Perhaps I've missed it amidst the wealth of documentation here, but has anyone seen any sort of documentation which compares & contrasts the different Cisco routers? I'm looking to find:
1. What IOS's work and don't work with what router models
2. What functionality the different models encompass, including the enhancements and add-on modules available.
3. Cisco recommendations regarding appropriate usage of the different models.
4. Any component interopability (modules, memory, etc) among different models.
5. Particular strengths/weaknesses of the different models, both old and new.
Anyone seen anything like that, either on the Cisco site or elsewhere? I'd Really, Really appreciate hearing from you if you have!
Here is your starting point. http://www.cisco.com/en/US/products/hw/routers/
You have have to dig through it a bit to find some data sheets that has the comparisons, but it is there.
Each series of routers will have a general data sheet to describe different model features within that series. A series is defined by a major model number, such as 1900 series, 2900 series, 3900 series, etc. Here are some examples of documents that you find by looking on Cisco.com under Routers:
Here is a sheet detailing the ISR G2 platform in general: http://www.cisco.com/en/US/prod/collateral/routers/ps10538/aag_c45_556315.pdf
Sheet with detailed module support on the ISR G2 platform: http://www.cisco.com/en/US/prod/collateral/routers/ps10538/aag_c07_563807.pdf
1900 series data sheet: http://www.cisco.com/en/US/prod/collateral/routers/ps10538/data_sheet_c78_556319.html
It's a lot of reading, and that is only a small sample. Here is a hard copy that tries to keep up to date about most of their major products: https://cisco.mediuscorp.com/market/cisco/productView.se.work?/nxt/rcrs/proieidentity/=17787
It's not as up to date as their websites, but it is a good guide to give you the overview for devices to point you in the right direction. Great as a quick reference guide, which is it's primary goal.
Half the difficulty about hardware is knowing all of their capabilities and when to deploy what kind of hardware. I spend hours each week reading about new hardware platforms and I still am far from an expert on Cisco hardware. It's a constant process.