redirect based on uri

That looks like a good start. I think your switch statement is slightly off though. Are you ever seeing traffic go to any but the default pool?

I think {v1} would be evalutated as a literal string of v1, not the variable value for $v1. Regardless, you can avoid using the variable altogether.

switch [URI::query [HTTP::uri] "lbsc"] {
   "" {
      pool MIS-WEB50-DM
   }
   "c" {
      pool MIS-WEB50C
   }
   "d" {
      pool MIS-WEB50D
   }
   "e" {
      pool MIS-WEB50E
   }
   "f" {
      pool MIS-WEB50F
   }
   default {
      pool MIS-WEB50-DM
   }
}

If most of your requests won't have the lbsc parameter set, you could have the first test in the switch be "".

Aaron