Peter, 3) Which routers should be used. The options are 3com NB-II's DPE+ (dual CPU), Cisco 7200 series, or Cisco 7500 (each router will have at least two 100Base-T LAN ports). If you are going to use Cisco which is a good choice, do not go cheap and get a 7200 for the job. A 7200 can only handle three fast ethernet ports. I would look at the 7500 series or possibly there gigabit router series. That will give you enough muscle to handle the job. I would call in your local Cisco office to check out which model is most appropriate.
1) Bell Atlantic assures us that, because of the redundancy, we can expect 100% uptime from the OC-12. I would like feedback as to whether this is a realistic portrayal of the SONET environment.
Nobody gets 100% uptime from anything. Can't happen!
2) We have the option of using either single-mode or multi-mode fiber OC-3 connections - what factors should be considered in selecting the fiber media type.
Look at the distance, I believe multi mode is only good for a couple of miles, then you have to go single mode, which will drive your costs up. I hope this helps! Dave Greer Senior Telecomm Analyst