Hi,

Would you please elaborate your environment?

Did you mean ISR router to be Cisco ISR?

If yes, you can refer to link below:

http://www.microsoft.com/en-us/download/confirmation.aspx?id=28555

Best Regards,
Eason Huang

Actually, we have several remote offices (all are on same Lync 2010 central Site). These remote offices are connected with HeadQuaters across MPLS. In these remote offices there are DNS service (DC), not DHCP service. PSTN connectivity is on HeadQuarters

We want that if MPLS is down, Lync users can work without problems.

If it's a intelligent failover route, and it's ultimately abstracted from Lync, I'd think you'd be fine.  We've done this to an extent, but the paths can't be active/active because you wouldn't want some media packets arriving before others due to taking different routes. 

Any experience with "Intelligent WAN" and ISR with Lync. I think we can use ISR router to balance traffic across MPLS and Internet on Branch Office...not ??