Inside the Standard Bindings: WSDualHttp

Index for bindings in this series:

After a few days break, the series on standard bindings continues. This week will take care of the remainder of the HTTP bindings, leaving only the MSMQ and PeerChannel bindings to talk about. WSDualHttp features the same support for Web Service protocols as the WSHttp binding, but is designed for use with duplex contracts.

Standard disclaimer:

I've cut down on the number of properties presented by eliminating duplicates between the binding settings and binding element settings. For instance, the XML reader quotas can be set on either the binding or the message encoder binding element, but I'm only going to show them on the message encoder. I've also omitted most of the security credential settings because they're very messy and you hopefully won't need to change them much.

Unlike WSHttp, WSDualHttp only supports SOAP security. I'll start off with the settings when no security is being used. The other two big differences you'll see between WSHttp and WSDualHttp is that the dual variety makes Reliable Messaging mandatory and adds a CompositeDuplex binding element to provide the duplex shape.

  1. System.ServiceModel.Channels.TransactionFlowBindingElement

     TransactionProtocol: WSAtomicTransactions
  2. System.ServiceModel.Channels.ReliableSessionBindingElement

     AcknowledgementInterval: 00:00:00.2000000
    EnableFlowControl: True
    InactivityTimeout: 00:10:00
    MaxPendingChannels: 128
    MaxRetryCount: 8
    MaxTransferWindowSize: 32
    Ordered: True
  3. System.ServiceModel.Channels.CompositeDuplexBindingElement

  4. System.ServiceModel.Channels.TextMessageEncodingBindingElement

     AddressingVersion: Addressing10 (
    MaxReadPoolSize: 64
    MaxWritePoolSize: 16
      MaxArrayLength: 16384
      MaxBytesPerRead: 4096
      MaxDepth: 32
      MaxNameTableCharCount: 16384
      MaxStringContentLength: 8192
  5. System.ServiceModel.Channels.HttpTransportBindingElement

     AllowCookies: False
    AuthenticationScheme: Anonymous
    BypassProxyOnLocal: False
    HostNameComparisonMode: StrongWildcard
    ManualAddressing: False
    MappingMode: SoapWithWSAddressing
    MaxBufferPoolSize: 524288
    MaxBufferSize: 65536
    MaxReceivedMessageSize: 65536
    ProxyAuthenticationScheme: Anonymous
    Scheme: http
    TransferMode: Buffered
    UnsafeConnectionNtlmAuthentication: False
    UseDefaultWebProxy: True

The CompositeDuplex element creates the back channel from the server to the client using the base address setting. Most configuration settings are unchanged from the ones used with the WSHttp binding except that there is no longer a switch to disable reliable sessions.

 CloseTimeout: 00:01:00
EnvelopeVersion: Soap12 (
OpenTimeout: 00:01:00
ReceiveTimeout: 00:01:00
SendTimeout: 00:01:00
TextEncoding: System.Text.UTF8Encoding
TransactionFlow: False

Setting the Security.Mode to Message makes exactly the same transformation as we've seen with the other standard bindings.

  1. System.ServiceModel.Channels.TransactionFlowBindingElement
  2. System.ServiceModel.Channels.ReliableSessionBindingElement
  3. System.ServiceModel.Channels.SymmetricSecurityBindingElement
  4. System.ServiceModel.Channels.CompositeDuplexBindingElement
  5. System.ServiceModel.Channels.TextMessageEncodingBindingElement
  6. System.ServiceModel.Channels.HttpTransportBindingElement

The same holds true for changing the message encoding to use MTOM.

  1. System.ServiceModel.Channels.TransactionFlowBindingElement
  2. System.ServiceModel.Channels.ReliableSessionBindingElement
  3. System.ServiceModel.Channels.CompositeDuplexBindingElement
  4. System.ServiceModel.Channels.MtomMessageEncodingBindingElement
  5. System.ServiceModel.Channels.HttpTransportBindingElement

Next time: Inside the Standard Bindings: WSFederationHttp