You known about Cisco’s three-layer hierarchical model for network design: core layer, distribution layer, and access layer. Once you have designed your network and have decided on the types of devices you’ll be using at each of the three layers, you must then pick a specific product for each of these devices. When choosing a networking product, consider the following:
- Is the product easy to install and support?
- Does the product provide the necessary features/functions to meet your networking requirements?
- Does the product support enough ports and offer enough backplane capacity to meet your network’s growth and bandwidth requirements?
- Is the product reliable, and can it provide redundancy?
- If it is a layer-3 device, does the product provide support for both mobile users and branch office connections?
- Can the product be easily upgraded, protecting your investment in the product?
If you are implementing a WAN solution, you should consider the following when making a choice:
- Make sure the solution is cost-effective.
- Make sure the service you want to use is available in the location where you will be installing it. Some services, such as ATM, DSL, and ISDN, are not available in all areas.
- Make sure the solution you choose provides the necessary amount of bandwidth for your user’s needs.
Remember that modem connections support up to only 53 Kbps and therefore are best for telnet, e-mail, small file transfers, and limited web browsing traffic. ISDN and Frame Relay connections up to speeds of 128 Kbps are more suitable for file transfers, Internet access, and voice traffic. Leased lines, DSL, ATM, and Frame Relay are best suited for multimedia applications, including voice and video, as well as for highbandwidth needs (greater than 128 Kbps).
Hubs
Hubs function at the physical layer and provide a logical bus structure for Ethernet; devices connected to the hub have the illusion that they are all connected to the same physical piece of wire. Devices connected to a hub are in the same collision domain, since hubs are repeaters and they repeat any physical layer signal that they receive. Cisco has many hub products, including the following: 1500 Micro Hub; 1528 10/100 Micro Hub; 100, 200, 300, and 400 Fast Hubs.
Switches
Switches function at the data link layer. They are normally used to solve bandwidth and collision problems. If you experience a heavy amount of collisions or a lot of contention for bandwidth, in today’s world, you would use a switch to solve your problem. Cisco supports different switching products, including the following: 1548 Micro Switch 10/100, Catalyst 1900 and 2800, Catalyst 2950, Catalyst 3550, Catalyst 4000, Catalyst 6×00, and Catalyst 8500 switches. Most of these switches support only a layer-2 functionality, like the Catalyst 1900, while others, such as the Catalyst 3550 switch, support bother layer-2 and layer-3. One of the things to keep in the back of your mind when choosing switches is that many of Cisco’s switches use different command-line interfaces (CLIs).
Routers
Routers are used to solve many problems, including the containment of broadcasts. Cisco has a wide range of routing products, including layer-3 switches that they support. Cisco groups these routing products into different categories, including home office, small office, branch office, and central site solutions, to better help you choose the appropriate product for your network.
For home office solutions, Cisco recommends the following products: 800, 900, 1600, and 1700 series routers. For small office solutions, Cisco recommends the 1600, 1700, and 2500 series of routers. For branch office solutions, Cisco recommends the 2600, 3600, and 3700 series routers.
For central site solutions, Cisco recommends the 3600, 3700, 7×00, and 12000 GSR routers, as well as the 5×00 access server products.Of all of the router products that I mentioned, only the 700 series does not use the same CLI when performing configuration tasks. Therefore, if you know how to configure a 2500 router, configuring the 3600 router (or any other router, for that matter) is basically the same.
- Is the product easy to install and support?
- Does the product provide the necessary features/functions to meet your networking requirements?
- Does the product support enough ports and offer enough backplane capacity to meet your network’s growth and bandwidth requirements?
- Is the product reliable, and can it provide redundancy?
- If it is a layer-3 device, does the product provide support for both mobile users and branch office connections?
- Can the product be easily upgraded, protecting your investment in the product?
If you are implementing a WAN solution, you should consider the following when making a choice:
- Make sure the solution is cost-effective.
- Make sure the service you want to use is available in the location where you will be installing it. Some services, such as ATM, DSL, and ISDN, are not available in all areas.
- Make sure the solution you choose provides the necessary amount of bandwidth for your user’s needs.
Remember that modem connections support up to only 53 Kbps and therefore are best for telnet, e-mail, small file transfers, and limited web browsing traffic. ISDN and Frame Relay connections up to speeds of 128 Kbps are more suitable for file transfers, Internet access, and voice traffic. Leased lines, DSL, ATM, and Frame Relay are best suited for multimedia applications, including voice and video, as well as for highbandwidth needs (greater than 128 Kbps).
Hubs
Hubs function at the physical layer and provide a logical bus structure for Ethernet; devices connected to the hub have the illusion that they are all connected to the same physical piece of wire. Devices connected to a hub are in the same collision domain, since hubs are repeaters and they repeat any physical layer signal that they receive. Cisco has many hub products, including the following: 1500 Micro Hub; 1528 10/100 Micro Hub; 100, 200, 300, and 400 Fast Hubs.
Switches
Switches function at the data link layer. They are normally used to solve bandwidth and collision problems. If you experience a heavy amount of collisions or a lot of contention for bandwidth, in today’s world, you would use a switch to solve your problem. Cisco supports different switching products, including the following: 1548 Micro Switch 10/100, Catalyst 1900 and 2800, Catalyst 2950, Catalyst 3550, Catalyst 4000, Catalyst 6×00, and Catalyst 8500 switches. Most of these switches support only a layer-2 functionality, like the Catalyst 1900, while others, such as the Catalyst 3550 switch, support bother layer-2 and layer-3. One of the things to keep in the back of your mind when choosing switches is that many of Cisco’s switches use different command-line interfaces (CLIs).
Routers
Routers are used to solve many problems, including the containment of broadcasts. Cisco has a wide range of routing products, including layer-3 switches that they support. Cisco groups these routing products into different categories, including home office, small office, branch office, and central site solutions, to better help you choose the appropriate product for your network.
For home office solutions, Cisco recommends the following products: 800, 900, 1600, and 1700 series routers. For small office solutions, Cisco recommends the 1600, 1700, and 2500 series of routers. For branch office solutions, Cisco recommends the 2600, 3600, and 3700 series routers.
For central site solutions, Cisco recommends the 3600, 3700, 7×00, and 12000 GSR routers, as well as the 5×00 access server products.Of all of the router products that I mentioned, only the 700 series does not use the same CLI when performing configuration tasks. Therefore, if you know how to configure a 2500 router, configuring the 3600 router (or any other router, for that matter) is basically the same.
