O'Reilly - Java Message Service

7.2.5 The Bottom Line
Java Message Service
IP multicast has significant network throughput benefits in a one-to-many broadcast of
information. A single multicast message to multiple recipients will always cause less
network traffic than sending the message to each recipient via a TCP connection. A
messaging vendor picks and chooses how much reliability to build on top of UDP based on
the quality of service required for the message as defined by JMS.
However, the choice is not that simple when it is applied to a deployment environment in a
messaging product. The performance advantages of IP multicasting are only viable for a
certain deployment environment. These advantages can diminish depending on the types
of messages in your application, the networking hardware at your site, the deployment
environment (intranet, extranet, internet), and the complexity of administration.
Make sure to benchmark your application carefully before making a final decision, using
the guidelines we discussed earlier in this chapter. You may be surprised at what you see.
When a JMS provider is put under heavy stress with lots of clients, there are so many other
factors involved that the speed at which network packets go across the wire is not usually a
significant factor. You may see that one vendor's implementation of messaging over IP
multicast will perform vastly differently from another's - even with the use of
nonguaranteed messaging. You may even find that one vendor's TCP-based
implementation performs better than another vendor's multicast implementation.
7.3 Security
In this section, we are only going to concern ourselves with those aspects of security that
are commonly supported by JMS providers. You need to think about three aspects of
security: authentication, authorization, and secure communication. How these aspects of
security are implemented is vendor-specific, and each vendor uses its own combination of
available technologies to authenticate, authorize, and secure communication between JMS
clients.
We will also discuss firewalls and HTTP tunneling as a solution to restrictions placed on
JMS applications by organizations.
7.3.1 Authentication
Simply put, authentication verifies the identity of the user to the messaging system; it may
also verify the identity of the server to the JMS client. The most common kind of
authentication is a login screen that requires a username and a password. This is supported
explicitly in the JMS API when a Connection is created, as well as in the JNDI API when
an InitialContext is created. JMS providers that use username/password authentication
may support either of these solutions:
Properties env = new Properties( );
env.put(Context.SECURITY_PRINCIPAL, "username");
env.put(Context.SECURITY_CREDENTIALS, "password");
TopicFactory topicFactory = jndiContext.lookup("...");
...
TopicConnection con =
topicFactory.createTopicConnection("username", "password");
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