The Healthcare Simulation Technology Specialist and Information Technology

Abstract

Nearly every device in a simulation center is now reliant upon network connectivity to allow data collection, processing, transfer, or analysis. Everything from the manikin that the students interact with, to the database server that stores scenarios and grading templates, to the telephone system and video recording and debriefing software are frequently connected to some type of network connection. Understanding how these connections are made and the hardware and software required for proper operation will allow the healthcare simulation technology specialist (HSTS) to best use, troubleshoot, and design features for simulation-based education. This chapter will define common terms, describe network components and their features, as well as introduce some innovative uses of this equipment for use in healthcare simulation.

Appendix: IP Addresses and Subnets

It is important to understand that a router will provide an allotment of IP addresses within a defined range for any designated network and across the Internet. Many understand that when a device is connected to a network, regardless of if it is hardwired or wireless, it is given an IP address (like a token) to connect to the network. Most IP addresses are in the form XXX.XXX.XXX.XXX, where each set of three Xs (called an octet) forms a number between 0 and 255 allowing for 256 (2⁸) unique numbers per octet. This is called IPv4 notation. The 256 here is actually a decimal number system representation of the eight positions of a binary number in the range of 00000000–11111111 [17].

An IP address has three components much like the country, city, and zip code of a postal address. These parts are the network part, the subnet part, and the host part (see Fig. 14.10).

Fig. 14.10

In this figure the IP address 192.168.20.105 is shown and divided into its constituent pieces. The network part (in red) identifies the location potentially globally in the Internet where a piece of information is going to or coming from. The subnet part (in blue) marks a segment within a larger network. Finally the host (in yellow) identifies the specific computer or device. The “mask” that accompanies the IP address identifies how much of the IP address is allocated to the network or subnet portion. In the example above, the network mask is /16, identifying the first two octets (11111111.11111111.00000000.00000000) or (255.255.0.0) as belonging to the network. The subnet mask is /24; this is the total of the first 16 bits from the network mask and the next 8 bits from the subnet mask totaling 24 (11111111.11111111.11111111.00000000) or (255.255.255.0). This configuration would allow only the final octet to be assigned to host devices within the subnetwork. Inside of an institution, when information is traveling across the Internet, the network mask is not used for routing, and instead the subnet mask is used to define hosts and routing of information within a network [18]

Dividing a network using a subnet can add several layers of difficulty if you are not familiar or comfortable with it. Whether you are novice, intermediate, or advanced in networking, understanding the concepts of segmenting small networks within a network is a desirable trait. Subnetting can make networks easier to manage and can improve security.

The subnet mask is intended for defining the type and number of IP addresses available for a given local network. Some default categories of subnet masks are as follows:

• Class A: 255.0.0.0

• Class B: 255.255.0.0

• Class C: 255.255.255.0

The subnetting process allows an administrator to divide a single Class A, Class B, or Class C network number into smaller portions.

Example of subnets in action:

A college offering Internet connectivity may provide two SSIDs (service set identifier) to connect to its Wi-Fi network:

• 1. College Z – Student

• 2. College Z – Guest

This is an example of subnetting. The network administrator has configured the college’s switch, which manages data flow, to route data traffic to one of two different subnetworks, to allow use by students and guests . This could be achieved by partitioning the college’s network into two subnetworks by changing the subnet mask.

A subnet mask distinguishes an IP address, by separating it into “network address” (first) and “host address” (second) portions (<network>,<host>). A subnet divides the host portion further (<network>,<subnet>,<host>). A subnet mask is a 32-bit number that is used to define the number of assignable IP addresses within a network segment. The subnet mask makes all network bits “1s” and all host bits “0s” and therefore also indicates where the network and host address portions start and end [19]. For a standard home network, the subnet mask is a class C /24 network denoted as 255.255.255.0 (see Table 14.3).

The numbers 0 and 255 (00000000 and 11111111) in the host portion are reserved for the “network ID” and “broadcast ID,” respectively, leaving only 254 possible numbers to be assigned to “hosts” (individual computers or devices on a network). The router, and the IP address assigned to it, is also called the default gateway and will occupy one additional IP address.

Example device on a class C network

• Network ID        192.168.0.0/24

• Subnet mask         255.255.255.0

• IPv4 host address       192.168.1.211

• Default gateway       192.168.1.1

• Broadcast ID        192.168.1.255

This example using a class C network means that the network can only provide 256 IP addresses. The assignable range of host addresses is from 192.168.1.2 to 192.168.0.254 plus the network, broadcast, and gateway IPs. This may seem like plenty for a standard home network; however, for a college, this would not be enough IP address to operate. Looking at Table 14.3 and the following examples, we note that changing the subnet mask can increase the number of available IP addresses on the network as shown.

College Z– Employee: (Allocating 4,096 IP addresses)

• Network ID        192.167.0.0/20

• Subnet mask         255.255.240.0

• IPv4 host address       192.167.1.201

• Default gateway       192.167.0.1

• Broadcast ID        192.168.15.255

The range of possible IP addresses in for this network is 192.167.0.2–192.167.15.254

College Z – Guest: (Allocating 65,534 IP addresses)

• Network ID        192.160.0.0/16

• Subnet mask         255.255.0.0

• IPv4 host address       192.160.2.64

• Default gateway       192.160.0.1

• Broadcast ID        192.160.255.255

The range of possible IP addresses for this network is 192.160.0.2–192.160.255.254

Subnetting is one method to partition or segment your network into smaller networks. Actually configuring a network in this manner requires a special networking switch and configuration of that switch and the devices to which it connects.

When considering simulation and the number of learners that participate in a facility, it may be suitable to create several subnets for a network infrastructure.

Examples for users and groups that could be assigned to different subnetworks :

• 1. Employees and simulation devices within the workplace to connect via wireless connections

• 2. Guests outside of the workplace to connect via wireless connections

• 3. Employees and simulation devices within the workplace to connect via a hardwired connection

• 4. Voice over IP (VoIP) Phones

• 5. Video recording system

Dividing a network into a number of subnets provides the following benefits:

• Reduces the network traffic by reducing the volume of traffic and reducing collisions by decreasing the number of hosts

• Can allow for more hosts and surpass the limitations in a local area network (LAN)

• Enables users to access a specific portion of a network, without needing to provide access to the complete network

• Allows prioritization of data over specific subnets [20]

Table 14.3 Shows the subnet classifications, subnet mask, and the number of assignable IP addresses for different types of networks including Class A, B, and C and classless inter-domain routing (CDIR). Most home networks are Class C and allow for 254 connections, but multiple differentiations are possible as seen in the table. Online calculators are commonly used to assist with planning