Multicast Address Format Names
Applies To: Windows 10, Windows 7, Windows 8, Windows 8.1, Windows Server 2008, Windows Server 2008 R2, Windows Server 2012, Windows Server 2012 R2, Windows Server Technical Preview, Windows Vista
You can use multicast address format names (introduced in MSMQ 3.0) to reference multiple destination queues when performing the following operations:
To send messages to multiple destinations (multicast format names cannot be used to read messages in a queue). When sending messages, the message is sent to every queue associated with the specified multicast address. For information on associating a queue with a multicast address using API function calls, see PROPID_Q_MULTICAST_ADDRESS, and for information on associating a queue with a multicast address using COM components, see MSMQQueueInfo.MulticastAddress.
To specify multiple response queues in PROPID_M_RESP_FORMAT_NAME or MSMQMessage.ResponseDestination when requesting response messages.
Messages cannot be sent to a multicast address within a transaction, that is, transactional messages cannot be sent to a multicast address.
Messages sent to multicast addresses cannot be encrypted by Message Queuing.
An application running on a computer that is not connected to a network can send messages to a multicast address. The messages are stored in an outgoing queue until the computer comes back online. If recoverable messaging is requested, the messages in the outgoing queue are stored on disk until they can be transmitted.
Multicast Address Format Name Syntax
The following is the general form of a multicast address format name.
MULTICAST=<Address>:<port>
IP multicast addresses must be in the class D range from 224.0.0.0 to 239.255.255.255, which corresponds to setting the first four high-order bits equal to 1110. However, only certain ranges of addresses in this range are unreserved and available for sending multicast messages. For the latest list of reserved multicast addresses, see the Internet Assigned Number Authority (IANA) Internet Multicast Addresses Web page. There are no restrictions on the port number.
Note
Message Queuing does not support IP addresses with leading zeros. For example, the address 224.0.2.063 is not supported and must be changed to 224.0.2.63. Please keep this in mind if you copy and paste any IP addresses from the preceding Web page into your code.
Note
If several source computers are sending multicast messages and you want a specific queue to receive messages from only one source computer, each source computer must send messages to a different combination of an IP address and a port number.
| For information on | See |
|---|---|
| Sending messages to multiple queues using multicast addresses | Multicast Addresses in Multiple-Destination Messaging |
| Associating a queue with a multicast address | PROPID_Q_MULTICAST_ADDRESS MSMQQueueInfo.MulticastAddress |
| Specifying multiple response queues | PROPID_M_RESP_FORMAT_NAME MSMQMessage.ResponseDestination |
| Ways to obtain a format name | Obtaining Format Names |
| The elements and syntax of public format names | Public Format Names |
| The elements and syntax of private format names | Private Format Names |
| The elements and syntax of multiple-element format names | Multiple-Element Format Names |
| The elements and syntax of direct format names | Direct Format Names |
| The elements and syntax of machine and connector format names | Machine and Connector Format Names |
| Using IP multicast addresses to send messages | Sending Messages to Multiple Destination Examples |