An essential guide to understanding the Cisco IOS architecture
In-depth coverage of Cisco's IOS Software architecture provides crucial information to:
Inside Cisco IOS Software Architecture offers crucial and hard-to-find information on Cisco's Internetwork Operating System (IOS) Software. IOS Software provides the means by which networking professionals configure and manage Cisco networking devices. Beyond understanding the Cisco IOS command set, comprehending what happens inside Cisco routers will help you as a network designer or engineer to perform your job more effectively. By understanding the internal operations of IOS Software, you will be able to take architectural considerations into account when designing networks and isolate problems more easily when troubleshooting networks. Inside Cisco IOS Software Architecture provides essential information on the internal aspects of IOS Software at this level, and it is an invaluable resource for better understanding the intricacies of IOS Software and how it affects your network.
Inide Cisco IOS Software Architecture begins with an overview of operating system concepts and the IOS Software infrastructure, including processes, memory management, CPU scheduling, packet buffers, and device drivers, as well as a discussion of packet switching architecture with detailed coverage of the various platform-independent switching methods, including process switching, fast switching, optimum switching, and Cisco Express Forwarding (CEF). The book then delves into the intricate details of the design and operation of platform-specific features, including the 1600, 2500, 4x00, 3600, 7200, 7500, and GSR Cisco routers. Finally, an overview of IOS Quality of Service (QoS) is provided, including descriptions of several QoS methods, such as priority queuing, custom queuing, weighted fair queuing, and modified deficit round robin.
1. Fundamental IOS Software Architecture 2
Operating Systems Basics. CPU Resource Management and Multitasking. Memory Resource Management. Interrupts. IOS Architecture Overview. Memory Organization. Memory Pools. IOS Processes. Process Life Cycle. IOS Process Priorities. Process Examples. IOS Kernel. The Scheduler. The Memory Manager. Packet Buffer Management. System Buffers. Device Drivers. Summary.
Routing 101: Process Switching. Traffic Load Sharing with Process Switching. Disadvantages of Process Switching. Fast Switching: Caching to the Rescue. Fast Cache Organization. Maintaining the Cache. Traffic Load Sharing Considerations with Fast Switching. Optimum Switching. Cisco Express Forwarding. How CEF Works. Traffic Load Sharing with CEF. Summary.
Hardware Architecture for Shared Memory Routers. CPU. Memory. Interface Controllers. Packet Buffers for Shared Memory Routers. Private Buffer Pools. Receive Rings and Transmit Rings. Packet Switching on a Shared Memory Router. Receiving the Packet. Switching the Packet. Transmitting the Packet. Summary.
AGS+ Hardware Architecture. Packet Switching with the Cbus. Autonomous Switching. Cbus Fast Packet Memory. The Cisco 7000 Series Router. Summary.
Buffer Management Using Particles. Particle Pools. Particle Coalescing. The Cisco 7200 Series Routers. Hardware Architecture. Memory. Packet Switching on the Cisco 7200 Series Routers. Packet Receive Stage. Packet Switching Stage. Packet Transmit Stage. Summary.
Hardware Architecture of the Cisco 7500 Router. The Data Bus. Route Switch Processor. Packet Switching on the Cisco 7500 Router. RSP Switching: Receiving the Packet. RSP Switching: Switching the Packet. RSP Switching: Transmitting the Packet. VIP Architecture. VIP Components. VIP Models. VIP Packet Operations: Distributed Switching. VIP Receive Side Buffering. Troubleshooting Tips for the Cisco 7500 Router. High CPU Utilization. Input Drops. Ignores. Output Drops. Summary.
Hardware Architecture. Switching Fabric. Maintenance Bus. Gigabit Route Processor. Line Card. Packet Switching. Packet Switching: Engine 0 and Engine 1. Packet Switching: Engine 2 LC. Packet Switching: Switching Cells across Fabric. Packet Switching: Transmitting Packets. Summary.
QoS Overview. Congestion Management. Congestion Avoidance. Priority Queuing. Configuring and Monitoring Priority Queuing. Custom Queuing. Weighted Fair Queuing. Platform-Independent WFQ. Configuring and Monitoring WFQ. Distributed Weighted Fair Queuing. Modified Deficit Round Robin. Configuration of MDRR. Weighted Random Early Detection. Configuration and Monitoring of WRED. Selective Packet Discard. Other QoS Features. Summary.
Flow Cache Maintenance. Flow Export. Router-Based Flow Aggregation Export (RBA).