In the attached diagram I have tried to make our apathy simple. I'll try to explain the diagram here and then relate my question in hope that malady becomes clearer :)
Consider this, we had one MPLS provider all over our offices and life was simple. Suddenly someone somewhere made a decision to reduce dependence on a single service provider and brought in a second MPLS Service provider leaving us techies to dump our heads in order to architect around the new scenario of connecting offices on separate MPLS clouds.
Hence, soon we'll have two MPLS circuit providers, termed in the diagram as BT and ETISALAT, or simply, provider A and B. The two routers attached to the MPLS cloud are not under our administration but would reside in our premises; we'll call it our Main converging Site A.
Both the MPLS circuits terminate in our datacenter of Site A which has a pair of Cisco 6509E with Sup 720 working at the distribution layer.
On the BT MPLS cloud and Etisalat MPLS cloud are different sets of offices and some of the times, the need of an office connected to Etisalat MPLS is to directly talk to another office on BT without having to do anything with our office or enter our internal LAN.
So what we decide is, first to optimise by placing a WAN optimiser (could be Riverbed, Cisco, Bluecoat etc.. not yet decided). Wan optimisers do not yet have the capability route the traffic neither are meant to.
Now if someone attached to Provider A needs to go to someone on Provider B bypassing Site A, I need some sort of a policy based routing somewhere. Hence I am thinking of bringing in some UTM appliance, capable of undertaking PBR. Fortinet shown in the diagram is for illustrative purposes as it yet does not do PBR either. The idea of placing a UTM there is, that way, I'll also be able to check/filter malware coming into my network from my other offices (just in case).
The question is, am I missing something here? Would this concept work? Has anyone been there done this before? What if I terminate the two links directly on my 6509s and do some MPLS related stuff?