we have two floors of office. on the first flr, we had laid CAT 5 cable a few yrs ago. WE have now laid CAT6 on the 2nd floor. our network currently is on CAT5 i.e. first floor. should it remain there or is it bettwe to shift the network (the hub, switches etc) to CAT 6 i.e 2nd floor. A lot of people tell me that it is wise to shift the entire network to the 2nd floor as flowing from CAT6 to CAT5 is better while flowing upstream from CAT5 to CAT6 could result in performance issues. please advice.
Your connection will only run as fast as your slowest cable. Although your cat6 can run gbit and more, it will only be running at a CAT 5 speed.
This will be the case if your routers and switches are connected through CAT 5. From there if you are connecting from your switch to the workstations through CAT 6, it will be useless. Still CAT 5 speed.
If your routers and switches are connected with CAT 6 and then go to the statiosn through CAT 5, it will still be CAT 5 Speed as well.
It also depends on what your routers and switches are rated for. If you don't have gigabit switches, just fastethernet. You won't get your money's worth in LAN bandwidth using CAT 6 cable.
My official reccomendation: Go 100% CAT 5e. it is cheap, runs 100% fastethernet, and will run at gigabit speeds in optimal conditions. 1000x easier to install than CAT 6 (I hate the little splitter in the middle of the cables). I have bought a 1000 foot box of CAT 5e for a little over $100, and if its a good day, you can get it cheaper than $100.
Cat6 isn't really more expensive than Cat5e anymore, so that's not really an issue. Cat6 also supports 10Gbit, so you won't need to re-do all your Cat5e runs in a decade when people are switching to 10Gbit. Cat6 is a bit irritating to run, but not as irritating as running Cat5e, then running Cat6/Cat6e again in the future.