I've had an issue lately where one of our branch offices with around 60 employees will end up sending a 10MB email to 20 users at that facility.
The problem is that the email server itself is located at HQ across a 1.5Mbps MPLS circuit.
So what happens is the Exchange server at HQ has to send a 10MB email to 20 different users across that pipe to their cached OST file (unless I'm missing something, but that's what it appears to do on the network).
This causes serious congestion on that link until all of that traffic is transmitted.
Besides putting a mailbox server at the branch office or limiting email size, are there other ways to mitigate this?