Transport chains

Transport chains represent a network protocol stack that is used for I/O operations within an application server environment.

Transport chains are part of the channel framework function that provides a common networking service for all components, including the service integration bus component of IBM® service integration technologies, WebSphere® Secure Caching Proxy, and the high availability manager core group bridge service.

A transport chain consists of one or more types of channels, each of which supports a different type of I/O protocol, such as TCP, DCS. or HTTP. Network ports can be shared among all of the channels within a chain. The channel framework function automatically distributes a request arriving on that port to the correct I/O protocol channel for processing.

Remember: If you have a routine that issues a call to start transports during server startup, unless you have a mixed-node environment and that server is running in either a Version 6.x node, you must modify your routine to issue a call to start transport chains instead of the transports. The product issues an error message if it receives a call to start transports for a server that is not running in a Version 6.x node.

The transport chain configuration settings determine which I/O protocols are supported for that chain. Following are some of the more common types of channels. Custom channels that support requirements unique to a particular customer or environment can also be added to a transport chain.

DCS channel

Used in a WebSphere Application Server Network Deployment environment by the core group bridge service, the data replication service (DRS), and the high availability manager to transfer data, objects, or events among application servers.

HTTP inbound channel

Used to enable communication with remote servers. It implements the HTTP 1.0 and 1.1 standards and is used by other channels, such as the web container channel, to serve HTTP requests and to send HTTP specific information to servlets expecting this type of information.

HTTP inbound channels are used instead of HTTP transports to establish the request queue between a web server plug-in, and a web container in which the web modules of an application reside.

HTTP proxy inbound channel

Used to handle HTTP requests between a proxy server and application server nodes.

HTTP Tunnel channel

Used to provide client applications with persistent HTTP connections to remote hosts that are either blocked by firewalls or require an HTTP proxy server, including authentication, or both. An HTTP Tunnel channel enables the exchange of application data in the body of an HTTP request or response that is sent to or received from a remote server. An HTTP Tunnel channel also enables client-side applications to poll the remote host and to use HTTP requests to either send data from the client or to receive data from an application server. In either case, neither the client nor the application server is aware that HTTP is being used to exchange the data.

JFAP channel

Used by the Java™ Message Service (JMS) server to create connections to JMS resources on a service integration bus.

MQ channel

Used in combination with other channels, such as a TCP channel, within the confines of WebSphere MQ support to facilitate communications between a service integration bus and a WebSphere MQ client or queue manager.

ORB Service channel

Used in combination with other channels, such as a TCP channel, to handle CORBA and RMI/IIOP messages for the ORB Service. It enables clients to make requests and receive responses from servers in a network-distributed environment.

SIP channel

Used to create a bridge in the transport chain between a session initiation protocol (SIP) inbound channel, and a servlet and JavaServer Page engine.

SIP container inbound channel

Used to handle communication between the SIP inbound channel and the SIP servlet container.

SIP inbound channel

Used to handle inbound SIP requests from a remote client.

SSL channel

Used to associate an Secure Sockets Layer (SSL) configuration repertoire with the transport chain. This channel is only available when SSL support is enabled for the transport chain. An SSL configuration repertoire is defined in the administrative console, under security, on the SSL configuration repertoires > SSL configuration repertoires page.

TCP channel

Used to provide client applications with persistent connections within a Local Area Network (LAN) when a node uses transmission control protocol (TCP) to retrieve information from a network.

UDP channel

Used to provide client applications with persistent connections within a Local Area Network (LAN) when a node uses user datagram protocol (UDP) to retrieve information from a network.

Web container channel

Used to create a bridge in the transport chain between an HTTP inbound channel and a servlet and JavaServer Page (JSP) engine.