D.1. Cisco 2511

Before purchasing a Cisco router on the second-hand market ensure that the seller has the right to sell you a license to Cisco's propietary software, named ‘IOS’. If you need to purchase a software license from Cisco then this may cost more than the used 2511 hardware.

Another hidden cost is the price of a maintenance contract with Cisco. This entitles you to hardware repair or replacement and software upgrades. The software upgrades include the IOS operating software and the boot ROMs. Third parties will also offer maintenance contracts on Cisco equipment, these contracts may be significantly cheaper.

The IOS software is stored in flash memory. Later versions of IOS are larger than earlier versions, so you may need a flash memory upgrade and a dynamic memory upgrade to run a later version of IOS. If you plan to upgrade the flash memory then be aware that the boot ROM needs to be aware of the flash memory's characteristics.[1] An old boot ROM may not load IOS from a newly-purchased flash memory DIMM. It is best to order a new boot ROM when upgrading the flash memory.

Purchasing flash memory and dynamic memory from Cisco may not be as economic as purchasing Cisco-approved memory from a third party supplier such as Kingston or MemoryX.

interface Async1
 description To Linux PC
 ip unnumbered Loopback0
 async mode interactive
 no peer default ip address

line 1
 location To Linux PC
 session-timeout 30
 no exec
 login
 modem InOut
 terminal-type vt100
 special-character-bits 8
 transport preferred none
 transport input telnet
 telnet break-on-ip
 telnet ip-on-break
 stopbits 1
 flowcontrol hardware

line vty 0 4
 location Network
 password PASSWORD
 login local
 terminal-type vt100
 transport preferred none
 transport output telnet

There is a port of Linux to the Cisco 2500 series of routers. At the time of writing it did did not support the asycnhronous ports on the Cisco 2511. The attractiveness of running Linux instead of running Cisco's IOS is that Linux can support SSH. At the time of writing Cisco were yet to release SSH on the Cisco 2500 series of routers, although a unofficial beta version has been seen.