Explanation/Reference:
Explanation:
FABRIKAM ARE A DIFFICULT SET OF QUESTIONS.
DAG NETWORKS
A DAG network is a collection of one or more subnets used for either replication traffic or MAPI traffic.
Each DAG contains a maximum of one MAPI network and zero or more replication networks.
In a single network adapter configuration, the network is used for both MAPI and replication traffic.
Although a single network adapter and path is supported, we recommend that each DAG have a minimum of two DAG networks. In a two-network configuration, one network is typically dedicated for replication traffic, and the other network is used primarily for MAPI traffic. You can also add network adapters to each DAG member and configure additional DAG networks as replication networks.
MAPI
Messaging Application Programming Interface (MAPI) is a messaging architecture and a Component Object Model based API for Microsoft Windows. MAPI allows client programs to become (e-mail) messaging-enabled, -aware, or -based by calling MAPI subsystem routines that interface with certain messaging servers. While MAPI is designed to be independent of the protocol, it is usually used with MAPI/RPC, the proprietary protocol that Microsoft Outlook uses to communicate with Microsoft Exchange.
Simple MAPI is a subset of 12 functions which enable developers to add basic messaging functionality.
Extended MAPI allows complete control over the messaging system on the client computer, creation and management of messages, management of the client mailbox, service providers, and so forth. Simple MAPI ships with Microsoft Windows as part of Outlook Express/Windows Mail while the full Extended MAPI ships with Office Outlook and Exchange.
In addition to the Extended MAPI client interface, programming calls can be made indirectly through the Simple MAPI API client interface, through the Common Messaging Calls (CMC) API client interface, or by the objectbased CDO Library interface. These three methods are easier to use and designed for less complex messaging-enabled and -aware applications. (Simple MAPI and CMC were removed from Exchange 2003.)
CONFIGURING DAG NETWORKS
There are several items to keep in mind when configuring DAG networks:
There must be one MAPI network. If there is not going to be a replication network, the MAPI network will be used for replication.
Replication networks are optional. There can be multiple replication networks.
If the replication network fails, the DAG will fail back to the MAPI network for replication.
If you want to utilize a replication network, it must reside on a different subnet than the MAPI network.
This often makes it difficult to use a replication network when building a DAG across multiple locations.
The reason being that multiple WAN connections would be needed in order to separate the MAPI traffic from the replication traffic. (After all, creating multiple VLANs within a single WAN connection defeats the purpose of creating a replication network since both networks would be sharing the same bandwidth.) Each server within a DAG must have the same number of replication networks. This means that you cannot use a replication network between two local Mailbox servers and not use a replication network for a server that is a member of the same DAG located across a WAN connection.
STEPS
1. DAGNET1 must be ReplicationEnabled
2. DAGNET2 must be MapiAccessEnabled to fulfil the requirements
Managing Database Availability Groups: Exchange 2013 Help