Question : questions about WAN technologies (MPLS, App Acceleration, bandwidth)

I currently have a hub & spoke network with VPN tunnels to the remote sites (using public network).  We are experiencing the typical WAN problems and a looking into two different solutions:
MPLS
Application Acceleration

Questions:
1.  If you use MPLS, would you also use an application acceleration box on top of that?

2.  Is it recommended to firewall each MPLS remote site even though it's now private?

3.  Regarding MPLS bandwidth, if the remote sites are T1's, how much bandwidth would be recommended at the hub?  Is it a one-to-one ratio?  Or if I have 4 offices with 25% bandwidth allocated to CoS1 at each site, would I need at least a T1 to guarantee peak CoS1 traffic?

4.  If the hub & spoke network is with one provider, would it be better to just have the one-time cost of app accel box since you would have an SLA with the provider? (I'm not concerned with the any-to-any of MPLS connectivity in this last question).

Thanks in advance for any feedback!

Answer : questions about WAN technologies (MPLS, App Acceleration, bandwidth)

Question 1 - that depends on what applications you are running and if they are chatty.

Question 2 - not really.  if it was on MPLS the 2 sites are not external.  you could use a firewall but not needed.

Question 3 - usually you want 2/3 of the bandwidth at the host site.  if you have 4 T1 remote sites you technically should have a 3 meg pipe at the host site.  you usually dont need a one to one ratio because all 4 sites will most probably not be transmitting at once.

Question 4 - This is the same answer as i listed for question 1.

One thing is that MPLS is expensive.  it is just basically Frame relay on steroids.  low bandwidth for a big cost.   you could technically get quickert speeds with a cable modem at each site with static addresses and business package like 8 megs down adn 2 megs up for about 300 400 bucks a months depending on the carrier.  obviously you can get a larger pipe on MPLS but the cost is big.  And yes, MPLS is dedicated bandiwdth as aopposed to the cable solution, but you have to weigh your options and primary needs.