Inside Cisco IOS Software Architecture (CCIE Professional Development Series)

by Bollapragada, Vijay; White, Russ; Murphy, Curtis

• ISBN13: 9781587058165
• ISBN10: 1587058162
• Edition: 1st
• Format: Paperback
• Copyright: 2000-07-28
• Publisher: Cisco Press

Summary

An essential guide to understanding the Cisco IOS architecture In-depth coverage of Cisco's IOS Software architecture provides crucial information to: Prevent network problems and optimize performance through more efficient design and configuration Isolate and resolve network problems more quickly and easily Apply the appropriate packet switching method, such as process switching, fast switching, optimum switching, or Cisco Express Forwarding (CEF) Understand the hardware architecture, packet buffering, and packet switching processes for shared memory routers (Cisco 1600, 2500, 3600, 4000, 4500, and 4700 series) Understand the hardware architecture, packet buffering, and packet switching processes for the Cisco 7200 series routers Understand the hardware architecture, packet buffering, and packet switching processes for the Cisco 7500 series routers Understand the hardware architecture, packet buffering, and packet switching processes for the Cisco GSR 12000 series routers Further your knowledge of how IOS Software implements Quality of Service (QoS) Inside Cisco IOS Software Architectureoffers 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 Architectureprovides 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 Architecturebegins 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.

Author Biography

Curtis Murphy, CCIE #1521, is an engineer in Cisco's Serviceability Design Department in Research Triangle Park, specializing in IOS software products. He has worked in the networking industry since 1989 and at Cisco since 1994. While at Cisco, he has worked both as an IBM protocols specialist in the Technical Assistance Center and as a software engineer in IOS Software Development for mid-range and high-end routers.

Russ White, CCIE #2635, is a member of the IOS Network Protocols Deployment and Scalability Team at Cisco, where he is involved in the design and implementation of routing protocols and scalable network design.

Vijay Bollapragada, CCIE #1606, is currently a manager in the Solution Engineering team at Cisco, where he works on new world network solutions and resolves complex software and hardware problems with Cisco equipment. Vijay also teaches Cisco engineers and customers several courses, including Cisco Router Architecture, IP Multicast, Internet Quality of Service, and Internet Routing Architectures. He is also an adjunct professor in Duke University's electrical engineering department.

Table of Contents

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

Packet Switching Architecture

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

Shared Memory Routers

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

Early Cbus Routers

AGS Hardware Architecture

Packet Switching with the Cbus

Autonomous Switching

Cbus Fast Packet Memory

The Cisco 7000 Series Router

Summary

Particle-Based Systems

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

Cisco 7500 Routers

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

The Cisco Gigabit Switch Router: 12000

Hardware Architecture

Switching Fabric

Maintenance Bus

Gigabit Route Processor

Line Card

Packet Switching

Packet Switching: Engine 0 and Engine

Packet Switching: Engine 2 LC

Packet Switching: Switching Cells across Fabric

Packet Switching: Transmitting Packets

Summary

Quality of Service

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

NetFlow Switching 200

Flow Cache Maintenance

Flow Export

Router-Based Flow Aggregation Export (RBA)

Index

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