Installing Windows Small Business Server 2011 : Selecting Network Components (part 1) - Selecting an Internet Service Provider

1.1. Selecting an Internet Service Provider

Virtually all businesses want to connect their networks to the Internet, even if it is only for email access. Your network planning process should include a consideration of how much bandwidth your network needs and what Internet service provider (ISP) you will use to supply it. The ISP is the only networking component you need that takes the form of a service rather than a hardware product. The service provided by the ISP is also one of the regular network expenses that you must add to your budget.

The Internet bandwidth you need for your network is primarily for client connections. The server running Windows SBS 2011 is not designed to function as an Internet router or Internet web server, although the underlying Windows Server 2008 R2 operating system is capable of doing so. This is because the server is performing critical functions for your internal network, such as being an Active Directory Domain Services (AD DS) domain controller, and making it accessible from the Internet is a serious breach of accepted security practices.

Note:

To protect their internal networks from intrusion, small businesses that want to run websites on the Internet typically use commercial web hosting services instead of running the site from one of their internal servers.

The typical uses for the Internet connection on a small-business network are email transfers and web browsing, neither of which requires massive amounts of bandwidth. Therefore, you can roughly calculate the bandwidth you need by allocating 50 Kbps (kilobits per second) of downstream bandwidth for each simultaneous web/email user. If you plan to support remote network access using virtual private network (VPN) connections, you should allocate another 50 Kbps of upstream bandwidth per user.

Tip:

BEST PRACTICES Many types of Internet connections are asymmetrical, meaning that they have different upload and download speeds. Most broadband connections, for example, provide much more downstream bandwidth than upstream. When evaluating Internet connection services, be sure to consider your upstream as well as downstream bandwidth needs.

Using these calculations, you can assume that a Windows SBS 2011 network with 25 internal users needs approximately 1,250 Kbps (1.25 megabits per second, or Mbps). A standard broadband connection from a cable or digital subscriber line (DSL) provider can usually meet these needs. Networks with more users might require a higher-speed connection.

Tip:

Do not confuse network bandwidth speeds, which are measured in kilobits (Kb), megabits (Mb), or gigabits (Gb) per second, with the download speeds displayed by your computers, which are measured in kilobytes (KB) or megabytes (MB) per second. One byte equals 8 bits, so one kilobyte equals 8 kilobits.

While calculations such as these can give you a rough idea of how much bandwidth your network needs, the most practical method of approaching the problem is to begin by determining what types of Internet connections are available at your location. Small businesses typically use standard consumer ISPs; they generally do not have the bandwidth needs or the budget for elaborate connection technologies such as T-1 lines. In most areas, you should be able to select from the following types of providers:

• Dial-up Available anywhere there is a telephone line, dial-up connections are inexpensive but slow, with a maximum bandwidth of 56 Kbps that line quality can reduce even further.

• DSL A digital subscriber line (DSL) connection is supplied by a telephone provider using the available bandwidth on a standard telephone line. Consumer DSL connections are asymmetrical and are often available in multiple speeds that can range from 256 Kbps to 20 Mbps, for varying prices. DSL availability and reliability depends on the distance from your location to the provider’s nearest central office.

• Cable Delivered over the same private fiber optic network used for cable television services, cable-based Internet connections are asymmetrical and can often exceed DSL in their bandwidth capabilities. Typically available in two or more tiers of service, cable download speeds can reach as high as 50 Mbps.

• Satellite Similar in speed, but generally more expensive than cable or DSL, satellite Internet providers target customers in remote locations that have no access to other high-speed Internet services.

When contacting the ISPs that service your area, you should find out what connection speeds they provide and, of course, the prices. When discussing the price of a connection, be sure to consider the following points:

• Contracts Some ISPs discount the monthly connection fee if you sign a contract for a year of service or more. You might want to evaluate the service for a month or two before you commit, but the savings can be significant. Bear in mind, however, that there are penalties for early termination of the contract.

• Hardware leasing Broadband connections require a modem. In many cases, you must choose between leasing a modem from the ISP, for an additional monthly fee, and purchasing one outright. The modems are usually not expensive, and purchasing the device can often begin saving you money within one or two years.

• Networking Some ISPs have different tiers of service, and different prices, for business customers or customers who connect the service to a network rather than a single computer.

In most cases, small-business administrators decide on one of the broadband solutions available in their area. Depending on the ISP and the conditions of your site, you might have to schedule an installation, but in some cases, you can obtain a self-installation kit and connect the modem to the ISP’s network yourself.

1.2. Selecting a Router

In many ways, the key component for your network is the router because you will probably purchase a unit that combines the broadband routing function with other important networking components. The components in the router that you select often dictate what features you have to look for in your other networking equipment.

For a small-business network, a consumer-grade router that also includes firewall and network connectivity functions is usually sufficient. Business-grade products are more expensive and usually separate the routing capabilities from the other functions, forcing you to purchase individual router, switch, and wireless access point products. If you choose to purchase separate components, you must be sure that all the products you select are compatible in the networking standards and protocols that they support.

Tip:

A consumer-grade broadband router typically includes an Ethernet switch, a wireless access point, or both. In most cases, the difference in price between a unit with wireless capabilities and one without is minimal, so you might consider purchasing a broadband router with both wireless and cabled Ethernet switching capabilities, even if you do not plan to use one or the other right away.

The consumer-grade router that you choose for your network should have all or most of the following capabilities:

• Broadband connectivity The device has an Ethernet wide area network (WAN) port, which connects to your broadband modem using a standard Ethernet patch cable. A broadband client built into the unit enables you to specify the user name and password for your ISP account, as well as configure account parameters.

• Switched Ethernet ports Virtually all broadband routers have at least one switched Ethernet port, but few have more than four or five. If you intend to have more than a few cabled devices on your network, you need a separate Ethernet switch that provides a larger number of ports. The switched ports on most routers support standard 10 Mbps Ethernet (10Base-T) and 100 Mbps Fast Ethernet (100Base-TX). If you have 1,000 Mbps Gigabit Ethernet devices on your network, they automatically negotiate down to Fast Ethernet when you connect them to the switch.

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  Tip:

  If you are running a Gigabit Ethernet network with a separate switch, plugging the router into the switch establishes a connection at 100 Mbps. There is no need to search for a broadband router with Gigabit Ethernet ports because the connection between the switch and the router only carries traffic to and from the Internet, and Internet connections run at far slower speeds than local area network (LAN) connections.

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• Wireless access point Routers with wireless networking capabilities have antennas, a transceiver, and an access point that enables wireless devices to connect to the network. Virtually all of the wireless routers on the market today support the 54 Mbps IEEE 802.11g standard, but they can also support devices using the slower IEEE 802.11b and IEEE 802.11a standards. Many devices also now support the newer IEEE 802.11n standard, which can provide speeds up to 600 Mbps.

• Wireless security protocols While older wireless devices can usually connect to an IEEE 802.11g transceiver, they might not support the latest wireless security protocols. Most of the current wireless router products support the Wi-Fi Protected Access (WPA and WPA2) security protocols, while older devices might support only Wired Equivalent Privacy (WEP), which has critical weaknesses. Routers can typically use only one wireless security protocol at a time, so all your wireless devices must support the protocol that you elect to use.

• Web-based administration Broadband routers typically have an internal web server that you access to configure the device’s properties. You therefore must connect a computer to the router before you can use it to connect to your ISP’s network.

• Dynamic Host Configuration Protocol (DHCP) server Most routers include DHCP server capability, which enables them to assign Internet Protocol (IP) addresses and other Transmission Control Protocol/Internet Protocol (TCP/IP) configuration settings to clients on the network. Windows SBS 2011 also includes a DHCP server. You must decide whether you want to use DHCP to configure your client workstations, and if so, which DHCP server implementation you want to use.

• Universal Plug and Play (UPnP) UPnP is a set of protocols that enable devices on the same network to communicate and automatically configure their networking settings. Windows SBS 2011 can communicate with a UPnP router to determine what IP address it should use and open the appropriate firewall ports for the services running on the computer.

• Network Address Translation (NAT) NAT is the router technology that enables the computers on your internal network to use private IP addresses and still access the Internet. NAT also protects your network from Internet intrusion.
  

• Virtual private networking (VPN) A VPN connection is when an authenticated user at a remote location connects to the Internet and accesses your private network through your router. This enables users who are traveling or working at home to access their files, Exchange Server email, and other network resources. To enable VPN connections, the router must be able to open the appropriate port for the VPN protocol the client uses to connect to the network server.

• Access restrictions Many broadband routers enable you to specify which of the computers on your network are allowed to access the Internet, or restrict Internet access to certain days and times. These features can prevent casual intruders from accessing the Internet through your router, but they are relatively ineffective against determined and knowledgeable attackers.

• Content filtering Many broadband routers enable you to block client access to specific network services on the Internet, specific website addresses, or websites containing specific keywords. Knowledgeable users can often find ways to bypass these features, but they are reasonably effective on casual users.

• Firewall Broadband routers usually have a variety of firewall features that are designed to protect your network from various types of attacks. Features such as packet filtering and stateful packet inspection (SPI) analyze incoming traffic to limit the network’s susceptibility to specific types of attacks from the Internet.

3.2.1.3. Selecting Cables, Adapters, and Switches

If you decide to install a cabled network, you must have an Ethernet network interface adapter in each of your computers; a switch that functions as the central connection point; and, of course, the cables themselves.

1.3.1. Cables

Choosing cables is a relatively simple matter. If you plan to use prefabricated cables throughout the network, purchase Category 5 or 5e cables of appropriate lengths. The maximum length for the cable connecting an Ethernet device to the switch is 100 meters. Category 5e cable is more expensive than Category 5, and the standards do not require it, but if you are planning to run Gigabit Ethernet throughout your network, Category 5e cable is usually worth the additional expense.

If you are having bulk cable installed at your site, make sure that the contract calls for all cables and connectors to be Category 5 or 5e. You also must purchase prefabricated patch cables to connect your computers to the wall plates and your Patch panel ports to the switch. These too must be Category 5 or 5e. As with a chain, it’s important to remember that a network connection is only as strong as its weakest link.

Nearly all the desktop computers sold today have an Ethernet adapter integrated into the motherboard. Higher-end workstations and virtually all servers have 1,000 Mbps Gigabit Ethernet adapters, while some budget workstations have 100 Mbps Fast Ethernet. No matter what the maximum speed, however, most Ethernet adapters and switches can negotiate down to accommodate slower speeds. For example, if you plug a computer with a Gigabit Ethernet adapter into a Fast Ethernet switch, the two devices negotiate the fastest speed they have in common, which is 100 Mbps. Switches perform separate negotiations on each port, so it is possible to mix Ethernet devices running at different speeds on the same network.

Note:

For most network applications, 100 Mbps Fast Ethernet is more than sufficient. However, if many of the computers that you intend to purchase have integrated Gigabit Ethernet adapters, a Gigabit Ethernet switch is not that much more expensive than a Fast Ethernet one.

If you have computers with no Ethernet adapter or if you want to upgrade a computer to a faster Ethernet standard, you can purchase network interface cards (NICs) that plug into an expansion slot. Before you select NICs, be sure that each computer has a free slot and check what type of slot it is. For computers without free slots, there are external network interface adapters available, which plug into a universal serial bus (USB) port.

Higher-end adapter cards frequently have integrated network management functionality, which provides the device with the ability to report its status to a centralized Network Management console. For a small business network, this capability is not needed, so when evaluating adapters, don’t reach for the cheapest adapters in the market, but don’t buy the most expensive ones, either.

1.3.3. Switches

Apart from the Ethernet standards they support, the other main issue when purchasing a switch is the number of ports. Switches are available in a variety of sizes, with as many as 48 ports, often clustered in multiples of 8. As with computer memory or hard disk space, buying more switch ports than you think you need is usually a good idea. Having a switch with extra ports enables you to expand your network later simply by plugging additional computers or other devices into the switch.

When evaluating switches, you will notice that prices range from under US $100 to well up in the tens of thousands of dollars. For a small business, you are again more likely to be looking at lower-end, consumer-grade switches rather than high-end, enterprise network products. Some of the other features that you might encounter when shopping for a switch are as follows:

• Form factor Most small-business networks want external switches and routers; that is, freestanding devices with their own cases and power supplies. Networking devices are also available in rack-mounted form factors, which are efficient and convenient if you have a formal data center but are beyond the means of most small businesses.

• Uplink negotiation A twisted pair cable contains some wires that are dedicated to transmitting data and some that are dedicated to receiving it. For communication between two devices to occur, the transmit pins on one have to be crossed over to the receive pins on the other. Ordinarily, the switch performs this crossover. However, when you expand a network by connecting a second switch to your first one, the two crossovers cancel each other out. Older Ethernet hubs and switches have a designated uplink port, which lacks the crossover circuit, for a connection to another hub or switch. Modern switches have an uplink negotiation feature that enables all the ports to detect automatically whether they are connected to a computer or another switch and adjust the crossover circuit accordingly. This is a feature worth having, which adds little cost to the device.

• Management A managed switch, like a managed router or other network component, is a device with one or more interfaces that administrators can use to control its operation. This is a high-end, enterprise networking feature that most small-business networks do not need and cannot afford. Unmanaged switches are preferable for virtually all Windows SBS 2011 networks.

1.4. Diagramming the Network

As you decide what computers and components to purchase, you should create a diagram showing the layout of the network. Figure 1 shows a typical hybrid network for a small business with one server running Windows SBS 2011, eight workstations, and a broadband router that also contains a wireless access point. All the computers and the router are connected to an Ethernet switch.

This type of diagram is useful as a guide for building your network and as a reference, especially if you must familiarize employees or consultants with the network layout. However, this type of diagram shows only the relationships between the components; it is not a true map of your site showing the actual equipment locations. If you are opening a new office or renovating an existing one, and you have a floor plan available, you might want to create a second diagram that shows not only the exact placement of each component but also the cable runs connecting them.

Tip:

REAL WORLD If you are having a bulk cable installation performed by a contractor, you should insist on a diagram showing the locations of all the cable runs. This way, if you ever need to service or upgrade the cabling, you do not have to search for them inside walls or ceilings.