Sun Microsystems 2.1 manual Server Management, Push Model

1.6Server Management

An SNMP agent is provided is provided with the Sun MediaCenter software. This agent includes the following MIB information:

■current number of playing streams;

■current aggregate bandwidth;

■number of missed deadlines;

■number and location of disk errors.

The SNMP agent also supports the following traps:

■Missed_Deadline

■Admission_Failed

■Disk_Failure

See Appendix A for a description of and instructions for configuring the SNMP agent.

1.7Push Model

The Sun MediaCenter server implements the “push” model of bit stream delivery. In this model, the server initiates and delivers bit streams over a network interface dedicated to video output. On this interface, there is no “back channel” for decoder- to-server flow control. The burden of staying within the time constraints of bit streams is entirely on the server. On the receiving end, the decoder must be fast enough to keep up with the server, but does not bear any responsibility for maintaining timely delivery.

The push model differs from the “pull” model, in which the receiving device engages a video server in a protocol for connection setup and bit-stream delivery. Both server and receiver must be able to look inside the bit stream to interpret and, possibly, take action, based on the contents of MPEG packets.

The push model has an advantage over the pull model in that receiving devices do not require intelligence for communicating with the server. Receiving devices can be simpler and less expensive than pull-model receivers.

Consistent with the push model, the Sun MediaCenter server’s supporting software, including the MSM, reflects the one-way communication between the server and receiving devices. For example, network interface drivers used for bit stream

Chapter 1 Introduction 1-11