Wireless Enterprise Network: Hospital Case Study • Chapter 6 219 The access point wireless bridges will be placed on shelves near the antennas.The Ethernet ports of the access point bridges will be con- nected to the LAN switches that serve the floor.The LAN switch must be configured to permit multiple media access control (MAC) addresses on the data port. Project 2: Providing Wireless Technology to the Conference Rooms For the conference room project, plan to install one access point wireless bridge. Users requiring wireless LAN connectivity will need to install wireless LAN network interface cards into their laptop computers.The access point will be configured as a bridge with the Ethernet port con- necting to the LAN jack. An antenna will be installed in the conference www.syngress.com Figure 6.5 Project 1: Placement of Access Point Antennas in Satellite Buildings Elevators Mechanical Room Communications Room Conference Room Office Office Office Office Office Office Office Office Office Office Office Office Office Office Office Break Room AP AP 152_wan_06 6/21/01 3:24 PM Page 219 220 Chapter 6 • Designing a Wireless Enterprise Network: Hospital Case Study room.This solution meets the requirement for access to the LAN from the hospital conference room. As shown in Figure 6.6, the access point is placed on a shelf on the corner of the conference room.A directional antenna is also placed on the corner providing access to the conference rooms and nearby offices. The LAN switch that serves the conference room drop must be config- ured to permit more that one MAC address on the LAN port.This same solution is applied to each conference room in each satellite building. Project 3: Providing Building- to-Building Connectivity There are many different ways to provide a wireless solution for Jones Hospital’s network. A single wireless link could be implemented between the hospital building and each satellite building, but this solu- tion would not provide redundancy. A full mesh could also be imple- mented, but it might be an overkill solution. The solution presented here is one design approach that meets the requirements. Let’s review the design requirements for this connectivity: www.syngress.com Figure 6.6 Project 2: Conference Room Solution Ethernet Port connected to LAN Drop Hall Office Office Conference Room AP 152_wan_06 6/21/01 3:24 PM Page 220 Designing a Wireless Enterprise Network: Hospital Case Study • Chapter 6 221 ■ Provide a replacement to the leased T-1s that connect the satellite buildings to the main hospital building. ■ Provide increased bandwidth to the satellite buildings. ■ Provide redundancy to the satellite buildings. ■ Maintain a level of security and encryption for the links. Based on the requirements, the existing lease lines will need to be replaced with wireless links from the main hospital building to each satellite building. Data encryption will be enabled to provide link secu- rity.The wireless links will provide increased bandwidth from 1.5 Mbps to 11 Mbps.To provide redundancy, we could link every building in a loop, but this would add additional cost to the solution.The redundancy goal can be accomplished by just adding wireless links between building pairs; for example, adding a wireless link between Buildings 100 and 101, Buildings 200 and 201, and Buildings 300 and 301. A high-level illustration of the proposed solution for Jones Hospital is shown in Figure 6.7. www.syngress.com Figure 6.7 Project 3: Proposed Building Wireless Connectivity Main Hospital Building Building 301 Building 201 Building 200 Building 100 Building 300 Building 101 Wireless Link 152_wan_06 6/21/01 3:24 PM Page 221 222 Chapter 6 • Designing a Wireless Enterprise Network: Hospital Case Study Describing the Detailed Design of the Building Links As previously described, we want to create point-to-point wireless links between buildings. Some vendors have wireless devices called outdoor routers that can provide a solution for Jones Hospital.We will create an architecture using the existing routers in each building.The access-point outdoor routers will connect via Ethernet to the hospital router.We’ll use each outdoor router to create point-to-point links to each satellite building.As Figure 6.8 shows, Building 100 will use two wireless out- door routers to link with the main hospital router and to Building 101 for redundancy. Data will be encrypted using 64-bit Wired Equivalent Privacy (WEP) or 128-bit RC4. This solution provides for 11 Mbps of bandwidth between the build- ings and the main hospital building, a significant increase from the 1.5 Mbps of bandwidth provided by the leased T-1 lines.Also, the hospital IS team will reduce costs by eliminating the monthly recurring costs for the leased lines. Let’s now look at how to add redundant links to provide backup connectivity in case of link or device failure. As shown in Figure 6.9, the www.syngress.com Figure 6.8 Router to Router Wireless Connectivity Main Hospital Router To Building 100 To Building 101 To Main Hospital To Building 301 To Building 300 To Building 201 To Building 200 To Building 101 Building 100 Router 11 Mbps link 152_wan_06 6/21/01 3:24 PM Page 222 [...]... wired network with the proposed wireless network www.syngress.com 152_wan_ 07 6/21/01 3:25 PM Page 235 Designing a Wireless Industrial Network: Retail Case Study • Chapter 7 Applying Wireless Technology in an Industrial Network In the past two years, companies like 3Com Corporation have designed wireless cellular digital packet data (CDPD) networks for consumer applications on popular personal digital assistants... methods used are DES, 64- bit WEP, and 128-bit RC4 Also, MAC address-based access control table schemes are used Q: What are the ranges of wireless devices outdoors? A: Directional antennas can provide a range of up to 16 miles Q: What routing or bridging functionality is available on access point devices? A: Access point wireless devices can act as bridges or routers.They can be configured with static routers... Routing Information Protocol (RIP).They can also be configured to filter based on a MAC address when acting as a bridge Q: How will wireless laptops acquire an IP address and other IP-related information? A: When using wireless bridges, you still use your existing Dynamic Host Configuration Protocol (DHCP) servers on the network to acquire an IP address, subnet masks, default gateways, Domain Name System... 6/21/01 3:25 PM Page 2 37 Designing a Wireless Industrial Network: Retail Case Study • Chapter 7 currently is not connected to the office PCs It is a stand-alone PC with a separate software package that is not tied to the company accounting system Handheld devices will enable the employees to respond to customer pages.These devices will make it easy to assess the customers who need assistance and respond... several desktop computers, three network servers, an Ethernet switch, and a router for wide area network (WAN) and Internet access.The wireless technology that will be implemented includes handheld scanning devices and a wireless card for an existing PC We will not address data security in this case study No confidential data will be transmitted using the handheld devices.The handheld devices have the capability... 152_wan_ 07 6/21/01 3:25 PM Page 241 Designing a Wireless Industrial Network: Retail Case Study • Chapter 7 access points required for efficient transmission, as well as where to put the access points s Identify any constraints that may limit the design of the wireless network. When you identify constraints early, you have more time to work around the issues Constraints can be physical, such as no access... transmission Apply the facts regarding the size of the store and the expected user density to determine the required range of RF transmission.While planning this radius, make sure you record any overflow coverage s Plan the access point locations to take advantage of transmission coverage Make sure one or two radios are added to the access point as needed for transmission Extend the radio antennas as... the access points Figure 7. 1 illustrates the layout of the departments on the first floor of Pro Sports.The first floor contains various clothing departments, a shoe department, a baseball/soccer department, a golf department, a seasonal department, and a sunglasses department Generally, the most active of all the first-floor departments is the shoe department, which contains tennis shoes, cleats, boots, and... electrical outlets.The consumer can also mandate constraints s Conduct a walk-through to verify information on the physical map.This helps you account for any deviance from the physical map to the existing structure A deviance can occur when store improvements are not added to existing documentation.Walkthroughs also provide you with additional information For example, if there was no access to an electrical... mechanical, elevator, and communications rooms In addition, having two access points increases the range and redundancy of the wireless network We decided to pair up satellite buildings to provide redundancy for the building links.This solution was not as costly as compared to creating a full mesh of wireless links.We enabled encryption to provide data security to the wireless links.We also learned that . Placements There are several methods of placing antennas to have full coverage in a floor. Directional antennas could be placed in each of the four corners of the floor aiming at a 45-degree angle. that the packets are getting forwarded via the wireless link over the leased T-1 lines. When all six wireless links are installed and are passing traffic, install and configure the redundant links as. example involving a hospital .Wireless local area network (LAN) devices in this scenario were to help information services (IS) managers provide addi- tional functionality and services. By installing wireless