Cisco Express Forwarding Understanding and troubleshooting CEF in Cisco routers and switches Nakia Stringfield, CCIE® No. 13451/Russ White, CCIE No. 2635/Stacia McKee How does a router switch a packet? What is the difference between routing a packet, switching a frame, and packet switching? What is the Cisco® Express Forwarding (CEF) feature referred to in Cisco documentation and commonly found in Cisco IOS® commands? CEF is a general term that describes the mechanism by which Cisco routers and Catalyst® switches packet-switch (route) frames. CEF is found in almost all Cisco routers and Catalyst switches, and understanding how CEF operates can improve the performance, scalability, and efficiency of your network. Cisco Express Forwarding demystifies the internal workings of Cisco routers and switches, making it easier for you to optimize performance and troubleshoot issues that arise in Cisco network environments. This book addresses common misconceptions about CEF and packet switching across various platforms, helping you to improve your troubleshooting skills for CEF- and non-CEF-related problems. The first part of the book provides an overview of packet-switching architectures and CEF operation and advanced features. It also covers the enhanced CEF structure and general troubleshooting. The second part of the book provides case studies that focus on the common topics that have been problematic for customers and those supporting Cisco networks. Full of practical examples and configurations, this book draws on years of experience to help you keep your Cisco networks running efficiently. Learn the key features of packet-switching architectures Understand the basics of the CEF architecture and operation Examine the enhanced CEF structure, which improves scalability Learn how to troubleshoot in software-switching environments Understand the effect of CEF on a Cisco Catalyst 6500 Supervisor 720 Configure and troubleshoot load sharing with CEF Evaluate the effect of CEF in an MPLS VPN environment Review CEF design considerations that impact scalability This book is part of the Networking Technology Series from Cisco Press®, which offers networking professionals valuable information for constructing efficient networks, understanding new technologies, and building successful careers. Category: Networking Covers: Routing and Switching

In this book, a leading expert on Cisco routing offers in-depth coverage of four key intra-domain protocols -- RIP, IGRP, OSPF, and EIGRP. Unlike other books on Cisco protocols, Alex Zinin shows you exactly what's happening inside your routers when you use these protocols -- so you can maximize your control over them, and leverage their full power. Cisco IP Routing demystifies even the most complex internals of Cisco IP routing with clear explanations, extensive visuals, and many real-world examples, configurations, and network designs. The heart of the book is its coverage of dynamic routing, starting with theory and then moving to the practical details of effective configuration. Alex Zinin also presents in-depth coverage of controlling routing by altering update flow, redistribution, and policy routing. For all network administrators, other Cisco networking professionals, and anyone preparing for Cisco's top-of-the-line CCIE exam.

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 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.

Cisco IOS 12.0 Switching Services is a comprehensive guide detailing available Cisco IOS switching alternatives. Cisco switching services range from fast switching and Netflow switching to LAN Emulation. This book describes how to configure routing between virtual LANs (VLANs) and teach how to effectively configure and implement VLANs on switches.

The definitive IS-IS reference and design guide Extensive coverage of both underlying concepts and practical applications of the IS-IS protocol Detailed explanation of how the IS-IS database works and relevant insights into the operation of the shortest path first (SPF) algorithm Comprehensive tutorial on configuring and troubleshooting IS-IS on Cisco routers Advanced information on IP network design and performance optimization strategies using IS-IS Network design case studies provide a practical perspective of various design strategies Comprehensive overview of routing and packet-switching mechanisms on modern routers A collection of IS-IS packet formats and analyzer decodes useful for mastering the nuts and bolts of the IS-IS protocol and troubleshooting complex problems Interior gateway protocols such as Intermediate System-to-Intermediate System (IS-IS) are used in conjunction with the Border Gateway Protocol (BGP) to provide robust, resilient performance and intelligent routing capabilities required in large-scale and complex internetworking environments. Despite the popularity of the IS-IS protocol, however, networking professionals have depended on router configuration manuals, protocol specifications, IETF RFCs, and drafts. Mastering IS-IS, regardless of its simplicity, has been a daunting task for many. IS-IS Network Design Solutions provides the first comprehensive coverage available on the IS-IS protocol. Networking professionals of all levels now have a single source for all the information needed to become true experts on the IS-IS protocol, particularly for IP routing applications. You will learn about the origins of the IS-IS protocol and the fundamental underlying concepts and then move to complex protocol mechanisms involving building, maintaining, and dissemination of the information found in the IS-IS database on a router. Subsequent discussions on IP network design issues include configuration and troubleshooting techniques, as well as case studies with practical design scenarios.

The second of two volumes, this is Cisco's official, complete self-study resource for the BGP, QoS, IP multicast, security, WANs, and MPLS areas of the new CCIE Routing and Switching 5.0 exam. Designed for experienced networking professionals, it covers every objective in these areas concisely and logically, with extensive teaching features designed to help retention and develop deeper insight.

Routing Protocols Companion Guide is the official supplemental textbook for the Routing Protocols course in the Cisco® Networking Academy® CCNA® Routing and Switching curriculum. This course describes the architecture, components, and operations of routers, and explains the principles of routing and routing protocols. You learn how to configure a router for basic and advanced functionality. By the end of this course, you will be able to configure and troubleshoot routers and resolve common issues with RIPv1, RIPv2, EIGRP, and OSPF in both IPv4 and IPv6 networks. The Companion Guide is designed as a portable desk reference to use anytime, anywhere to reinforce the material from the course and organize your time. The book’s features help you focus on important concepts to succeed in this course: Chapter objectives–Review core concepts by answering the focus questions listed at the beginning of each chapter. Key terms–Refer to the lists of networking vocabulary introduced and highlighted in context in each chapter. Glossary–Consult the comprehensive Glossary with more than 150 terms. Summary of Activities and Labs–Maximize your study time with this complete list of all associated practice exercises at the end of each chapter. Check Your Understanding–Evaluate your readiness with the end-of-chapter questions that match the style of questions you see in the online course quizzes. The answer key explains each answer. How To–Look for this icon to study the steps you need to learn to perform certain tasks. Interactive Activities–Reinforce your understanding of topics by doing all the exercises from the online course identified throughout the book with this icon. Videos–Watch the videos embedded within the online course. Packet Tracer Activities–Explore and visualize networking concepts using Packet Tracer exercises interspersed throughout the chapters. Hands-on Labs–Work through all the course labs and Class Activities that are included in the course and published in the separate Lab Manual.

This is a Cisco authorized, self-paced learning tool for CCNP preparation. This book teaches readers how to design, configure, maintain, and scale routed networks that are growing in size and complexity. The book covers all routing principles covered in the CCNP Implementing Cisco IP Routing course. This intermediate-level text assumes that readers have been exposed to beginner-level networking concepts contained in the CCNA (ICND1 and ICND2) certification curriculum. No previous exposure to the CCNP level subject matter is required, so the book provides a great deal of detail on the topics covered.

The all-in-one guide to the what, why, and how of modern campus network design.

A comprehensive introduction to all facets of MPLS theory and practice Helps networking professionals choose the suitable MPLS application and design for their network Provides MPLS theory and relates to basic IOS configuration examples The Fundamentals Series from Cisco Press launches the basis to readers for understanding the purpose, application, and management of technologies MPLS has emerged as the new networking layer for service providers throughout the world. For many service providers and enterprises MPLS is a way of delivering new applications on their IP networks, while consolidating data and voice networks. MPLS has grown to be the new default network layer for service providers and is finding its way into enterprise networks as well. This book focuses on the building blocks of MPLS (architecture, forwarding packets, LDP, MPLS and QoS, CEF, etc.). This book also reviews the different MPLS applications (MPLS VPN, MPLS Traffic Engineering, Carrying IPv6 over MPLS, AToM, VPLS, MPLS OAM etc.). You will get a comprehensive overview of all the aspects of MPLS, including the building blocks, its applications, troubleshooting and a perspective on the future of MPLS.