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Cable service has taken the U.S. by storm in the last ten years. It is fast, affordable, always on, and very reliable. A number of manufacturers are competing for the cable modem router market, including Linksys, Belkin, Netgear, D-Link, and others; they also provide routers for the SOHO (Small Office Home Office) marketplace. In general, a modem is a device that serves as the interface device between a computer (which communicates via digital ones and zeros) and some form of telecom service. Two main classifications exist in this segment, wired or wireless. In essence, a wireless router combines all the functions of a wired router but adds AP (access point) functionality to the bundle, as well as some additional software to setup wireless security, filtering, and control. Let's look at each of the major functions of cable modem routers. ISP Connection Interface. These cable routers are generally configured to work with your cable-based high-speed access. Since competition in the SOHO market for high-speed access is hot, and is projected to continue, prices will get more attractive on a "dollar per bit" rate, and you can expect that router manufacturers will continue to distribute equipment that will work on either ISP format. Cable routers terminate the ISP connection directly from the cable modem via a 100Mb Ethernet interface cable. Routing. Cable routing is the management of information across a network and involves two primary functions: 1) Establishing logical destination paths for information to use, and 2) Transmission of information "packets" along the predetermined routes. Routing tables can be either discovered or programmed, depending upon the complexity of a network. In a fully meshed network, several route choices may exist for transmission between two points. Hub. Hub functionality found in this class of cable router involves the ability for multiple devices to connect to the router at the same time. Typically 4 devices in the cable router class can connect with existing connections in either a wired (100Mb Ethernet) or wireless (802.11) fashion. Note: If more than 4 wired connections are needed, external hubs can be cascaded to add additional ports. Firewall. A Firewall is either a hardware or software-based service that restricts traffic in either direction on the network, based upon the type of traffic, its requested destination, the ports requested, or other restrictions such as MAC address. Firewall functionality is a key in securing networks that are interconnected to public networks such as the Internet, or if the network allows wireless access. Wireless Security. Wireless Security for cable modems with built-in Access Points (wireless two-way radios) is a key for securing local area network resources, and is the most often overlooked step in deploying a wireless network. Several options exist beyond the "setup CD" for controlling access to a wireless network. These options include WEP encryption (not very secure), WPA encryption (more secure), MAC address filtering (restricts access from all but specific devices), and broadcast SSID suppression (hides the wireless signal from the average user). At least one of these options should be deployed to protect network resources, but significantly higher security can be obtained by combining options together. Other Applications. Cable routers enable wired users to connect up to 4 devices to the unit, effectively sharing the ISP bandwidth equally amongst all four devices. The cable routing unit will also allow peer-to-peer connections, creating a true LAN environment, not just an ISP-sharing environment. Of course, for PC-PC connections (through the router) to work, each PC must be in the same Workgroup, they must share the same IP subnet, and must also have appropriate drive shares and access permissions established to allow the connection. The cable router acts as the "LAN traffic cop", allowing communication to\ from LAN-side devices and access to/from the WAN as well. |
Cable Modem Routers
