Use legacy WindowsAzure.ServiceBus .NET framework library with AMQP 1.0


This article is for existing users of the WindowsAzure.ServiceBus package looking to switch to using AMQP within the same package. While this package will continue to receive critical bug fixes until 30 September 2026, we strongly encourage to upgrade to the new Azure.Messaging.ServiceBus package instead which is available as of November 2020 and which support AMQP by default.

On 30 September 2026, we'll retire the Azure Service Bus SDK libraries WindowsAzure.ServiceBus, Microsoft.Azure.ServiceBus, and, which don't conform to Azure SDK guidelines. We'll also end support of the SBMP protocol, so you'll no longer be able to use this protocol after 30 September 2026. Migrate to the latest Azure SDK libraries, which offer critical security updates and improved capabilities, before that date.

Although the older libraries can still be used beyond 30 September 2026, they'll no longer receive official support and updates from Microsoft. For more information, see the support retirement announcement.

By default, the WindowsAzure.ServiceBus package communicates with the Service Bus service using a dedicated SOAP-based protocol called Service Bus Messaging Protocol (SBMP). In version 2.1 support for AMQP 1.0 was added which we recommend using rather than the default protocol.

To use AMQP 1.0 instead of the default protocol requires explicit configuration on the Service Bus connection string, or in the client constructors via the TransportType option. Other than this change, application code remains unchanged when using AMQP 1.0.

There are a few API features that are not supported when using AMQP. These unsupported features are listed in the section Behavioral differences. Some of the advanced configuration settings also have a different meaning when using AMQP.

Configure connection string to use AMQP 1.0

Append your connection string with ;TransportType=Amqp to instruct the client to make its connection to Service Bus using AMQP 1.0. For example,

Endpoint=sb://[namespace];SharedAccessKeyName=RootManageSharedAccessKey;SharedAccessKey=[SAS key];TransportType=Amqp

Where namespace and SAS key are obtained from the Azure portal when you create a Service Bus namespace. For more information, see Create a Service Bus namespace using the Azure portal.

AMQP over WebSockets

To use AMQP over WebSockets, set TransportType in the connection string to AmqpWebSockets. For example: Endpoint=sb://[namespace];SharedAccessKeyName=RootManageSharedAccessKey;SharedAccessKey=[SAS key];TransportType=AmqpWebSockets.

Message serialization

When using the default protocol, the default serialization behavior of the .NET client library is to use the DataContractSerializer type to serialize a BrokeredMessage instance for transport between the client library and the Service Bus service. When using the AMQP transport mode, the client library uses the AMQP type system for serialization of the brokered message into an AMQP message. This serialization enables the message to be received and interpreted by a receiving application that is potentially running on a different platform, for example, a Java application that uses the JMS API to access Service Bus.

When you construct a BrokeredMessage instance, you can provide a .NET object as a parameter to the constructor to serve as the body of the message. For objects that can be mapped to AMQP primitive types, the body is serialized into AMQP data types. If the object cannot be directly mapped into an AMQP primitive type; that is, a custom type defined by the application, then the object is serialized using the DataContractSerializer, and the serialized bytes are sent in an AMQP data message.

To facilitate interoperability with non-.NET clients, use only .NET types that can be serialized directly into AMQP types for the body of the message. The following table details those types and the corresponding mapping to the AMQP type system.

.NET Body Object Type Mapped AMQP Type AMQP Body Section Type
bool boolean AMQP Value
byte ubyte AMQP Value
ushort ushort AMQP Value
uint uint AMQP Value
ulong ulong AMQP Value
sbyte byte AMQP Value
short short AMQP Value
int int AMQP Value
long long AMQP Value
float float AMQP Value
double double AMQP Value
decimal decimal128 AMQP Value
char char AMQP Value
DateTime timestamp AMQP Value
Guid uuid AMQP Value
byte[] binary AMQP Value
string string AMQP Value
System.Collections.IList list AMQP Value: items contained in the collection can only be those that are defined in this table.
System.Array array AMQP Value: items contained in the collection can only be those that are defined in this table.
System.Collections.IDictionary map AMQP Value: items contained in the collection can only be those that are defined in this table.Note: only String keys are supported.
Uri Described string(see the following table) AMQP Value
DateTimeOffset Described long(see the following table) AMQP Value
TimeSpan Described long(see the following) AMQP Value
Stream binary AMQP Data (may be multiple). The Data sections contain the raw bytes read from the Stream object.
Other Object binary AMQP Data (may be multiple). Contains the serialized binary of the object that uses the DataContractSerializer or a serializer supplied by the application.
.NET Type Mapped AMQP Described Type Notes
Uri <type name=”uri” class=restricted source=”string”> <descriptor name=”” /></type> Uri.AbsoluteUri
DateTimeOffset <type name=”datetime-offset” class=restricted source=”long”> <descriptor name=”” /></type> DateTimeOffset.UtcTicks
TimeSpan <type name=”timespan” class=restricted source=”long”> <descriptor name=”” /></type> TimeSpan.Ticks

Behavioral differences

There are some small differences in the behavior of the WindowsAzure.ServiceBus API when using AMQP, compared to the default protocol:

  • The OperationTimeout property is ignored.
  • MessageReceiver.Receive(TimeSpan.Zero) is implemented as MessageReceiver.Receive(TimeSpan.FromSeconds(10)).
  • Completing messages by lock tokens can only be done by the message receivers that initially received the messages.

Control AMQP protocol settings

The .NET APIs expose several settings to control the behavior of the AMQP protocol:

Next steps

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