TABLE OF CONTENTS In this IPS implementation scenario, each line card has its own control processor (see Figure 8.7). The control processors on the line cards communicate with each other through a control interface on the backplane such as PCI or Fast Ethernet. There is no single control card. Instead, the control function is distributed among the control processors on the line cards. For simplicity, the management interface is present on one of the line cards, so there is a master agent on the line card and subagents on other line cards. Management PDUs are routed to the line card with the master agent.
Each of the control processors runs the complete set of routing protocols. They communicate over the control interface with each other, so they effectively look like multiple routers in a box, with the backplane control interface acting like a LAN. So the control cards actually run the routing protocols over the backplane LAN. Since the routing functionality is now distributed, the control processors are not as heavily loaded as a single control card.
Using Figure 8.7 as an example, assume that the SNMP agent is located on Line Card 3, and the external manager communicates with the router on Line Card 1. Also, assume the variable value requested by the SNMP manager is obtained from Line Card 2. The SNMP packet is forwarded by Line Card 1 over the control backplane to Line Card 3. The SNMP agent on Line Card 3...
