We run a 9 site network with MX84 or MX100 HA pairs at each edge site and an MX250 pair in the primary DC. Edge MXs are in routed mode with two WAN links and core MXs are in concentrator mode meaning you can have more than 2 links as they are terminated in a L3 switch. The primary CUCM server is at the main DC and we have about 5-600 handsets.
Using the built in best for VoIP QoS rule we get perfect voice calls but sometimes the CUCM desk video calls aren't perfect. I was going to try the no-NAT feature on the 15.x MX train but while talking it through I can't see how that would make any difference as the auto VPN builds the tunnel to be LAN-LAN. Perhaps I'm wrong though?
We load balance all other traffic and have created a low latency rule to shove latency sensitive traffic down the best path dynamically and in combination with the built in rule is seems excellent.
All in all I'm very impressed how you can make realtime changes very easily and not only does it show the effects pretty much instantly with good graphs and flow logs, it doesn't disrupt ongoing traffic that you aren't selecting.
A** Meraki
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