Explains how logical connections between queue managers are established
MQe supports a method of establishing logical connections between queue managers, in order to send or receive data.
MQe clients and servers communicate over connections called client/server channels.
Standard connections, used for the client/server connection style, are unidirectional, but depend on a listener at the server, as servers cannot initiate data transfer. The client initiates the connection request and the server responds. A server can usually handle multiple incoming requests from clients. Over a standard connection, the client has access to resources on the server. If an application on the server needs synchronous access to resources on the client, a second connection is required where the roles are reversed. However, because standard connections are themselves bidirectional, messages destined for a client from its server's transmission queue, are delivered to it over the standard (client/server) connection that it initiated.
A client can be a client to multiple servers simultaneously. The client/server connection style is generally suited for use through Firewalls, because the target of the incoming connection is normally identified as being acceptable to the Firewall.
Because of the way channel security works, when a specific attribute rule is specified for a target queue, it forces the local queue manager to create an instance of the same attribute rule, examples.rules.AttributeRule and com.ibm.mqe.MQeAttributeRule are treated as the same rule. If this is not a desirable behaviour, you can specify a null rule for the target queue. In this case, com.ibm.mqe.MQeAttributeDefaultRule takes effect.
Connections can have various attributes or characteristics, such as authentication, cryptography, compression, or the transmission protocol to use. Different connections can use different characteristics. Each connection can have its own value set for each of the following attributes:
The simplest type of cryptor is MQeXorCryptor, which encrypts the data being sent by performing an exclusive-OR of the data. This encryption is not secure, but it modifies the data so that it cannot be viewed. In contrast, MQe3DESCryptor implements triple DES, a symmetric-key encryption method.
Typically, authentication only occurs when setting up the connection. All flows normally use compressors and cryptors.
MQe implements the communications protocols as a set of adapters, with one adapter for each of the supported protocols. This enables you to add new protocols.