The GSMs, GSAs, and GSIs

The General Services Managers (GSMs) were introduced in “Intro to the Managers” on page 159. Refer to Figure 32-1 on page 911. The entities involved in the general services are:

• GSM. A series of GSMs have responsibility for managing various aspects of device operation. A GSM may only have responsibility for managing the devices in a single subnet, or may have responsibility for managing the devices residing in multiple subnets.

• GSAs. The entity that a specific type of GSM communicates within a device is referred to as its respective General Services Agent (GSA). Each device implements a series of GSAs, each of them having responsibility for handling incoming requests issued by their respective GSM.

• GMPs. The GSM communicates with its respective GSA by issuing General Services Management Packets (GMPs). Like SMPs, GMPs are a form of MAD (see “GMP MADs” on page 789).

• GSI. The GSM issues GMPs using a special QP (QP1) referred to as the General Services Interface (GSI). Likewise, the GMPs are received by the GSI on a port of the destination device. The GSI uses the GMP MAD's Management Class field (see Table 28-1 on page 783) in determining to which of the device's GSAs the GMP must be delivered for processing (see Figure 32-2 on page 911).

  Figure 32-2. GSI Distributes Incoming GMPs to Destination GSA

  

• If a device implements both a GSM and the GSA associated with that GSM (as shown in the left-hand device in Figure 32-1 on this page), the GSM may send and receive GMPs with GSAs in remote devices through its local GSA, or it may communicate directly with the local GSI to do so. This is implementation-specific.