Cisco Cisco Configuration Engine 3.5.3 开发者指南

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Cisco Configuration Engine Software Development Kit API Reference and Programmer Guide 3.5.3
OL-17661-04
Chapter 2      Event Service and IMGW
Event Service Overview
Each Cisco IOS device maintains a permanent Transmission Control Protocol (TCP) connection with the 
Event Gateway. The Event Gateway and the TIB/Rendezvous daemon only reside on the host system. 
Every event message passes through the TIB/Rendezvous daemon. The TIB/Rendezvous daemon 
dispatches messages to subscribers, posts messages to the TIB/Rendezvous network, filters 
subject-addressed messages, and guarantees packet delivery. 
As shown in 
, a device can either be a producer, a consumer, or both. Producer and consumer 
applications can be running on IOS, Solaris version 2.10.
Event Services Structure
The network devices open one TCP session per device to the Event Gateway as shown in 
. For 
every session on the TCP pipe, the gateway opens a Rendezvous transport to the TIB/Rendezvous 
daemon through the TIBCO API interface. Requests to register and unregister consumers, requests to 
post events, and event notification happen through the gateway, which acts as an interface between the 
devices and the Rendezvous daemon.
Figure 2-2
Event Services 
The TIB/Rendezvous daemon is responsible for passing messages between the Rendezvous transports. 
The Rendezvous routing daemon (rvrd) is used for routing messages across subnets. 
When a TCP session is severed, the gateway terminates the corresponding Rendezvous transport. The 
termination of the transport leads to the clearing of resources allocated for that transport in the daemon. 
An advisory message will then be sent to notify that the terminated transport is no longer valid.
The termination of a transport might lead to a subscription path being removed, if that transport was the 
only listener for a particular subject. This prevents a message with that subject name from being placed 
on the event bus.
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TCP
TCP
TCP
TCP
Network
devices
Gate
w
a
y
CNS Ev
ent Bus
TIB
TIB/Rendezvous
rv transport
rv transport
rv transport
rv transport