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.