List of Figures

Chapter 1: Introduction

Figure 1.1: OSI Reference Model and Communication between Peers.

Figure 1.2: Layering Encapsulation for a packet in the OSI Seven Layer Mode

Figure 1.3: A typical network architecture.

Figure 1.4: Protocol Implementation and Interfaces

Figure 1.5: Players in the communications infrastructure

Chapter 2: Software Considerations in Communications Systems

Figure 2.1: Web browser and TCP/IP Implementation in Unix

Figure 2.2: Unix Host implementing IP and IPX

Figure 2.3: Stream components.

Figure 2.4: Boot sequence using ROM/Flash and RAM.

Figure 2.5: Classical planar networking architecture.

Figure 2.6: Encryption abstraction layer for an IPSec module.

Chapter 3: Software Partitioning

Figure 3.1: TCP/IP packets.

Figure 3.2: Processes and tasks.

Figure 3.3: Typical Architecture of a Layer 2 Switch.

Figure 3.4: Frame Reception and Buffer Handling

Figure 3.5: Interface between routing and IP switching tasks.

Figure 3.6: Callback function.

Figure 3.7: Implementing messaging with a message queue.

Chapter 4: Protocol Software

Figure 4.1: A Simple Protocol State Machine.

Figure 4.2: Multiple memory partitions in a communications system.

Figure 4.3: A manager–agent model.

Chapter 5: Tables and Other Data Structures

Figure 5.1: Physical & Logical Interfaces on a Frame Relay router.

Figure 5.2: Logical interface.

Figure 5.3: Hardware and protocol interface control blocks.

Figure 5.4: Array-based Allocation for PICBs.

Figure 5.5: Linked List based Allocation for PICBs.

Figure 5.6: Reference modification with table resizing.

Figure 5.6: Table access.

Chapter 6: Buffer and Timer Management

Figure 6.1: Single and Multiple Buffer Pools.

Figure 6.2: The BSD mbuf Structure.

Figure 6.3: Creating an mbuf cluster with multiple mbufs.

Figure 6.4: STREAMS buffer organization.

Figure 6.5: (a)Three and (b) Two level buffer Management Schemes.

Figure 6.6: Structures in a buffer management scheme.

Figure 6.7: Managing multiple timers.

Figure 6.8: Table based timer organization.

Figure 6.9: Differential timers.

Figure 6.10: Timer management task.

Chapter 7: Management Software

Figure 7.1: Router architecture with various management schemes.

Figure 7.2: The CLI agent.

Figure 7.3: Management Routines and Internal Events.

Figure 7.4: Saving the configuration

Chapter 8: Multi-Board Communications Software Design

Figure 8.1: Chassis design with packet + circuit switched buses.

Figure 8.2: A multiple-card rack design.

Figure 8.3: Single Control Card + Multiple Line Card Architecture.

Figure 8.4: Software Partitioning on multiboard router

Figure 8.5: Access routine and local copy scenarios.

Figure 8.6: OSPF Split Control Plane Example.

Figure 8.7: Fully distributed architecture.

Figure 8.8: Control card redundancy.

Chapter 9: Going About the Development

Figure 9.1: A simulated environment

Figure 9.2: Operating system abstraction layer

Figure 9.3: Typical development environment

Figure 9.4: ANVL test tool.