Addressing Digit Signaling

There are two methods for submitting analog address digits to place a call Dual-tone multifrequency (DTMF) dialing Pulse dialing uses the opening and closing of a switch at the telephone set. A rotary register at the CO detects the opening and closing of the loop. When the number 5 is dialed on a rotary phone, the dial mechanism opens and closes five times, each one-tenth of a second apart. DTMF uses two tones simultaneously to indicate the dialed number. Table 15-3 shows the phone keypad and...

B

On VoIP networks, 527-528 WAN technology considerations, 169 BDRs (backup designated routers), 362-363 Beauty Things scenario, 577-579 Bellman-Ford algorithm, 295 best path selection BGP, 401 metrics, 300-301 bandwidth, 301 cost, 302-303 delay, 303 hop count, 301 load, 303 MTU, 304 reliability, 304 BGP (Border Gateway Protocol), 390 administrative distance, 396 attributes, 396 atomic aggregate, 399-400 community, 399 local preference, 397 MED, 398-399 next-hop, 397 origin, 398 weight, 400 best...

Best Practices for Hierarchical Layers

Each layer of the hierarchical architecture contains special considerations. The following sections describe best practices for each of the three layers of the hierarchical architecture access, distribution, and core. When designing the building access layer, you must take into consideration the number of users or ports required to size up the LAN switch. Connectivity speed for each host should be considered. Hosts might be connected using various technologies such as Fast Ethernet, Gigabit...

Binary Numbers

The binary number system uses two digits 1 and 0. Computer systems use binary numbers. IP addresses and MAC addresses are represented by binary numbers. The number of binary 1s or 0s is the number of bits, short for binary digits. For example, 01101010 is a binary number with 8 bits. An IP address has 32 bits, and a MAC address has 48 bits. As shown in Table B-2, IPv4 addresses are usually represented in dotted-decimal format therefore, it is helpful to know how to convert between binary and...

Campus Design Considerations

When designing for the Cisco Unified Wireless Network, you need to be able to determine how many LWAPs to place and how they will be managed with the WLCs. Table 4-4 summarizes campus design considerations. Table 4-4 WLAN Design Considerations Table 4-4 WLAN Design Considerations The design should have enough APs to provide full RF coverage for wireless clients for all the expected locations in the enterprise. Cisco recommends 20 data devices per AP and 7 g.711 concurrent or 8 g.729 concurrent...

Campus LAN Quality of Service Considerations

For the access layer of the campus LAN, you can classify and mark frames or packets to apply quality of service (QoS) policies in the distribution or at the Enterprise Edge. Classification is a fundamental building block of QoS and involves recognizing and distinguishing between different traffic streams. For example, you distinguish between HTTP HTTPS, FTP, and VoIP traffic. Without classification, all traffic would be treated the same. Marking sets certain bits in a packet or frame that has...

CCDA Official Exam Certification Guide Third Edition

Anthony Bruno, CCIE No. 2738 Steve Jordan, CCIE No. 11293 Copyright 2007 Cisco Systems, Inc. Published by Cisco Press 800 East 96th Street Indianapolis, IN 46240 USA All rights reserved. No part of this book may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage and retrieval system, without written permission from the publisher, except for the inclusion of brief quotations in a review. Printed in...

Network Design Methodology

Do I Know This Already Quiz 5 Foundation Topics 8 Intelligent Information Network and Service-Oriented Network Architecture 8 IIN Framework 8 SONA 9 Network Infrastructure Layer 10 Interactive Service Layer 11 Application Layer 11 Benefits of SONA 12 Prepare, Plan, Design, Implement, Operate, and Optimize Phases 13 Prepare Phase 14 Plan Phase 14 Design Phase 14 Implement Phase 14 Operate Phase 14 Optimize Phase 15 Design Methodology Under PPDIOO 15 Identifying Customer Requirements 15...

Traditional Voice Architectures and IP Telephony Design 497

Do I Know This Already Quiz 497 Foundation Topics 500 Traditional Voice Architectures 500 PBX and PSTN Switches 500 Local Loop and Trunks 501 Ports 503 Major Analog and Digital Signaling Types 503 Loop-Start Signaling 504 Ground-Start Signaling 504 E& M Signaling 505 CAS and CCS Signaling 506 PSTN Numbering Plan 508 Other PSTN Services 510 Centrex Services 510 Voice Mail 510 Database Services 510 IVR 510 ACD 511 Voice Terminology 511 Grade of Service 511 Erlangs 511 Centum Call Second (CCS)...

Network Structure Models

Do I Know This Already Quiz 33 Foundation Topics 36 Hierarchical Network Models 36 Benefits of the Hierarchical Model 36 Hierarchical Network Design 37 Core Layer 38 Distribution Layer 38 Access Layer 39 Hierarchical Model Examples 40 Cisco Enterprise Architecture Model 42 Enterprise Campus Module 43 Enterprise Edge Module 45 E-Commerce 45 Internet Edge 46 VPN Remote Access 47 Enterprise WAN 48 Service Provider (SP) Edge Module 49 Remote Modules 50 Enterprise Branch Module 50 Enterprise Data...

WAN Technologies 151

Do I Know This Already Quiz 151 WAN Defined 154 WAN Connection Modules 155 WAN Comparison 156 Dialup 157 ISDN 157 Frame Relay 159 Time-Division Multiplexing 160 SONET SDH 160 Multiprotocol Label Switching 161 Other WAN Technologies 162 Digital Subscriber Line 162 Cable 163 Wireless 164 Dark Fiber 166 Dense Wave Division Multiplexing 166 Ordering WAN Technology and Contracts 166 WAN Design Methodology 167 Response Time 168 Throughput 168 Reliability 168 Bandwidth Considerations 169 Window Size...

Routing Protocol Selection Criteria 289

Do I Know This Already Quiz 289 Routing Protocol Characteristics 292 Static Versus Dynamic Route Assignment 292 Interior Versus Exterior Routing Protocols 294 Distance-Vector Routing Protocols 295 EIGRP 296 Link-State Routing Protocols 296 Distance-Vector Routing Protocols Versus Link-State Protocols 297 Hierarchical Versus Flat Routing Protocols 297 Classless Versus Classful Routing Protocols 298 IPv4 Versus IPv6 Routing Protocols 299 Administrative Distance 299 Routing Protocol Metrics and...

Cisco Enterprise Architecture Model

The Cisco Enterprise Architecture model facilitates the design of larger, more scalable networks. It represents the focused views of the Cisco Service-Oriented Network Architecture (SONA), which concentrates on each area of the network. SONA is covered in Chapter 1, Network Design Methodology. As networks become more sophisticated, it is necessary to use a more modular approach to design than just WAN and LAN core, distribution, and access layers. The architecture divides the network into...

Cisco IOS Packaging

Cisco IOS packaging involves consolidating and organizing the IOS software using consistent and standardized naming across all router platforms. The four base service categories are as follows IP Base Entry-level IOS supporting IP data IP Voice Supports converged voice and data Advanced Security Security features and VPN Enterprise Base Enterprise Layer 3 protocols and IBM support In addition, three additional premium packages offer new IOS software features that focus on more complex...

Codec Standards

Codecs transform analog signals into a digital bit stream and digital signals back into analog signals. Figure 15-14 shows that an analog signal is digitized with a coder for digital transport. The decoder converts the digital signal into analog form. Each codec provides a certain quality of speech. A measure used to describe the quality of speech is the Mean Opinion Score (MOS). With MOS, a large group of listeners judges the quality of speech from 5 (best) to 1 (bad). The scores are then...

Comparing Hardware and Software

Table 6-4 compares the Cisco router and switch hardware platforms and their associated software families, releases, and functional descriptions. Table 6-4 Cisco Router Switch Platform and Software Comparison Table 6-4 Cisco Router Switch Platform and Software Comparison Cisco IOS T Releases 12.3, 12.4, 12.3T, and 12.4T Access routing platforms supporting fast and scalable delivery of data for enterprise applications. Delivers midrange routing services for the Enterprise and SP edge networks....

Contents at a Glance

Chapter 1 Network Design Methodology 5 Chapter 2 Network Structure Models 33 Part II LAN and WAN Design 67 Chapter 3 Enterprise LAN Design 69 Chapter 4 Wireless LAN Design 111 Chapter 5 WAN Technologies 151 Chapter 6 WAN Design 181 Part III The Internet Protocol and Routing Protocols 217 Chapter 7 Internet Protocol Version 4 219 Chapter 8 Internet Protocol Version 6 257 Chapter 9 Routing Protocol Selection Criteria 289 Chapter 10 RIP and EIGRP Characteristics and Design 317 Chapter 11 OSPF and...

Converting Binary to Decimal

To convert a binary number to decimal, multiply each instance of 0 or 1 by the power of 2 associated with the position of the bit in the binary number. The first bit, starting from the right, is associated with 20 1. The value of the exponent increases by 1 as each bit is processed, working leftward. As shown in Table B-4, each bit in the binary number 10101010 has a decimal equivalent from 0 to 128 based on the value of the bit multiplied by a power of 2 associated with the bit position. This...

Converting Decimal to Hexadecimal

First things first memorize Table B-1. There are two ways to convert larger numbers. The first method is to convert decimal to binary and then convert binary to hex. The second method is to divide the decimal number by 16 the residual is the rightmost hexadecimal digit and then keep dividing until the number is not divisible anymore. For the first method, use the schemes described in later sections. For the second method, follow the examples described here. First, divide the decimal number by...

Cost

Cost is the name of the metric used by OSPF and IS-IS. In OSPF on a Cisco router, a link's default cost is derived from the interface's bandwidth. Cisco's implementation of IS-IS assigns a default cost of 10 to all interfaces. The formula to calculate cost in OSPF is 108 BW where BW is the interface's default or configured bandwidth. For 10-Mbps Ethernet, cost is calculated as follows BW 10 Mbps 10 * 106 10,000,000 107 cost (Ethernet) 108 107 10 The sum of all the costs to reach a destination...

Dense Wave Division Multiplexing

Dense Wave Division Multiplexing (DWDM) increases fiber optic's bandwidth capabilities by using different wavelengths of light called channels over the same fiber strand. It maximizes the use of the installed base of fiber used by service providers and is a critical component of optical networks. DWDM allows for service providers to increase the services offered to customers by adding new bandwidth to existing channels on the same fiber. DWDM lets a variety of devices access the network,...

Design Goals of IP Telephony

The overall goal of IP telephony is to replace traditional TDM-based telephony by deploying IPT components on existing IP networks. IPT should be highly available and as reliable as existing voice networks. IPT should provide greater flexibility and productivity while providing lower cost QoS Enabled L2 Switch QoS Enabled L3 Switch QoS Enabled L2 Switch QoS Enabled L3 Switch of ownership by using a converged network. IPT also allows third-party software providers to develop new applications for...

Determining the Network Portion of an IP Address

Given an address and mask, you can determine the classful network, the subnetwork, and the subnetwork's broadcast number. You do so with a logical AND operation between the IP address and subnet mask. You obtain the broadcast address by taking the subnet number and making the host portion all ls. Table 7-l4 shows the logical AND operation. Notice that the AND operation is similar to multiplying bit l and bit 2 if any 0 is present, the result is 0. Table 7-14 The AND Logical Operation Table 7-14...

Dialup

Dialup technology provides connectivity over the PSTN using analog modems. Although the bandwidth is relatively low, the availability of analog is very widespread. Dialup connectivity is ideal for low-bandwidth conversations of 56 kbps or less. Despite the high availability of dialup technology over analog lines, it is generally not a viable option anymore. However, a common use of dialup is when a remote worker or teleworker uses it as a backup network solution if his or her DSL or cable...

Digital Subscriber Line

Digital Subscriber Line (DSL) is a technology that provides high-speed Internet data services over ordinary copper telephone lines. It achieves this by using frequencies that are not used in normal voice telephone calls. The term xDSL describes the various competing forms of DSL available today. Some of the DSL technologies available include asymmetric (ADSL), symmetric (SDSL), high bit rate (HDSL), very high bit rate (VDSL), rate-adaptive (RADSL) and IDSL (based on ISDN). Table 5-3 summarizes...

Do I Know This Already

Integrated Transport, Integrated Service, and Integrated Application are the three phases of IIN. 2. A. Application, Interactive Services, and Network Infrastructure are the layers of SONA. 3. C. Virtualization services occur in the Interactive Service layer of SONA. 4. B. IPCC is a collaboration application. All the others are business applications. 6. A, B, C. The PPDIOO methodology has three steps. 7. D. The primary sources of network audits are existing documentation, management...

Do I Know This Already Quiz

The purpose of the Do I Know This Already quiz is to help you decide whether you need to read the entire chapter. If you already intend to read the entire chapter, you do not necessarily need to answer these questions now. The eight-question quiz, derived from the major sections in the Foundation Topics portion of the chapter, helps you determine how to spend your limited study time. Table 2-1 outlines the major topics discussed in this chapter and the Do I Know This Already quiz questions that...

Dual Stack Backbones

In this model, all routers in the backbone are dual-stack, capable of routing both IPv4 and IPv6 packets. The IPv4 protocol stack is used between IPv4 hosts, and the IPv6 protocol stack is used between IPv6 hosts. This deployment model works for organizations with a mixture of IPv4 and IPv6 applications. Figure 8-8 shows a network with a dual-stack backbone. All the WAN routers run both IPv4 and IPv6 routing protocols. The disadvantages are that the WAN routers require dual addressing, run two...

EIGRP Components

EIGRP has four components that characterize it Neighbor discovery and recovery Reliable Transport Protocol (RTP) You should know the role of the EIGRP components, which are described in the following sections. EIGRP uses different modules that independently support IP, Internetwork Packet Exchange (IPX), and AppleTalk routed protocols. These modules are the logical interface between DUAL and routing protocols such as IPX RIP, AppleTalk Routing Table Maintenance Protocol (RTMP), and IGRP. The...

EIGRP for IPv4 Summary

The characteristics of EIGRP follow Hybrid routing protocol (a distance-vector protocol that has link-state protocol characteristics). Uses IP protocol number 88. Classless protocol (supports VLSMs). Default composite metric of bandwidth and delay. You can factor load and reliability into the metric. Sends route updates to multicast address 224.0.0.10. Sends partial route updates only when there are changes. Support for MD5 authentication and fast convergence. Uses DUAL for fast convergence and...

EM Signaling

E& M is an analog signaling technique often used in PBX-to-PBX tie-lines. E& M is receive and transmit, or more commonly called ear and mouth. Cisco routers support four E& M signal types Type I, Type II, Type III, and Type V. Types I and II are most popular on the American continents. Type V is used in the United States and Europe. There are also three forms of E& M dial supervision signaling to seize the E& M trunk Immediate start This is the most basic protocol. In this...

Enterprise Campus LANs

A campus LAN connects two or more buildings within a local geographic area using a high-bandwidth LAN media backbone. Usually the enterprise owns the medium (copper or fiber). High-speed switching devices minimize latency. In today's networks, Gigabit Ethernet campus backbones are the standard for new installations. In Figure 3-10, Layer 3 switches with Gigabit Ethernet media connect campus buildings. Ensure that you implement a hierarchical composite design on the campus LAN and that you...

Enterprise Campus Module

The Enterprise Campus consists of the following submodules Figure 2-5 shows the Enterprise Campus model. The campus infrastructure consists of the campus core, building-distribution, and building-access layers. The campus core provides a high-speed switched backbone between buildings, to the server farm and to the enterprise distribution. This segment consists of redundant and fast convergence connectivity. The building-distribution layer aggregates all the closet access switches and performs...

Enterprise Data Center Infrastructure

Data centers (DC) contain different types of server technologies, including standalone servers, blade servers, mainframes, clustered servers, and virtual servers. Figure 3-14 shows the Enterprise DC. The DC access layer must provide the port density to support the servers, provide high-performance low-latency Layer 2 switching, and support dual and single connected servers. The preferred design is to contain Layer 2 to the access layer and Layer 3 on the distribution. Some solutions push Layer...

Enterprise Edge Module

As shown in Figure 2-6, the Enterprise Edge consists of the following submodules E-commerce networks and servers Internet connectivity and DMZ Figure 2-6 Enterprise Edge Module The e-commerce submodule provides highly available networks for business services. It uses the high-availability designs of the server farm module with the Internet connectivity of the Internet module. Design techniques are the same as those described for these modules. Devices located in the e-commerce submodule include...

Enterprise Teleworker Branch of One Design

At the remote edges of the network is another branch office called the Branch of One, also known as Enterprise Teleworkers. Organizations are continually trying to reduce costs and improve their employees' productivity. By working from home, employees can manage their work schedules more effectively and increase their productivity. This also results in greater job satisfaction and flexibility in the employees' work schedule. The work-from-home teleworker is an extension of the enterprise and...

Enterprise WAN Architecture

When selecting an enterprise WAN architecture, you should identify and understand the connectivity and business requirements. It is important to review sample network designs that could meet the identified requirements. Here are some common factors that influence decisions High availability Most businesses need a high level of availability, especially for their critical applications. The goal of high availability is to remove the single points of failure in the design, either by software,...

F

Falcon Communications scenario, 579, 581 Fast EtherChannel, network design guidelines, 79 Fast Ethernet, network design rules, 74 100BASE-FX, 75 100BASE-T, 75 100BASE-T4, 75 100BASE-TX, 75 FHSS (frequency-hopping spread spectrum), 114 fields of IPv6 header, 261-262 firewalls as Cisco Self-Defending Network technology, 470 flat routing protocols, 297 floating static routes, 58 flooding, 82 flow control, 622 flush timer (RIP), 323 forwarding information base (RIPvl), 321 forwarding information...

Features of This Book

Do I Know This Already Quizzes Each chapter begins with a quiz that helps you determine how much time you need to spend studying that chapter. If you follow the directions at the beginning of the chapter, the Do I Know This Already quiz directs you to study all or particular parts of the chapter. Foundation Topics These are the core sections of each chapter. They explain the protocols, concepts, and configuration of the topics in that chapter. If you need to learn about the topics in a...

Foundation Summary

The Foundation Summary section of each chapter lists the most important facts from the chapter. Although this section does not list every fact from the chapter that will be on your CCDA exam, a well-prepared CCDA candidate should at a minimum know all the details in each Foundation Summary before taking the exam. This chapter has covered the following topics you need to master for the CCDA exam RIPv2 The enhancements in Version 2 of RIP to support network designs RIPng New RIP for IPv6 networks...

Foundation Topics

With the complexities of network design, the CCDA needs to understand network models used to simplify the design process. The hierarchical network model was one of the first Cisco models that divided the network into core, distribution, and access layers. The Cisco Enterprise Architecture is a model that provides a functional modular approach to network design. In addition to a hierarchy, modules are used to organize server farms, network management, campus networks, WANs, and the Internet.

Ground Start Signaling

Ground-start signaling is an analog signaling technique used to indicate on-hook and off-hook conditions. Ground-start is commonly used in switch-to-switch connections. The difference between ground-start and loop-start is that ground-start requires the closing of the loop at both locations. Ground-start is commonly used by PBXs. The standard way to transport voice between two telephone sets is to use tip and ring lines. Tip and ring lines are the twisted pair of wires that connect to your...

H

H.323, 523-524 hardware compression, 170 header fields of IPv4, 222-224 DS, 226 ToS, 225-226 of IPv6, 261-262 Hello packets EIGRP, 339 OSPF, 359 hexadecimal numeric system, 626 converting to decimal, 629-630 hierarchical LAN architecture, 36 access layer, 39-40, 86-87 core layer, 38, 88 distribution layer, 38-39, 87-88 examples of, 40 hierarchical routing protocols, 297 high-availability network designs media redundancy, 57-58 route redundancy, 55-56 server redundancy, 55 workstation-to-router...

Hierarchical Model Examples

You can implement the hierarchical model by using either routers or switches. Figure 2-2 is an example of a switched hierarchical design in the enterprise campus. In this design, the core provides high-speed transport between the distribution layers. The building-distribution layer provides redundancy and allows policies to be applied to the building-access layer. Layer 3 links between the core and distribution switches are recommended to allow the routing protocol to take care of load...

Hierarchical Network Design

As shown in Figure 2-1, a traditional hierarchical LAN design has three layers The core layer provides fast transport between distribution switches within the enterprise campus. The distribution layer provides policy-based connectivity. The access layer provides workgroup and user access to the network. Figure 2-1 Hierarchical Network Design Has Three Layers Core, Distribution, and Access Each layer provides necessary functionality to the enterprise campus network. You do not need to implement...

Hierarchical Network Models

Hierarchical models enable you to design internetworks that use specialization of function combined with a hierarchical organization. Such a design simplifies the tasks required to build a network that meets current requirements and can grow to meet future requirements. Hierarchical models use layers to simplify the tasks for internetworking. Each layer can focus on specific functions, allowing you to choose the right systems and features for each layer. Hierarchical models apply to both LAN...

Hop Count

The hop count parameter counts the number of links between routers the packet must traverse to reach a destination. The RIP routing protocol uses hop count as the metric for route selection. If all links were the same bandwidth, this metric would work well. The problem with routing protocols that use only this metric is that the shortest hop count is not always the most appropriate path. For example, between two paths to a destination network one with two 56-kbps links and another with four T1...

How This Book Is Organized

This book is divided into the following parts Part I General Network Design (Chapters 1 and 2) Part II LAN and WAN Design (Chapters 3 through 6) Part III The Internet Protocol and Routing Protocols (Chapters 7 through 12) Part IV Security, Convergence, and Network Management (Chapters 13 through 16) Part V Comprehensive Scenarios (Chapter 17) Part VI Appendixes (Appendixes A and B) The CCDA Exam Topics section describes the design topics that are covered on the CCDA exam. Before you begin...

Huband Spoke Topology

A star or hub-and-spoke topology provides a hub router with connections to the spoke routers through the WAN cloud. Network communication between the sites flows through the hub router. Significant WAN cost savings and simplified management are benefits of the hub-and-spoke topology. Hub and spoke topologies also tend to be the most popular WAN topologies. A major disadvantage of this approach is that the hub router represents a single point of failure. The hub-and-spoke topology limits overall...

Identifying Customer Requirements

To obtain customer requirements, you need to not only talk to network engineers, but also talk to business unit personnel and company managers. Networks are designed to support applications you want to determine the network services that you need to support. The steps to identify customer requirements are as follows Step 1 Identify network applications and services. Step 2 Define the organizational goals. Step 3 Define the possible organizational constraints. Step 4 Define the technical goals....

Identity and Access Control Deployments

Validating user authentication should be implemented as close to the source as possible, with an emphasis on strong authentication for access from untrusted networks. Access rules should enforce policy deployed throughout the network with the following guidelines Source-specific rules with any type destinations should be applied as close to the source as possible. Destination-specific rules with any type sources should be applied as close to the destination as possible. Mixed rules integrating...

Implement Phase

New equipment is installed and configured in the Implement phase. New devices replace or augment the existing infrastructure. The project plan is followed during this phase. Planned network changes should be communicated in change control meetings, with necessary approvals to proceed. Each step in the implementation should includes a description, detailed implementation guidelines, estimated time to implement, rollback steps in case of a failure, and any additional reference information. As...

Integrity Violations and Confidentiality Breaches

When attackers change sensitive data without the proper authorization, this is called an integrity violation. For example, an attacker might access financial data and delete critical information. The effect of this change may not be felt for some time or until a significant loss has occurred. Integrity attacks like this are considered by many companies to be one of the most serious threats to their business. Furthermore, identifying these attacks can be very difficult, and the effects can be...

Pv4 Address Subnets

Subnetting plays an important part in IPv4 addressing. The subnet mask helps determine the network, subnetwork, and host part of an IP address. The network architect uses subnetting to manipulate the default mask to create subnetworks for LAN and WAN segments. These subnetworks provide enough addresses for LANs of different sizes. Point-to-point WAN links usually get a subnet mask that allows for only two hosts because only two routers are present in the point-to-point WAN link. You should...

Pv4 Header

The best way to understand IPv4 is to know the IPv4 header and all its fields. Segments from TCP or the User Datagram Protocol (UDP) are passed on to IP for processing. The IP header is appended to the TCP or UDP segment. The TCP or UDP segment then becomes the IP data. The IPv4 header is 20 bytes in length when it uses no optional fields. The IP header includes the addresses of the sending host and destination host. It also includes the upper-layer protocol, a field for prioritization, and a...

Pv6 Multicast Address

The IPv6 multicast (one-to-many) address identifies a set of hosts. The packet is delivered to all the hosts identified by that address. This type is similar to IPv4 multicast (Class D) addresses. IPv6 multicast addresses also supersede the broadcast function of IPv4 broadcasts. You use an all-nodes multicast address instead. FF01 0 0 0 0 0 0 1 Indicates all-nodes address for interface-local scope. FF02 0 0 0 0 0 0 2 All-routers address for link-local.

Pv6 Multicast Addresses

IPv6 retains the use and function of multicast addresses as a major address class. IPv6 prefix FF00 8 is allocated for all IPv6 multicast addresses. IPv6 multicast addresses are described in RFC 2373. EIGRP for IPv6, OSPFv3, and RIPng routing protocols use multicast addresses to communicate between router neighbors. The format of the IPv6 multicast address is described in Chapter 8, Internet Protocol Version 6. The common multicast addresses are repeated in Table 12-3. Table 12-3 Well-Known...

Pv6 over IPv4 Tunnels

In this deployment model, pockets of IPv6-only networks are connected using IPv4 tunnels. With tunneling, IPv6 traffic is encapsulated within IPv4 packets so that they are sent over the IPv4 WAN. The advantage of this method is that you do not need separate circuits to connect the IPv6 networks. A disadvantage of this method is the increased protocol overhead of the encapsulated IPv6 headers. Tunnels are created manually, semiautomatedly, or automatically using 6to4. RFC 3056 specifies the 6to4...

Isdn

Integrated Services Digital Network (ISDN) is an all-digital phone line connection that was standardized in the early 1980s. ISDN allows both voice and data to be transmitted over the digital phone line instead of the analog signals used in dialup connections. ISDN provides greater bandwidth and lower latency compared to dialup analog technology. ISDN comes in two service types Basic Rate Interface (BRI) and Primary Rate Interface (PRI). ISDN is comprised of digital devices and reference...

ISIS Operation and Design

This subsection discusses IS-IS areas, designated routers, authentication, and the NET. IS-IS defines areas differently from OSPF area boundaries are links and not routers. IS-IS has no BDRs. Because IS-IS is an OSI protocol, it uses a NET to identify each router. To configure the IS-IS routing protocol, you must configure a NET on every router. Although configuring NET is not a CCDA test requirement, this information is included for extra credit. Although you can configure IS-IS to route IP,...

Large Building LANs

Large-building LANs are segmented by floors or departments. The building-access component serves one or more departments or floors. The building-distribution component serves one or more building-access components. Campus and building backbone devices connect the data center, building-distribution components, and the Enterprise Edge-distribution component. The access layer typically uses Layer 2 switches to contain costs, with more expensive Layer 3 switches in the distribution layer to provide...

Loop Start Signaling

Loop-start signaling is an analog signaling technique used to indicate on-hook and off-hook conditions in the network. It is commonly used between the telephone set and the CO, PBX, or FXS module. As shown in Figure 15-3, with loop-start the local loop is open when the phone is on-hook. When the phone is taken off-hook, a -48 direct current (DC) voltage loops from the CO through the phone and back. Loop-start signaling is used for residential lines.

Low Latency Queuing

Low-Latency Queuing (LLQ) adds a strict priority queue to CBWFQ. The strict priority queue allows delay-sensitive traffic such as voice to be sent first, before other queues are serviced. That gives voice preferential treatment over the other traffic types. Without LLQ, CBWFQ would not have a priority queue for real-time traffic. The additional classification of other traffic classes is done using the same CBWFQ techniques. LLQ is the standard QoS method of choice for Voice over IP networks.

Lwapp

Lightweight Access Point Protocol (LWAPP) is a draft Internet Engineering Task Force (IETF) standard for control messaging for setup, authentication, and operations between access points (AP) and wireless LAN controllers (WLC). With Cisco's UWN Split-MAC operation, the control and data messages are split. Lightweight Access Points (LWAP) communicate with the WLCs using control messages over the wired network. LWAPP data messages are encapsulated and forwarded to and from wireless clients. The...

Media Redundancy

In mission-critical applications, it is often necessary to provide redundant media. In switched networks, switches can have redundant links to each other. This redundancy is good because it minimizes downtime, but it can result in broadcasts continuously circling the network, which is called a broadcast storm. Because Cisco switches implement the IEEE 802.1d spanning-tree algorithm, you can avoid this looping in Spanning Tree Protocol (STP). The spanning-tree algorithm guarantees that only one...

Multicast Traffic Considerations

Internet Group Management Protocol (IGMP) is the protocol between end workstations and the local Layer 3 switch. IGMP is the protocol used in multicast implementations between the end hosts and the local router. RFC 2236 describes IGMP version 2 (IGMPv2). RFC 1112 describes the first version of IGMP. IP hosts use IGMP to report their multicast group memberships to routers. IGMP messages use IP protocol number 2. IGMP messages are limited to the local interface and are not routed. RFC 3376...

Multiprotocol Label Switching

MPLS is technology for the delivery of IP services using labels (numbers) to forward packets. In normal routed environments, packets are forwarded by the router performing a Layer 3 destination address lookup and rewriting the Layer 2 addresses. MPLS functions by encapsulating packets with headers that include the label information. As soon as packets are marked with a label, specific paths through the network can be designed to correspond to that distinct label. MPLS labels can be based on...

Multisite Centralized WAN Call Processing Model

The centralized WAN call-processing model is a solution for medium enterprises with one large location and many remote sites. Figure 15-12 shows the centralized call-processing model. A CM cluster with multiple servers is deployed for redundancy at the large site. Call processing and voice mail servers are located in only the main site. Remote-site IP phones register to the CM cluster located in the main site. PoE switches are used to power all IP phones. Remote sites use voice-enabled gateway...

Multisite Distributed WAN Call Processing Model

The multisite distributed WAN call-processing model is a solution for large enterprises with several large locations. Figure 15-13 shows the distributed WAN model. Up to 30,000 users are supported per CM cluster. Several CM clusters are deployed at the large sites for redundancy, and Unity servers are used for messaging. Intercluster trucks are created to establish communication between clusters. IP phones are deployed on PoE LAN switches. This model also supports remote sites to be distributed...

Multi Tier Design

The multi-tier design is the largest of the branch profiles, supporting between 100 and 1000 users. This design profile is similar to the dual-tier design in that it also provides dual-access routers in the WAN edge. In addition, dual ASAs are used for firewall filtering, and dual distribution switches provide the multilayer switching component. The WAN services use an MPLS deployment model with dual WAN links into the WAN cloud. Because there are dual routers, the typical redundancy services...

Network Audit Tools

When performing a network audit, you have three primary sources of information Existing network management software New network management tools After gathering the existing documentation, you must obtain access to the existing management software. The client may already have CiscoWorks tools from which you can obtain hardware models and components and software versions. You can also obtain the existing router and switch configurations. The network audit should provide the following information...

OSPFv2

RFC 2328 defines OSPFv2, a link-state routing protocol that uses Dijkstra's shortest path first (SPF) algorithm to calculate paths to destinations. OSPFv2 is used in IPv4 networks. OSPF was created for its use in large networks where RIP failed. OSPF improved the speed of convergence, provided for the use of VLSMs, and improved the path calculation. In OSPF, each router sends link-state advertisements about itself and its links to all other routers in the area. Note that it does not send...

OSPFv2 Summary

OSPFv2 is used in large enterprise IPv4 networks. The network topology must be hierarchical. OSPF is used in the enterprise campus building access, distribution, and core layers. OSPF is also used in the enterprise data center, WAN MAN, and branch offices. The characteristics of OSPFv2 follow Link-state routing protocol. Classless protocol (supports VLSMs and CIDR). Metric is cost (based on interface bandwidth by default). Fast convergence. Uses link-state updates and SPF calculation. Reduced...

OSPFv3 Areas and Router Types

OSPFv3 retains the same structure and concepts as OSPFv2. The area topology, interfaces, neighbors, link-state database, and routing table remain the same. RFC 2740 does not define new The OSPF areas shown in Figure 11-2 and the router types shown in Figure 11-3 remain the same. The router types in relation to the OSPF areas are Internal router Any router whose interfaces all belong to the same OSPF area. These routers keep only one link-state database. ABR Routers that are connected to more...

OSPFv3 Link State Advertisements

OSPFv3 retains the LSA types used by OSPFv2 with some modifications and introduces two new LSAs Link LSA and Intra-Area-Prefix. All LSAs use a common 20-byte header that indicates the LS type, the advertising router, and the sequence number. Figure 11-7 shows the format of the LSA header. The LS age indicates the time in seconds since the LSA was generated. The LS type indicates the function performed by this LSA. This field includes a U bit and S2 and S1 bits. When the U bit is set to 0, the...

OSPFv3 Summary

The characteristics of OSPFv3 follow Link-state routing protocol for IPv6. Metric is cost (based on interface bandwidth by default). Sends partial route updates only when changes occur. Routes are labeled as intra-area, interarea, external Type 1, or external Type 2. Uses IPv6 for authentication. Uses the Dijkstra algorithm to calculate the SPF tree. Default administrative distance is 110. Uses multicast address FF02 5 (ALLSPFRouters). Uses multicast address FF02 6 (ALLDRouters). Recommended...

P

See LSAs packet-switched WANs, 185 partial-mesh topologies, 187 passwords, 445 PAT (port address translation), 232 path MTU discovery, 272 PBR (policy-based routing), 402 PBXs, 500 Q.SIG, 506 PCM (Pulse Code Modulation), 520 PDIOO lifecycle, 13, 167-168 Design phase, 14 top-down design process, 21-22 Implement phase, 14 Operate phase, 14 Optimize phase, 15 Plan phase, 14 Prepare phase, 14 PE (provider edge) routers, 161 Pearland Hospital scenario, 569-571, 573 peer-to-peer VPNs,...

PBX and PSTN Switches

Traditional switches and PBXs route voice using TDM technology and use 64-kbps circuits. The CCDA must understand some of the differences between these devices. The PBX, as its name states, is used in a private network and uses proprietary protocols. The PBX is located in the enterprise's data center. Each PBX may scale up to 1000 phones. Companies deploy PBX networks to obtain enterprise features and to prevent PSTN long-distance charges. PBXs are customer-owned voice switches. Enterprise...

Prepare Plan Design Implement Operate and Optimize Phases

Cisco has formalized a network's life cycle into six phases Prepare, Plan, Design, Implement, Operate, and Optimize. These phases are collectively known as PPDIOO. The PPDIOO life cycle It lowers the total cost of ownership by validating technology requirements and planning for infrastructure changes and resource requirements. It increases network availability by producing a sound network design and validating the network operation. It improves business agility by establishing business...

PSTN Numbering Plan

The PSTN uses the ITU E.164 standard for public network addressing. The E.164 standard uses a maximum of 15 digits and makes each phone unique in the PSTN. Examples of E.164 addresses are the residential, business, IP phones, and cell phones that you use every day. Each country is assigned a country code to identify it. The country codes can be one to three digits in length. Table 15-4 shows some examples of country codes. The ITU website that lists country codes is located at e164_763.html....

Qa

As mentioned in the Introduction, you have two choices for review questions here in the book or the exam questions on the CD-ROM. The answers to these questions appear in Appendix A. For more practice with exam format questions, use the exam engine on the CD-ROM. 1. What two routing protocols do not carry mask information in the route updates 2. True or false Link-state routing protocols send periodic routing updates. 3. True or false RIPv2 was created to support IPv6. 4. True or false The path...

References and Recommended Readings

CCIE Routing and Switching Exam Certification Guide. Indianapolis Cisco Press, 2002. Doyle, J. Routing TCP IP, Volume I. Indianapolis Cisco Press, 1998. Enhanced IGRP. Enhanced Interior Gateway Routing Protocol. Hedrick, C. RFC 1058, Routing Information Protocol. Available from http www.ietf.org rfc. Implementing EIGRP for IPv6. Malkin, G. RFC 1723, RIP Version 2 - Carrying Additional Information. Available from http www.ietf.org rfc. Malkin, G. RFC 2453, RIP Version 2. Available from...

Remote Modules

The remote modules of the Cisco Enterprise Architecture model are the Enterprise Branch, Enterprise Data Center, and Enterprise Teleworker modules. The Enterprise Branch normally consists of remote offices or sales offices. These branch offices rely on the WAN to use the services and applications provided in the main campus. Infrastructure at the remote site usually consists of a WAN router and a small LAN switch, as shown in Figure 2-12. Instead of MPLS or Frame Relay, it is common to use...

RIPv1 Message Format

The RIPvl message format is described in RFC 1058 and is shown in Figure 10-1. The RIP messages are encapsulated using User Datagram Protocol (UDP). RIP uses the well-known UDP port 520. 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 IP address (2nd route entry - up to 25) Command Describes the packet's purpose. The RFC describes five commands, two of which are obsolete and one of which is reserved. The two used commands are Request Requests all or part of the responding...

RIPv1 Timers

The Cisco implementation of RIPv1 uses four timers RIPv1 sends its full routing table out all configured interfaces. The table is sent periodically as a broadcast (255.255.255.255) to all hosts. The update timer specifies the frequency of the periodic broadcasts. By default, the update timer is set to 30 seconds. Each route has a timeout value associated with it. The timeout gets reset every time the router receives a routing update containing the route. When the timeout value expires, the...

RIPv2 Message Format

The RIPv2 message format takes advantage of the unused fields in the RIPvl message format by adding subnet masks and other information. Figure 10-3 shows the RIPv2 message format. 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 IP address (2nd route entry - up to 25) Command Indicates whether the packet is a request or response message. The request message asks that a router send all or a part of its routing table. Response messages contain route entries. The router sends the...

Roaming and Mobility Groups

The primary reason to have wireless networks is the ability to access network resources from common areas and in areas difficult to run cables. End clients might want to move from one location to another. Mobility allows users to access the network from several locations. Roaming occurs when the wireless client changes association from one access point to another. The challenge is to scale the wireless network to allow client roaming. Roaming can be intracontroller or intercontroller....

Scenario Four Answers

The current Falcon network is not scalable. It is a flat network architecture using Layer 2 links in the core with no hierarchy. It does not have core, distribution, and access layers. 2. Recommend inserting a distribution layer to create a hierarchy between the core and access layers. Use Layer 3 links instead of Layer 2 links to prevent spanning-tree loop broadcast storms. 3. All hubs need to be replaced with switches. All switches should be replaced with PoE switches to provide power to...

Scenario Four Falcon Communications

Falcon Communications has requested an assessment of its current network infrastructure. You are given the diagram shown in Figure 17-5. The current infrastructure contains three 6500 Catalyst switches connected using Layer 2 links. Building access switches, WAN routers, Internet firewalls, the mainframe, and Windows servers all connect to the 6500 switches. Some Fast Ethernet hubs are used on the network. The IT manager mentions that they experience sporadic network outages several times...

Scenario One Answers

The hospital needs to provide access to patient records, prescriptions, and information from patient rooms. 2. No cost restrictions were discussed. 3. The technical requirements are as follows WLAN access from rooms on floors 6 through 10 Redundant access to servers in the data center Fast switching between LAN segments 4. The technical constraint is as follows Servers must be located in the first floor data-center rooms. 5. Figure 17-1 shows the logical diagram of the current network. Figure...

Scenario One Pearland Hospital

Robertson, the IT director at Pearland Hospital, is responsible for managing the network. Mr. Robertson has requested your help in proposing a network solution that will meet the hospital's requirements. The hospital is growing, and the management has released funds for network improvements. The medical staff would like to be able to access medical systems using laptops from any of the patient rooms. Doctors and nurses should be able to access patient medical records, x-rays, prescriptions,...

Server Farm Module

The server-farm or data-center module provides high-speed access to servers for the campus networks. You can attach servers to switches via Gigabit Ethernet or 10 Gigabit Ethernet. Some campus deployments might need EtherChannel technology to meet traffic requirements. Figure 3-13 shows an example of a server-farm module for a small network. Servers are connected via Fast Ethernet or Fast EtherChannel. The server-farm switches connect via redundant uplink ports to the core switches. The largest...

Small and Remote Site LANs

Small and remote sites usually connect to the corporate network via a small router. The LAN service is provided by a small LAN switch. The router filters broadcast to the WAN circuit and forward packets that require services from the corporate network. You can place a server at the small or remote site to provide DHCP and other local applications such as a backup domain controller and DNS if not, you must configure the router to forward DHCP broadcasts and other types of services. As the site...

Sona

SONA is an architectural framework that guides the evolution of enterprise networks to IIN to support new IT strategies. With SONA, distributed applications and services are centrally managed over a common, unified platform. An integrated system allows access to networked applications and services from all locations with greater speed and service quality. Figure 1-1 shows the SONA framework and the offerings included at each layer. SONA networks are based on a three-layer design that...

Strategies for Exam Preparation

The strategy you use for the CCDA test might be slightly different from strategies used by other readers, mainly based on the skills, knowledge, and experience you already have obtained. For instance, if you have attended the DESGN course, you might take a different approach than someone who learned switching via on-the-job training. Regardless of the strategy you use or your background, this book is designed to help you get to the point where you can pass the exam with the least amount of time...

Token Ring Design Rules

Token Ring is not a CCDA test subject but this section is included for reference because you might find Token Ring on existing networks. IBM developed Token Ring in the 1970s. In the 1980s, Token Ring and Ethernet competed as the preferred medium for LANs. The IEEE developed the IEEE 802.5 specification based on the IBM Token Ring specifications. The 802.5 working group is now inactive. The most recent specification is IEEE 802.5-1998. You can find more information at http www.8025.org. Table...

Top Down Approach

Top-down design simply means starting your design from the top layer of the OSI model and working your way down. Top-down design adapts the network and physical infrastructure to the network application's needs. With a top-down approach, network devices and technologies are not selected until the applications' requirements are analyzed. Figure 1-3 shows a top-down structure design process. The design process begins with the applications and moves down to the network. Notice that SONA's Network...

Traffic Shaping and Policing

Traffic shaping and policing are mechanisms that take an action based on the traffic's characteristics, such as DSCP or IP precedence bits set in the IP header. Traffic shaping slows down the rate at which packets are sent out an interface by matching certain criteria. Traffic shaping uses a token bucket technique to release the packets into the output queue at a preconfigured rate. Traffic shaping helps eliminate potential bottlenecks by throttling back the traffic rate at the source. Policing...

Trust and Identity Management

Trust and Identity Management is part of the Cisco Self-Defending Network, which is crucial for the development of a secure network system. It defines who and what can access the network, as well as when, where, and how that access can occur. Access to the business applications and network equipment is based on the user level rights granted to users. Trust and Identity Management also attempts to isolate and keep infected machines off the network by enforcing access control. The three main...

Using EoIP Tunnels for Guest Services

Basic solutions use separate VLANs for guest and corporate users to segregate guest traffic from corporate traffic. The guest SSID is broadcast, but the corporate SSID is not. All other security parameters are configured. Another solution is to use Ethernet over IP (EoIP) to tunnel the guest traffic from the LWAPP to an anchor WLC. As shown in Figure 4-12, EoIP is used to logically segment and transport guest traffic from the edge AP to the anchor WLC. There is no need to define guest VLANs in...