Cover
Half Title
Title Page
Copyright Page
Table of Contents
Preface
Author
Chapter 1: Introduction to IP Routing Protocols
1.1 Why We Need Routing Protocols
1.2 Routing Methods
1.2.1 Directly Connected Interface
1.2.2 Static Routing
1.2.3 Default Routing
1.2.3.1 Default Route for an IP Host
1.2.3.2 Default Route in a Router
1.2.4 Dynamic Routing Protocols
1.2.4.1 Routing Updates
1.2.4.2 Periodic Versus Triggered Routing Updates
1.2.4.3 Routing Information Authentication
1.2.4.4 Routing Information and Network Convergence
1.3 Autonomous System
1.3.1 What Is a Network Prefix and a Route?
1.3.2 Autonomous System Numbers (ASNs)
1.3.3 Multiple Routing Domains in an Autonomous System
1.3.4 Types of Autonomous Systems
1.4 Routing Metrics and Costs
1.4.1 Hop Count
1.4.1.1 Network Diameter: Maximum Hop Count
1.4.1.2 βInfinityβ Hop Count as a Signaling Mechanism for Network Failures
1.4.1.3 Limitations of the Hop Count as a Routing Metric
1.4.2 Bandwidth
1.4.3 Delay
1.4.4 Traffic Load
1.4.5 Reliability
1.4.6 Cost
1.4.6.1 Example: OSPF Cost
1.4.6.2 Cost Based on Interface Bandwidth
1.5 Classification of Routing Protocols
1.5.1 Interior Versus Exterior Routing Protocols
1.6 Least-Cost Routing
Review Questions
References
Chapter 2: Types of Dynamic Routing Protocols
2.1 Introduction
2.2 Distance-Vector Routing Protocols
2.2.1 Basic Characteristics of Distance-Vector Routing Protocols
2.2.2 Distance-Vector Routing Protocol Operations
2.2.3 What Is a Rooting Loop?
2.2.4 Routing Loops and Workarounds β Enhancing the Performance of Distance-Vector Routing Protocols
2.2.4.1 Initial Full Routing Table Update and Periodic Updates
2.2.4.1.1 Sending Asynchronous Routing Updates
2.2.4.2 Route Maintenance and Invalidation Timers
2.2.4.2.1 Route Update Timer
2.2.4.2.2 Route Invalid Timer
2.2.4.2.3 Route Flush Timer
2.2.4.3 Holddown Timers
2.2.4.3.1 How Holddown Timers are Used
2.2.4.4 Triggered Updates
2.2.4.5 Count-to-Infinity (Maximum Hop Count)
2.2.4.6 Poison Reverse
2.2.4.7 Split Horizon
2.3 Link-State Routing Protocols
2.3.1 OSPF versus IS-IS Metrics
2.3.2 Basic Characteristics of Link-State Routing Protocols
2.3.3 Link-State Routing Protocol Operations
2.3.3.1 Neighbor Discovery
2.3.3.2 Link-State Flooding
2.3.3.2.1 OSPF Flooding and Parameters
2.3.3.3 Link-State Database
2.3.3.4 Link-State Routing Process
2.3.3.5 Calculating the Shortest Paths and Constructing the Routing Table
2.3.3.5.1 Populating the Routing Table
2.3.3.6 Areas
2.4 Path-Vector Routing Protocols
2.4.1 Why an IGP Is Not Recommended for Routing between Routing Domains or Autonomous Systems
2.4.2 Using an EGP between Routing Domains: Path-Vector Routing Protocol
2.4.3 BGP: A Path-Vector Routing Protocol
2.4.3.1 Internal and External BGP Peering
2.4.3.2 Basic Characteristics of BGP Routes
2.4.3.3 BGP Autonomous System Path Advertisement
2.4.3.4 Loop-Free Paths within an Autonomous System
2.4.3.5 Manually Configured BGP Connections over TCP
2.4.4 BGP and Path Attributes
2.5 The IP Routing Table and Selection of Best Paths
2.5.1 Path Metrics and Routing Protocols
2.5.1.1 Equal-Cost Multipath (ECMP) Routing
2.5.2 Administrative Distance and Route Selection
2.5.2.1 Administrative Distance Use Case Example
2.5.3 Prefix Length and Longest Prefix Matching Lookup
Review Questions
References
Chapter 3: Routing and Forwarding Tables in Routing Devices
3.1 Introduction
3.2 Functional Components of an IP Router
3.2.1 IP Control Engine (or Route Processor)
3.2.2 IP Forwarding Engine
3.3 High-Level Router Architectures
3.3.1 Router Architectures with Centralized Forwarding Engine
3.3.2 Router Architecture with Multiple Centralized Forwarding Engines
3.3.3 Router Architecture with Distributed Forwarding Engines
3.3.4 Control Plane Redundancy
3.4 IP Routing and Forwarding Tables
3.4.1 Routing Table
3.4.1.1 Routing Table Entries
3.4.1.2 Routing Tables in a Router with Multiple Protocols
3.4.1.3 Types of Unicast Routing Tables
3.4.1.4 Aggregate or Summary Routes in the Routing Table
3.4.2 Forwarding Table
3.5 A Note on Layer 2 Adjacency Table
3.6 IP Forwarding Operations
3.6.1 Handling Special Addresses during Packet Forwarding
3.7 Redistributing Routing Information and Routing Metric Translation
3.7.1 The Need for Route Redistribution
3.7.2 Filtering Inbound and Outbound Routing Information
3.7.3 The Need for Routing Metric Translation
Review Questions
References
Chapter 4: Static Routes in the Routing Table
4.1 Introduction
4.2 Benefits of Dynamic Routing Protocols
4.3 Benefits of Static Routing
4.4 Configuring Dynamic Routing Versus Static Routing
4.5 Standard Static Route
4.5.1 Concept of Qualified Next Hop
4.6 Default Static Route
4.7 Summary Static Route
4.8 Floating Static Route
Review Questions
References
Chapter 5: Routing Information Protocol (RIP)
5.1 Introduction
5.2 Routing Protocols and Their Databases
5.3 RIP Overview
5.4 RIPv2 Message Format and Other Characteristics
5.4.1 RIPv2 Message Format
5.4.2 Interpreting the Address Family Identifier (AFI) Field in RIPv2
5.4.3 RIPv2 Routing Table
5.4.4 RIPv2 Timers
5.4.5 RIPv2 Request Message
5.4.6 RIPv2 Response Messages
5.4.7 Sending and Receiving RIPv2 Request and Response Messages
5.5 RIPv2 Authentication
5.5.1 Plaintext Authentication
5.5.2 Cryptographic Authentication
5.5.2.1 RIPv2 Authentication Message Generation
5.5.2.2 RIPv2 Authentication Message Reception
5.6 High-Level RIP Router Architecture, Processes, and Databases
5.6.1 The RIP Process
5.6.2 The Management Process
5.6.2.1 The Route Store Process
5.6.2.2 The Interface Manager
5.6.2.3 The Sockets Manager
5.6.2.4 The Redistribution Manager
5.6.3 The Routing Table Manager Process
5.7 Filtering Routing Updates in RIP
5.7.1 Configuration of Passive Interface to Prevent or Restrict Routing Updates
5.7.2 Filtering Routes in Incoming and Outgoing Routing Updates
5.7.2.1 Distribute-List In
5.7.2.2 Distribute-List Out
5.8 Summary of RIPv2 Features
Review Questions
References
Chapter 6: Enhanced Interior Gateway Routing Protocol (EIGRP)
6.1 Introduction
6.2 EIGRP Overview
6.3 EIGRP Concepts
6.3.1 Reliable Transport Protocol
6.3.2 Main EIGRP Databases
6.3.2.1 Neighbor Table
6.3.2.2 Topology Table
6.3.2.3 Routing Table
6.3.2.4 Other EIGRP Concepts
6.3.3 Neighbor Formation
6.4 EIGRP Message Types
6.4.1 HELLO Packets
6.4.2 UPDATE Packets
6.4.3 QUERY Packets
6.4.4 REPLY Packets
6.4.5 REQUEST Packets
6.4.6 EIGRP TLVs
6.4.7 EIGRP Flags Field
6.5 EIGRP Metrics
6.6 Feasible and Reported Distance
6.6.1 Feasible Distance
6.6.2 Reported (or Advertised) Distance
6.7 Successor and Feasible Successor
6.7.1 Successor
6.7.2 Feasible Successor
6.8 Route States: ACTIVE and PASSIVE States
6.8.1 PASSIVE State
6.8.2 ACTIVE State
6.8.3 Comments on Feasible Successors when a Route is in the PASSIVE or ACTIVE State
6.9 Feasibility Condition
6.10 EIGRP Diffusing Update Algorithm (DUAL)
6.10.1 High-Level Description of DUAL
6.10.2 Message Types Used by DUAL
6.10.3 Some Behaviors of DUAL
6.10.4 Stuck-In-Active (SIA) and the Use of SIA-QUERY and SIA-REPLY Messages
6.10.4.1 Stuck-In-Active (SIA)
6.10.4.2 SIA-QUERY
6.10.4.3 SIA-REPLY
6.11 EIGRP Neighbor Discovery and Maintenance
6.11.1 Neighbor Hold Time
6.11.2 Use of HELLO Packets
6.11.3 Use of UPDATE Packets
6.11.4 Use of QUERY Packets
6.12 Building the EIGRP Topology Table
6.12.1 Route Management
6.12.1.1 Internal Routes
6.12.1.2 External Routes
6.12.2 Use of Split Horizon and Poison Reverse
6.13 Initial Neighbor and Route Discovery
6.14 EIGRP Load Balancing
6.15 EIGRP Route Redistribution
6.16 EIGRP Route Summarization
6.16.1 Auto-Summarization
6.16.2 Manual Summarization
6.17 EIGRP Authentication
6.17.1 Simple Password Authentication
6.17.2 MD5 Authentication
6.18 High-Level EIGRP Router Architecture, Processes, and Databases
6.18.1 Neighbor Table
6.18.2 Topology Table
6.18.3 Routing Table
6.18.4 Determining Successors and Feasible Successors
6.18.5 Populating and Maintaining the Neighbor Table
6.18.5.1 Understanding the SRTT, RTO, and Q Cnt Parameters
6.18.6 Populating and Maintaining the Routing Table
6.18.7 Handling the Loss of a Route to a Network Destination
6.18.8 Handling Queries for a Route to a Network Destination
6.18.9 Note on Route States, Successors, and Feasible Successors
6.19 Summary of EIGRP Features
Review Questions
References
Chapter 7: Network Path Control and Factors That Affect Routing Table Properties
7.1 Introduction
7.2 Running Multiple Routing Protocols
7.2.1 Running Multiple Overlapping Routing Protocols
7.2.2 Running Multiple Non-Overlapping Routing Protocols
7.3 The Need for Network Path Control Tools
7.3.1 What is a Routing Policy?
7.3.2 Implementing Routing Policies
7.3.2.1 Routing Policy Control Points
7.3.2.2 Packet Filter Policy Control Points
7.3.3 Routing Policies and BGP Attribute Manipulation
7.4 What Is Policy-Based Routing (PBR)?
7.5 Route Summarization
7.5.1 Using of VLSM and CIDR
7.5.2 RIP Route Summarization
7.5.3 EIGRP Route Summarization
7.5.4 OSPF Route Summarization
7.5.5 IS-IS Route Summarization
7.5.6 Static Route Summarization
7.6 Route Redistribution
7.6.1 One-Point Route Redistribution
7.6.2 Multipoint Route Redistribution
7.7 Path Control Tools
7.7.1 The Need for Path Control Tools
7.7.2 Route Redistribution Configuration Tools
7.7.2.1 Redistributing Routes into RIP
7.7.2.2 Redistributing Routes into OSPF
7.7.2.3 Default Metric for RIP, OSPF, or BGP
7.7.2.4 Redistributing Routes into EIGRP
7.7.2.5 Default Metric for EIGRP
7.7.2.6 Redistributing Routes into BGP
7.7.2.7 Redistributing Directly Connected Networks and Static Routes into a Routing Protocol
7.7.3 Route Metric: Route Redistribution and the Seed Metric
7.7.3.1 Configuring Seed Metrics
7.7.4 Administrative Distance and Path Control
7.7.4.1 Administrative Distance as a Path Control Tool
7.7.5 Route Tagging
7.7.6 Passive Interfaces
7.7.7 Static Routes
7.7.8 Default Routes
7.7.8.1 Setting Default Routes Dynamically
7.7.8.2 Setting Default Routes Statically
7.7.8.3 Configuring Default Routes
7.7.8.4 Generating Default Routes in RIP
7.7.8.5 Generating Default Routes in EIGRP
7.7.8.6 Generating Default Routes in OSPF
7.7.8.7 Generating Default Routes in IS-IS
7.7.8.8 Generating Default Routes in BGP
7.7.9 Route Maps
7.7.9.1 Route Map Applications
7.7.9.2 Defining a Route Map
7.7.10 Distribute Lists
7.7.10.1 Filtering Incoming Routing Updates
7.7.10.2 Filtering Outgoing Routing Updates
7.7.11 Prefix Lists
7.7.12 Using Policy Based Routing (PBR) for Path Control
7.7.13 Offset Lists
7.7.14 IP Service Level Agreement (SLA) Probes
7.7.14.1 When to Use Cisco IOS IP SLA Probes
7.7.14.2 Workings of Cisco IOS IP SLA Probes
7.8 Special Focus: Path Control Tools in BGP
7.8.1 BGP Route Filtering and Path Attribute Manipulation
7.8.1.1 Identifying BGP Routes
7.8.1.2 Accepting/Rejecting BGP Routes
7.8.1.3 BGP Path Attribute Manipulation
7.8.2 BGP Route Filtering
7.8.2.1 BGP AS-Path Filter Lists
7.8.2.2 BGP Prefix Lists
7.8.2.3 BGP Distribute Lists
7.8.2.4 BGP Route Maps
7.8.3 Injecting Routing Information into BGP
7.8.3.1 Injecting Routes Statically into BGP
7.8.3.2 Injecting Routes Dynamically into BGP
7.8.3.3 Route Injection and the BGP ORIGIN Attribute
7.8.4 BGP AS-Path Prepending: AS-Path Attribute Manipulation Using Dummy Entries
7.8.5 Route Aggregation in BGP
7.8.5.1 Performing BGP Route Aggregation
7.8.5.2 Route Aggregation without AS_SET
7.8.5.3 Route Aggregation with AS_SET
7.8.5.4 Changing the BGP Attributes of an Aggregate Route
7.8.5.5 Advertising the Aggregate Route Only, while Suppressing the More-Specific Routes
7.8.5.6 Advertising the Aggregate Route Plus All of the More-Specific Routes
7.8.5.7 Advertising the Aggregate Route Plus a Subset of the More-Specific Routes
7.8.6 Default Routes in BGP
7.8.7 IGP Routes Versus BGP Routes: Looking at Backdoors Routes
7.9 Unnumbered Interfaces
7.9.1 Conserving IP Addresses with Unnumbered Interfaces
7.9.2 Configuring IP Unnumbered Interfaces
7.9.3 Limitations of IP Unnumbered Interfaces
7.9.4 Receiving Routing Updates over IP Unnumbered Interfaces
7.9.5 Forwarding IP Packets over IP Unnumbered Interfaces
7.10 Routing Protocol Timers
Review Questions
References
Index
A
B
C
D
E
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