Cross site Exchange DAG with Multiple WAN Links

1. Yes you can. Just need proper planning in the network part, different subnets, etc.

2. You can choose any network you want for that.

Thanks Rafa!  I also got some finds below from:

http://technet.microsoft.com/en-us/library/dd638104.aspx#NR

to support your points.

• Using two network adapters in each DAG member provides you with one MAPI network and one Replication network.
• Each DAG member must have the same number of networks. For example, if you plan on using a single network adapter in one DAG member, then all members of the DAG must also use a single network adapter.
• Each DAG must have no more than one MAPI network. The MAPI network must provide connectivity to other Exchange servers and other services, such as Active Directory and DNS.
• Additional Replication networks can be added, as needed. You can also prevent an individual network adapter from being a single point of failure by using network adapter teaming or similar technology. However, even when using teaming, this does not prevent the network itself from being a single point of failure.
• Each network in each DAG member server must be on its own network subnet. Each server in the DAG can be on a different subnet, but the MAPI and Replication networks must be routable and provide connectivity, such that:

Why not consider enabling ISL of your connections? That could combine links together with more capacity and resiliency and you do not need to look into detail of channel allocations.

Eddy

The links are for cross sites WAN links provided by carrier.  The situation could be added a new WAN link as the existing WAN link congestion.