When would you need this: When you want to perform routing between different VLANs.

Special Requirements: You have to make sure that your router support the frame tagging technology used between the switches.

When would you need this: When you are implementing a routing protocol on a large Internetwork and all the networking devices involved are Cisco devices.

Special Requirements: EIGRP is a Cisco proprietary protocol. So, either all the routers in the Internetwork must be Cisco routers, or the routers should be EIGRP capable.

When would you need this: When you want to copy IOS file from one router to another for the purposes of upgrade or install. This is usually required when you do not have a TFTP server around.

Special Requirements: The flash size of the destination router should be adequate for the new IOS file size.

When would you need this: When you want to upgrade the IOS file and you do not have TFTP of FTP servers around, so you turn to the good old console for the upgrade.

Special Requirements: The router flash size should be adequate for the new IOS image, and you should have enough RAM in the router for the operation and temporary storage of the new IOS file.

When would you need this: When you want to connect a local network to the Internet and you don’t have that much IP addresses.

Special Requirements: None.

When would you need this: When you are using a dynamic routing protocol, and have more than one path to destination networks.

Special Requirements: None

When would you need this: When using the router as a DHCP server to provide IP addresses and related information to DHCP clients.

Specials Requirements: DHCP server software is supported for these series; 800, 1000, 1400, 1600, 1700 series (support for the Cisco 1700 series was added in Cisco IOS Release 12.0[2]T), 2500, 2600, 3600, 3800, MC3810, 4000, AS5100, AS5200, AS5300, 7000, 7100, 7200, MGX 8800 with an installed Route Processor Module, 12000, uBR900, uBR7200, Catalyst 5000 family switches with an installed Route Switch Module, Catalyst 6000 family switches with an installed MultiLayer Switch Feature Card, and Catalyst 8500.

When would you need this: If your router flash, or IOS file are corrupted, you can use this procedure to install a new IOS file. Also, when you plan to upgrade your IOS file you can use this procedure.

Special Requirements: The router flash size should be enough for the new IOS file.