i m a wisp and i got three 120 degree sector antenna on my tower. and each sector is being separately connected to a RB 411AH. so i got three sectors and three RB411AH. and i use XR2 card in each of them.
each sector have more then 40 allowed CPE by using access list feature in mikrotik. however not more then 30 concurrent users connect to individual sector at a given time. but the quantity of customer are increasing rapidly. sometimes i notice degradation in performance.
if i replace 411AH with 433AH and just place a single XR2 in each 433AH and leave rest two mini PCI slot empty. and make no other changes in rest of the setup. then will it give me extra power to increase more customer . i m in doubt bec when i see the technical specification of 433AH then its has the same processor as RB411AH but 433AH have 128 kb of Ram while RB411 have 64 Kb of Ram.
Please Give ur suggestions.
re the three 120 degree sector antennas - how far apart are they? If you use a building roof, you should use the entire space of the roof to seporate your antennas. If you use a tower - try to get at least 30 feet. If your sector antennas are real close as in feet apart you may have a good deal of bleed-over from all APs to each other. You may want to consider blocking/shielding back-side leakage to/from your sector antennas. also - make sure your antennas are gounded
90 to 120 client connections to a single AP location is a sizeable amount of client connections.
On your AP boards - if you have 3 slots and two RF cards - skip the middle slot and then configure your two cards in the AP to use something like channel 1 & 11
Do you use queues to rate limit customer upload and downloads? It only takes one customer to hammer an AP.
Have you tested RTS/CTS (look at my postings about RTS/CTS)
On your APs, try turning off CSMA and DFS
Also - as a test - try setting all 3 APs for 6 meg and 24 meg only.
I kinda have the same issues with some of my Mikrotik APs with 100+ clients on them.