Introduction to Event Notification

Definition of a Trap

Each CA, router, and switch contains the following management agents:

• Implementation of the SMA, PMA, and BMA is required.

• Implementation of the DMA, SNMP tunneling agent, Vendor-specific agent, and Application-specific agents is optional.

When an asynchronous, exceptional condition associated with one of the implemented management agents occurs, that agent may wish to send an event notice to its respective GSM.

It does this by issuing a Trap(Notice) MAD wherein the Notice attribute indicates the event of interest. Table 9-3 on page 178 describes the contents of the Notice attribute that is returned in the Data field of the Trap MAD.

Table 9-3. Notice Attribute Format

Field Name	Description
IsGeneric	If set to 1, the notice is generic. Otherwise it is a vendor-specific notice.
Type	7 bits. Indicates the type of event: 00h. Fatal 01h. Urgent 02h. Security 03h. Subnet Management 04h. Informational 05h-7Eh. Reserved 7Fh. Empty notice. All other fields are meaningless.
NodeType or VendorID	24 bits. If IsGeneric = 1, indicates the device type: - 000000h. Reserved. - 000001h. Channel Adapter - 000002h. Switch - 000003h. Router - 000004h. Subnet Management - 000005h-FFFFFFh. Reserved If IsGeneric = 0, indicates the 24-bit IEEE-assigned vendor ID.
TrapNumber/DeviceID	If IsGeneric = 1, indicates a class-defined trap number. FFFFh is reserved. For a description of the trap types for each management class, refer to: - Traps generated by a device's SMA and delivered to the SM are covered in “SM Traps” on page 845. - Traps generated by a device's BMA (Baseboard Management Agent) and delivered to the BM are covered in “BM-related Traps” on page 1017. - Traps generated by a device's DMA (Device Management Agent) and delivered to the DM are covered in “Device Management” on page 1117. - Traps generated by a device's PMA (Performance Management Agent) and delivered to the PM are covered in “Performance Management” on page 1019. - Traps generated by a device's VMA (Vendor-specific Management Agent) and delivered to the VM are not covered in this edition of the book. - Traps generated by a device's AMA (Application-specific Management Agent) and delivered to the AM are not covered in this edition of the book. If IsGeneric = 0, indicates Device ID assigned by vendor.
IssuerLID	16 bits. LID of the port that transmitted the trap.
NoticeToggle	1 bit. If the Notice attribute was read using a Get(Notice) rather than delivered in a Trap(Notice) MAD, this bit alternates between zero and one after each Notice is cleared from the MA's Notice queue. For more information, see “Event Subscription and Event Forwarding” on page 801. Always zero in a Notice that was delivered in a Trap(Notice) MAD.
NoticeCount	When a MA isn't capable of, or is not enabled to deliver notices via the trap mechanism, it may maintain a Notice Queue to log events that may be of interest to its respective manager. In this case, this value indicates the number of notices currently queued up by this MA in this device. For more information, see “Event Subscription and Event Forwarding” on page 801.
DataDetails	If IsGeneric = 1, the content of this field is defined by the management class and the TrapNumber. If IsGeneric = 0, the meaning of this field is vendor defined.

Subscribing to GSMs for Event Notification

Introduction

Software within or behind a CA may wish to be informed when a GSM receives a Trap from a specific CA, switch, or router. This is done via the event forwarding subscription mechanism. To subscribe, the subscriber sends a Set(InformInfo) request to the class manager.

How Does the GSM Know Who the Subscriber Is?

The GSM knows who the subscriber is (and therefore who to send an event notice to) by the SLID field in the request packet.

Information Provided by Subscriber

The subscriber tells the GSM that it wishes to be notified when a Trap MAD is received from a specific port or a range of ports. The information provided to the GSM in the InformInfo attribute identifies which CA or router ports, or switch management port the subscriber is interested in. The port of interest is specified by its GID or LID. Alternatively, the subscriber can define a collection of CA, router, or switch management ports by specifying a LID address range.

The class manager responds to the Set(InformInfo) request GMP with a GetResp(InformInfo) message to confirm or deny the requested forwarding. Subscribers wishing to subscribe to event forwarding may determine which managers exist and their locations on the fabric by querying the SA.

How Does the GSM Send an Event Notice to the Subscriber?

Upon receipt of a Trap(Notice) GMP from a port, the GSM determines if anyone has subscribed to receive notices of that type from that port. If so, the GSM sends a Report(Notice) GMP to the subscriber. The subscriber, in turn, responds with a ReportResp(Notice) GMP with the same transaction ID as that issued by the class manager—in its Report(Notice) GMP—and an empty Notice attribute.

Subscribing to SA for Event Notification

Software within or behind a CA may wish to be informed when the SA receives a Trap from a specific CA, switch, or router.

The SA implements four methods to support subscription capability:

• SubnAdmInform() is used to subscribe/unsubscribe.

• SubnAdmInformResp() is the subscription request response.

• SubnAdmReport(Notice) is used to deliver an event notice to a subscriber.

• SubnAdmReportResp() is the subscriber's response to an event notice.