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.
Figure D-1. Basic configuration for Cisco 2511 terminal server to Linux PC
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.
[1] | This is a fault of the design of flash memory. It identifies itself with a model designator rather than with the timings required to read and write the memory. So to load software from flash memory the boot ROM must have a table of flash memory models and timings. |