OT: WAN Bandwidth Aggregation

I was wondering if I could pick your brains for a second guys. When you
are designing or upgrading a WAN what do you feel is a good guideline for
deciding how much actual bandwidth you need, particularly at an aggregation
point. In the SRND for campus LANs it gives nice aggregation ratio numbers
for access --> distribution and distribution --> core but I can't find any
similar numbers for WANs as of yet.

You all know the drill, trying to justify $$$ for more WAN bandwidth and
would like to have some best practice recommendations that are black and
white to show people. One main thing is internet aggregation. At the
moment I have a bunch of remote sites that get their internet access and
WAN services over an MPLS solution. The SP provides internet access in the
MPLS cloud via a "network based firewall" solution. I am trying to
determine the proper amount of bandwidth I should ideally have at that
aggregation point and others in the network

Anybody have a resource or input on this topic?

-- 
Regards,
Joe Astorino
CCIE #24347
Blog: http://astorinonetworks.com
"He not busy being born is busy dying" - Dylan
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