One topic that you will be tested on CCNA exams is routing. Cisco routers support both dynamic and static routing. Dynamic routing uses the so called “Dynamic Routing Protocols” (such as RIP, OSPF, EIGRP etc). Static routing requires the router administrator to manually create a route on the device for a specific destination network. Static routing is not complicated, but it’s an important topic on the CCNA exam and a valuable skill for real-world networking.

To configure a static route you need to know the destination network for which you want to create a route path, the network mask of the destination network, and either the next-hop IP address or the exit interface of your device from which you can reach that destination network. It’s vital to keep that last part in mind – you’re either configuring the IP address of the next-hop router, or the interface on the local router that will serve as the exit interface.

Router#config t
Router(config)#ip route [destination network] [destination mask] [next-hop IP or exit interface]

Example:

Destination network for which we need to create a static route: 192.168.1.0 / 24
Destination network mask: 255.255.255.0

Let’s say your local router has a serial0 interface with an IP address of 10.10.10.1/30, and the downstream router that will be the next hop will receive packets on its serial1 interface with an IP address of 10.10.10.2/30. The static route will be for packets destined for the 192.168.1.0/24 network.

Configuration:

Router(config)#ip route 192.168.1.0 255.255.255.0 10.10.10.2 (next-hop IP address)

OR

Router(config)#ip route 192.168.1.0 255.255.255.0 serial0 (local exit interface)

Finally, a default static route serves as a gateway of last resort. If there are no matches for a destination in the routing table, the default route will be used. Default routes use all zeroes for both the destination and mask, and again a next-hop IP address or local exit interface can be used.

Router(config)#ip route 0.0.0.0 0.0.0.0 10.10.10.2 (next-hop IP address)

OR

Router(config)#ip route 0.0.0.0 0.0.0.0 serial0 ( local exit interface)

IP route statements seem simple enough, but the details regarding the next-hop IP address, the local exit interface, default static routes, and the syntax of the command are vital for success on CCNA exam day and in the real world.

A few days ago I have written a post about Booting a Cisco Router from USB Flash. Related to that post and since I got some questions about the subject, it seems appropriate to add some more information about how USB Drives can be managed and used in Cisco IOS routers.

Some things to consider:

• USB interfaces are supported from IOS release 12.3 (14) T IP Base and later.
• All ISR and ISR G2 routers support USB flash drives.
• Devices that have 2 USB ports, can use both USB memory sticks simultaneously.
• You can use a USB extension cable; however USB hubs are not supported.
• The IOS version supported on the router is independent of the type of USB (i.e doesn’t matter if USB is version 1.1 or 2). The older ISRs use USB type 1.1 while the newest ISR machines use USB 2.0 types.
• After inserting the USB flash memory into the corresponding port, the IOS software automatically recognizes it and generates a message on the console as shown below:

Mar 10 09:10:20.251: %USBFLASH-5-CHANGE: usbflash1 has-been inserted!

• These routers also support the use of eTokens from Aladdin (security USB tokens).
• The USB can be used to store and read both IOS images and configuration files.
• The files stored on USB sticks are not encrypted.
• Officially, Cisco routers support only USB devices from Cisco. However, it is possible to use any USB memory stick which does not require installation of specific drivers.
• The only format supported by IOS is FAT16. NTFS file format on the USB drive is not supported yet.
• USB flash drives can be formatted from IOS before being used.

How to format a USB drive from IOS

The formatting process is relatively simple using IOS:

Router # format ?
flash: Filesystem to be formatted
usbflash1: Filesystem to be formatted

Router # format usbflash1:

Format operation may take a while. Continue? [confirm]
Format operation will destroy all data in “usbflash1:”.  Continue? [confirm]
Format: Drive communication & 1st Sector Write OK…

Format: All system sectors written. OK…
Format: Total data sectors in formatted partition: 8191435
Format: Total data bytes in formatted partition: -100952576
Format: Operation completed successfully.

Format of usbflash1 complete

From this point the USB flash drive can be used with all file system commands in the Cisco IOS.