How to Cap Your Motorola SB5120 Modem

Routers are hubs that allow many users to access the same modem.

The Motorola SB5120 is a high-speed cable modem that is often installed by Internet service providers. To cap a modem refers to limiting the speed (bandwidth) and/or usage (download/upload). Users may want to cap their modem for several reasons. Capped speeds discourage users of the modem (on the network) from downloading large files, because at slower speeds this may take longer. This is often done for public wi-fi hotspots to ensure a few users don't hog the bandwidth. Capping the usage by imposing daily, weekly or monthly data transfer quotas can reduce the bill (if you are a per-usage subscriber) and keep users on the network from downloading larger files. This can be useful for offices. Capping can be done via a router.

Things You'll Need

• Motorola SB5120 modem
• Router
• 2 Ethernet cables
• Computer

Instructions

1. Purchase a router. The router should be able to handle the requirements of the network. For example, it should provide wireless printing, local area network (LAN) file sharing, etc. The most important feature of the router is that it allows the network administrator to cap the usage.

2. Plug an Ethernet cable into the Motorola SB5120's Ethernet port.

3. Plug the other end of the Ethernet cable into the WAN port or Internet port of the router.

4. Plug in the router's power.

5. Plug another Ethernet cable into a computer. Plug the other end of this Ethernet cable into the router's first LAN port. Even if this is a wireless router, this step is necessary to set up the router.

6. Insert the install CD that came with the router. An automatic setup wizard should appear. Follow the setup wizard to configure the router.

7. Access the router's setting page. Open an internet browser and enter the router's IP address. The IP will be different for every router. The IP address will be clearly indicated in the router's install manual.

8. Enter the username and password for the router. The default password and username will be given clearly in the user's manual.

9. Access the router's setup options. The exact location of the capping options will be different for every router, but it should be under "Network Settings" or a similar menu.

10. Enable capping. The list of options will vary by router. You can cap the whole network or each individual user, and you can choose to cap at certain times. The list is extensive. Set up all the cap options you desire, and save the settings. The router is now capped.

References

• "Router Security Strategies: Securing IP Network Traffic Planes"; Gregg Schudel and David J. Smith; 2008
• "Cisco Networking for Dummies"; Ron Gilster; 2002