Scenario 1 You Have CCNA Certification

Because you have taken other Cisco exams, you know what you are up against in the test experience. The Remote Access exam is like the others. The questions are Sylvanish, and the answers are sometimes confusing if you read too much into them. The best approach with this book, because you have not taken the course, is to take each chapter's Do I Know This Already quiz to determine what to look for as you read the chapter. Once you have completed a chapter, take the end-of-chapter test to see how...

Cisco Remote Connection Products

This chapter covers the selection of products for the central office, the branch office, and the SOHO or RO. The key is to know where product families fit, not to memorize individual product part numbers or codes. For instance, you can get by knowing the capabilities of the 3600 product family as compared to the 1600 product family, without getting into the granular details of either. The bulk of the information in this chapter leads the engineer to ask the right questions when embarking on a...

A

The only protocol or configuration attributes configured on the physical interface are the individual commands that make the BRI interface a part of the rotary group and the encapsulation. On dialer pool interfaces, you can set a priority to specify the order in which the interfaces are used. With rotary groups, that granularity is not possible. All protocol attributes are entered at the logical dialer interface configuration level. The use of dialer profiles versus rotary groups comes down to...

AAA Accounting

AAA accounting can supply information concerning user activity back to the database. This concept was especially helpful in the early days of Internet service when many ISPs offered 20 or 40 hours per week at a fixed cost and hourly or minute charges in excess of the specified timeframe. Today it is much more common for the ISP charge to be set for an unlimited access time. This does not, however, minimize the power of accounting to enable the administrator to track unauthorized attempts and...

AAA Authorization

Once a user has been authenticated, he or she can be further restricted in what he or she is allowed to do. This is done using the aaa authorization command. These restrictions can be applied to activities or services offered on the router. As with the authentication, it is easier to see an example before diving into each option available. The syntax is quite simple and declares which activity or service (network, exec, command level, config-commands, and reverse-access) is being attempted and...

AAA Configuration

AAA configuration is implemented in three steps Step 1 Enable AAA Configuration on the router. During the declaration of AAA, the router must be told if it will be speaking with a Terminal Access Control Access Control System (TACACS) or RADIUS server. Step 2 Define who will be authenticated, what they are authorized to do, and what will be tracked in the database. Step 3 Enable or define the method on the interface. The following sections detail how to turn on AAA (Step 1), how to define the...

Additional Configuration Options

In some cases, you must tweak the default settings of an X.25 installation based on service provider mandates or customer requests. There are a number of items that can be configured to change the way in which X.25 operates Range of VCs Incoming, outgoing, and two-way circuits are possible options. Packet size Inbound and outbound packet size can be specified on the interface. Window size Inbound and outbound window size can be specified on the interface. Window modulus This is the limit of the...

Advanced DDR Operations

Up to this point, the discussion has been based in the basics of DDR. With a more solid understanding of the technological base of ISDN and DDR implementations, it is now appropriate to discuss some additional, and more advanced, features available with DDR. DDR installations are capable of utilizing dialer profiles (utilizing virtual dialer interfaces) and rotary groups. The installations also provide redundancy through dial backup and enable the use of dynamic routes across a DDR link while...

Answers to Chapter 2 Do I Know This Already Quiz

1 What are the selection criteria for selecting a router platform Availability, bandwidth, cost, ease of management, applications and traffic patterns, backup needs and QOS, and access control requirements are the selection criteria.0. 2 Which of the following does not affect the installation of a router The answer is d, router port density. The router, and thus its port density, is selected after the requirements are established. 3 In routing, what is meant by the term availability...

Answers to Chapter 2 QA Section

1 What are the selection criteria for selecting a router platform Availability, bandwidth, cost, ease of management, applications and traffic patterns, backup needs and QOS, and access control requirements are the selection criteria. 2 Which of the following does not affect the installation of a router The answer is d, router port density. The router, and thus its port density, is selected after the requirements are established. 3 Of the 3600, 4800, 5300, and 7100 series routers, which provides...

Answers to Chapter 3 Do I Know This Already Quiz

1 Which router is best used as a central site router 2611, 3640, or 1004 The 3640 router provides more power than the 2611 or 1004. Therefore, it is the best choice of the three for a central site router. 2 Which router best serves as a small office or home office (SOHO) router for telecommuters 7200, 700, or 7500 The 700 router is best suited for the role of a SOHO router. The 7200 and 7500 routers are suited for roles as core routers. 3 Which WAN technology is best suited for providing...

Answers to Chapter 4 Do I Know This Already Quiz

1 What pins are used for modem control Pins 6, 8, and 20 are used for modem control. 2 What is the standard for DCE DTE signaling The standard is EIA TIA 232. 3 In character mode using reverse Telnet, what is the command to connect to the first async port on a 2509 router that has a loopback interface of 192.168.1.1 4 What port range is reserved for accessing an individual port using binary mode The port range is 6000-6999. 5 If a four-port serial (A S) module is in the second slot on a 3640...

Answers to Chapter 4 QA Section

1 What pins are used for modem control Pins 6, 8, and 20 are used for modem control. 2 What is the standard for DCE DTE signaling The standard is EIA TIA 232. 3 If the user wants to terminate a call, what pin does the DTE device drop to signal the modem 4 What must be done to terminate a reverse Telnet session with an attached modem You must press Ctrl+Shift+6, press x, and then execute a disconnect. 5 In character mode using reverse Telnet, what is the command to connect to the first async...

Answers to Chapter 5 Do I Know This Already Quiz

1 Where is PPP typically implemented PPP is typically implemented on ISDN lines however, it is also used in point-to-point dedicated circuits. 2 What is the function of the LCP The PPP LCP provides a method of establishing, configuring, maintaining, and terminating a point-to-point connection. 3 What is the difference between interactive and dedicated asynchronous implementations Interactive asynchronous (async) implementations enable the dial-up user to see and access the router prompt....

Answers to Chapter 5 QA Section

1 Where is PPP typically implemented It is typically implemented on ISDN lines however, it is also used in point-to-point dedicated circuits. 2 What is the function of the LCP The PPP LCP provides a method of establishing, configuring, maintaining, and terminating a point-to-point connection. 3 What is the difference between interactive and dedicated asynchronous implementations Interactive async implementations enable the dial-up user to see and access the router prompt. Dedicated async...

Answers to Chapter 6 Do I Know This Already Quiz

1 List the two most common implementations of ISDN. The two most common implementations of ISDN are BRI and PRI. 2 List the number of bearer channels for BRI, T1 PRI, and E1 PRI. The numbers are BRI 2, T1 PRI 23, and E1 PRI 30. 3 What type of information is carried over the D channel Signaling (and sometimes data, depending on the implementation) is carried over the D channel. 4 List the specifications that define Layer 2 and Layer 3 of ISDN. The specifications are Layer 2 Q.921 and Layer 3...

Answers to Chapter 6 QA Section

1 List the two most common implementations of ISDN. The two most common implementations are BRI and PRI. 2 List the number of bearer channels for BRI, T1 PRI and El PRI. The numbers are BRI 2, T1 PRI 23, and E1 PRI 30. 3 What type of information is carried over the D channel Signaling (and sometimes data, depending on the implementation) is carried over the D channel. 4 List the specifications that define Layer 2 and Layer 3 of ISDN. The specifications are Layer 2 Q.921 and Layer 3 Q.931. 5...

Answers to Chapter 7 Do I Know This Already Quiz

They stand for small office home office and remote office. The difference between them is slight the 700 is positioned for a SOHO and not generally positioned for a RO. This should be remembered when selecting equipment during the test. 2 What are the three permanent profiles for the 700 series router The profiles are LAN, standard, and internal. 3 For what is the internal profile used The internal profile is used when routing is enabled and provides the...

Answers to Chapter 7 QA Section

1 What are the three permanent profiles for the 700 series router The profiles are LAN, standard, and internal. 2 Which one of the following statements is true a. Any protocol routed in the LAN must be routed in the user profile. b. Any protocol routed in the LAN cannot be routed in the user profile. c. Any protocol routed in the LAN must be bridged in the user profile. d. Any protocol routed in the LAN cannot be bridged in the internal profile. The answer is a. Any protocol routed in the LAN...

Answers to the Chapter 10 Do I Know This Already Quiz

1 Where on a router is queuing implemented Queuing should be implemented on low-speed WAN interfaces only. 2 When should queuing be considered a viable implementation Queuing should be considered a solution when the router experiences more than occasional congestion. If the existing traffic flow is having problems getting through the router on a regular basis, queuing should be considered. 3 Should a queuing strategy be implemented on all WAN interfaces No. Queuing should be implemented on...

Answers to the Chapter 11 Do I Know This Already Quiz

1 What are the benefits of NAT The benefits of NAT include conservation, overlap dysfunction, flexibility, and the elimination of renumbering. Addresses are conserved because real addresses are not needed for the private network. Overlap dysfunction occurs when two companies, which were using the same address space, merge. Renumbering occurs when a company changes ISPs and keeps the same internal address space. When this occurs, only the NAT device requires a change. 2 What are the...

Answers to the Chapter 12 Do I Know This Already Quiz

It stands for authentication, authorization, and accounting. Authentication provides a method of identifying users. During the authentication process, the user login (name) and password are checked against the AAA database. 3 What is the difference between character mode and packet mode Character mode sends keystrokes to the router through the TTY, vty, AUX, and CON ports for configuration or query commands. Packet mode uses interface mode or a link protocol session to communicate with a device...

Answers to the Chapter 8 Do I Know This Already Quiz

The Layer 2 is LAPB. 2 Name the Layer 3 of X.25. The Layer 3 is X.25. 3 In X.25, what are the two possible roles that a router can play The roles are DCE and DTE. 4 What is the function of a Packet Assembler Disassembler (PAD) in an X.25 network The PAD is a device that collects data from asynchronous terminals and outputs that data encapsulated inside X.25 packets. 5 The addressing scheme in X.25 is known as what kind of address It is known as X.121 addressing. 6...

Answers to the Chapter 8 QA Section

The Layer 2 is LAPB. 2 Name the Layer 3 of X.25. The Layer 3 is X.25. 3 In X.25, what are the two possible roles that a router can play The roles are DCE and DTE. 4 What is the function of a PAD in an X.25 network The PAD is a device that collects data from asynchronous terminals and outputs that data encapsulated inside of X.25 packets. 5 The addressing scheme in X.25 is known as what kind of address It is known as X.121 addressing. 6 List the parts of the...

Answers to the Chapter 9 Do I Know This Already Quiz

1 Is Frame Relay connection-oriented or connectionless Frame Relay is connection-oriented. Answers to the Chapter 9 Do I Know This Already Quiz 425 2 Frame Relay virtual circuits come in two flavors. What are those flavors Frame Relay virtual circuits can be PVC or SVC. 3 Frame Relay virtual circuits are logically defined by a DLCI. What is the range of valid DLCIs Valid DLCIs fall in the range of 16-1007. 4 The Frame Relay star topology is also known as what It is also known as hub and spoke....

Answers to the Chapter 9 QA Section

1 Is Frame Relay connection-oriented or connectionless Frame Relay is connection-oriented. 2 Frame Relay virtual circuits come in two flavors. What are those flavors Frame Relay virtual circuits can be PVC or SVC. 3 Frame Relay virtual circuits are logically defined by a DLCI. What is the range of valid DLCIs Valid DLCIs fall in the range of 16-1007. 4 The Frame Relay star topology is also known as what It is also known as hub and spoke 5 In a 40-route Frame Relay network running in a full mesh...

AS5X00 Router Series

This family of routers is an Access Server line (hence the AS in the name). The available models in the line are the AS5200, the AS5300, and the AS5800. The series also includes a very highend model known as the AccessPath. It consists of a number of AS5300s operating together in a single integrated rack with a Catalyst switch collocated. The AS5X00 family of devices can provide carrier class service scalability as well as multiprotocol routing services. These devices are usually deployed in an...

Available Connections

For this section, refer to Figure 3-3, which represents a number of technologies. Note that if all the labels are removed from the figure, the various connectivity possibilities become numerous. Serial V.35, X.21, RS232 EIA TIA-449, EIA-530 Serial V.35, X.21, RS232 EIA TIA-449, EIA-530 Serial V.35, X.21, RS232 EIA TIA-449, EIA-530 Serial V.35, X.21, RS232 EIA TIA-449, EIA-530 A few of the connection options in Figure 3-3 come up on a regular basis Frame Relay Frame Relay connections are serial...

Bandwidth on Demand

Bandwidth on demand (BOD) is a Cisco proprietary implementation that allows the aggregation of multiple B channels into a single logical connection. This implementation is widely used in Cisco-centric networks. The implementation of Cisco's BOD solution is accomplished through the dialer load-threshold command. The variable parameter in the command is load. When the interface is connected to the remote side, a measurement of load is kept and updated continually based on utilization of the link....

Basic Rate Interface

BRI is the most typical ISDN connection and is a native ISDN interface on a router. The basic rate connection consists of two bearer (B) channels and a single (D) channel. When both B channels are active, the aggregate bandwidth becomes 128,000 bps. You can purchase ISDN service with two, one, or zero B channels. Typical deployments use two B channels. Implementations of one B channel provide cost reduction, and zero B channel implementations enable another technology (such as X.25) to be run...

Branch Office Installations

If the installation is to be done in a branch office, there is less need for flexibility than with the central site. This does not mean that a fixed configuration device is acceptable, however. It still might be more palatable for the router to contain enough ports for expansion. Branch office support generally includes access to smaller single function remote offices or remote users. Considerations at the branch office include the WAN connection type and the monthly costs. Additionally, the...

Branch Office Router Selection

Branch office sites are the source of many debates when the time comes to connect them to the central site through a WAN implementation. The amount of bandwidth necessary to adequately support the site is a crucial factor in the decision-making process. The technology implemented to provide the necessary bandwidth is equally important. Consider a small branch office of three users with low bandwidth needs. ISDN BRI might be a good fit for the installation. However, what if the office grows to...

BRI and PRI Basics

ISDN interfaces can be either PRI or BRI. A PRI differs from a BRI mainly due to the number of channels it offers. ISDN channels are usually divided into two different types B and D The bearer channel The B channel is the facility that carries the data. Each B channel has a maximum throughput of 64 kbps. B channels can carry encoded pulse code modulation (PCM) digital voice, video, or data. B channels are used mainly for circuit-switched data communications such as High-Level Data Link Control...

BRI Protocols

As is the standard for implementations in this industry, the ISDN implementation is divided into multiple layers. This division of labor for ISDN is not unlike the OSI model. ISDN has three layers. Layer 1 deals with signal framing, Layer 2 deals with framing protocols, and Layer 3 deals with D channel call setup and teardown protocols. Each of these protocols has a specific mission to accomplish. Figure 6-4 depicts the ISDN layer model.

Central Site Installations

If the installation is taking place in a central or corporate headquarters site, room for growth should be a strong consideration. Room for growth is important because remote or branch sites can be added or deleted over time and the hardware platform should be flexible so that a forklift upgrade is not needed every time a change in corporate strategy occurs. Decisions for the central office should include evaluation of speeds and feeds. The speeds should be sufficient to aggregate the...

Central Site Router Selection

The central site is usually the corporate office site and is also usually the largest of the sites. With this distinction comes the need for more diverse capabilities with regard to WAN connectivity. Many times, multiple technologies must be supported at this site, and all facets of the network must be supported. In addition, each of the branch offices connects back to the central site, and remote and or mobile users need to be able to connect through telephone lines to the network. All of...

Central Site Router Verification

Each router model has its own set of LEDs. They're usually located in the same places. Overall status LEDs, such as Enabled and Active LEDs, are usually on the front of the chassis. The interface specific LEDs are on the back of the chassis, adjacent to the interface in question. The rule with LEDs is simple Green is good. Any other color should be investigated. With the model by model differences in mind for individual routers, this discussion focuses on only a couple chassis models, rather...

Managing Network Performance with Queuing and Compression 291

Do I Know This Already Quiz 292 Configuring WFQ 299 Priority Queuing 300 Configuring Priority Queuing 301 Custom Queuing 306 Configuring Custom Queuing 308 Verifying Custom Queuing 312 Compression Overview 312 Link Compression 314 STAC 314 Predictor 314 Payload Compression 315 TCP Header Compression 315 Compression Issues 316 Configuring Compression 316 Foundation Summary 317 Q& A 319 Scenarios 324 Scenario 10-1 324 Scenario 10-2 325 Scenario 10-3 325 Scenario 10-4 326 Scenario Answers 327...

Scaling IP Addresses with NAT 331

Do I Know This Already Quiz 332 Simple Dynamic NAT Configuration 344 NAT TCP Load Distribution Configuration 349 Foundation Summary 355 Q& A 356 Scenarios 361 Scenario 11-1 361 Scenario 11-2 361 Scenario 11-3 362 Scenario Answers 363 Scenario 11-1 Answers 363 Scenario 11-2 Answers 364 Scenario 11-3 Answers 364

Using AAA to Scale Access Control in an Expanding Network 367

Do I Know This Already Quiz 368 AAA Overview 372 Authentication 372 Authorization 373 Accounting 373 AAA Configuration 374 Enabling AAA 374 AAA Authentication 375 AAA Authentication Login 376 AAA Authentication Enable 377 AAA Authentication ARAP 378 AAA Authentication PPP 379 AAA Authentication NASI 380 Scenario 12-1 393 Scenario Answers 394 Scenario 12-1 Answers 394 Appendix A Answers to the Do I Know This Already Quizzes and Q& A Sections 397

Assembling and Cabling the WAN Components

Do I Know This Already Quiz 44 Choosing WAN Equipment 48 Central Site Router Selection 48 3600 Router Series 49 4000 Router Series 50 AS5X00 Router Series 50 7200 Router Series 51 Branch Office Router Selection 51 1600 Router Series 52 1700 Router Series 52 2500 Router Series 52 2600 Router Series 52 Small Office Home Office (SOHO) Router Selection 53 700 Router Series 53 800 Router Series 53 1000 Router Series 53 Assembling and Cabling the Equipment 54 Available Connections 54 3600 Router LEDs...

Configuring Asynchronous Connections with Modems

Do I Know This Already Quiz 68 Modem Signaling 72 Data Transfer 73 Data Flow Control 73 Modem Control 73 DTE Call Termination 74 DCE Call Termination 74 Modem Configuration Using Reverse Telnet 74 Basic Asynchronous Configuration 78 Logical Considerations on the Router 79 Physical Considerations on the Router 80 Configuration of the Attached Modem 82 Modem Autoconfiguration and the Modem Capabilities Database 82 Chat Scripts to Control Modem Connections 84 Reasons for Using a Chat Script 85...

Using ISDN and DDR Technologies 125

Do I Know This Already Quiz 126 Basic Rate Interface 131 BRI Protocols 133 ISDN Layer 1 133 ISDN Layer 2 135 ISDN Layer 3 138 ISDN Call Setup 139 ISDN Call Release 141 Step 1 Setting the ISDN Switch Type 142 Step 2 Specifying Interesting Traffic 143 Specifying Interesting Traffic with Access Lists 144 Step 3 Specifying Static Routes 145 Step 4 Defining the Interface Encapsulation and ISDN Addressing Parameters 146 Configuring ISDN Addressing 146 Step 5 Configuring Protocol Addressing 147 Step 6...

Configuring a Cisco 700 Series Router 193

How to Best Use This Chapter 193 Do I Know This Already Quiz 194 Foundation Topics 197 Cisco 700 Series Router Key Features and Functions 197 Networking 197 Routing and WAN 198 ISDN and Telephony 198 Cisco 700 Series Router Profiles 198 LAN Profile 199 Standard Profile 199 Internal Profile 199 System Profile 199 Profile Use Guidelines 199 Configuring the Cisco 700 Series Router for IP Routing 200 Profile Configuration Commands for the Cisco 700 Series Routers 203 Profile Management Commands for...

Establishing an X25 Connection 221

Do I Know This Already Quiz 222 X.25 Layered Model 229 X.25 Layer 229 X.121 Addressing 231 LAPB Layer 232 X.25 Physical Layer 233 Step 1 Setting the Interface Encapsulation, Specifying DCE or DTE 234 Step 2 Configuring the X.121 Address 234 Step 3 Mapping the Appropriate Next Logical Hop Protocol Address to its X.121 Address 234 X.25 Configuration Examples 235 Additional Configuration Options 237 Configuring the Range of Virtual Configuring Packet Size 238 Configuring Window Size 238...

Frame Relay Connection Controlling Traffic Flow 251

Do I Know This Already Quiz 252 Understanding Frame Relay 257 Device Roles 257 Frame Relay LMI 258 Issues When Connecting Multiple Sites Through a Single Router Interface 260 Resolving Split Horizon Problems 261 Step 1 Determine the Interface to Be Configured 263 Step 2 Configure Frame Relay Encapsulation 264 Step 3 Configure Protocol-Specific Parameters 264 Step 4 Configure Frame Relay Characteristics 264 Verifying Frame Relay Configuration 266 show frame-relay pvc Command 267 show frame-relay...

Choosing WAN Equipment

Once the goals of the network have been decided on, the hunt for proper equipment begins. Choosing the equipment that goes into each site is always an interesting endeavor. Vendors are contacted, and sales personnel visit and relentlessly tell you that their equipment is the best. Wisely, the decision is made to go with Cisco products (as if there were ever a doubt). Obviously, the needs of each individual site in Figure 3-2 vary. The next few sections focus on each site and its unique...

Cisco 700 Series Router Profiles

The Cisco 700 series router uses different profiles to store the configuration parameters associated with a remote connection or location. This is not unlike the IOS command-line syntax that most engineers associate with an interface dialer on an enterprise-type Cisco router. In a 2500 series router, the phone number, the authentication password, and the addressing could be associated with a dialer interface. The 700 series router, using the same concept, calls the stored information for a...

Compression Issues

Specific issues arise during specific network implementations. In selecting the algorithm that will be utilized for a particular deployment, the following should be considered Modem compression Some modems implement compression. Modems making use of MNP5 and V.42bis are not compatible. Although each offers 2 and 4 times compression, they cannot communicate with each other. If you use modem compression, make sure that the modems at both ends of the connection are using a common protocol. If...

Compression Overview

Various types of compression algorithms are in use in the world today. Many are well conceived and utilized. Others, well, let's just say they're the opposite. For compression, a scope needs to be set ahead of time. There are compression methods for data, links, hard drives, and so on. Our discussion in this chapter focuses on compression across WAN links. Whether data is already compressed when WAN links begin to process it affects the router's capability to further compress that data. If data...

Configuring a Cisco 700 Series Router

The 700 series router was purchased by Cisco from Combinet in 1997. The purchase gave Cisco an ISDN product uniquely suited to the telecommuter and SOHO market. The 700 series provides single Basic Rate Interface (BRI) connectivity and an Ethernet interface for a LAN connection. The 700 series router is compatible with the full Cisco router product line however, it does not use the same command line structure for configuration. The command line of the 700 series router uses set as the main verb...

Configuring Compression

To configure compression, there are a number of commands. Most are technology-specific. The technology-specific commands are not what one would consider intuitive overall. For software compression, use the compress command RouterA(config-if) compress predictor stac mppc For Frame Relay deployments, use the frame-relay payload-compress command to enable STAC compression on an interface or a subinterface. There are no additional configuration parameters for use with this command, as illustrated...

Configuring ISDN Addressing

ISDN addressing uses phone numbers that are exactly like the phone numbers utilized by millions of people day in and day out. These numbers are telco-designated and locally significant. They usually include an area code, a local exchange, and additional digits. To function, the router must understand what phone number to dial as well as when to dial it. How does it come to know this information The same way it knows everything else it knows the administrator tells it. The administrator uses...

Configuring PPP and Controlling Network Access

The CCNP Remote Access Exam requires you to have an in depth understanding of various WAN technologies. In this chapter the discussion focuses on Point-to-Point Protocol (PPP). The typical implementation of PPP has traditionally been in dial-up and or ISDN deployments. The growing need of corporations to include dial-up access to network resources for remote users has created a high demand for point-to-point technologies. Telecommuting personnel require access to network devices and information...

Configuring the Cisco 700 Series Router for IP Routing

There are three sections to configuring a Cisco 700 series router the system level, the LAN, and the user profile. The system profile contains that information that is generally found in the global configuration on an IOS router. The information includes the name of the router and the switch type. Additionally, the system level contains the encapsulation type, the authentication type, and the password used by the 700 series router when it connects to another device. This information is placed...

Configuring X25

The configuration of X.25 is very similar to the configuration of other WAN protocols. It involves the gathering of information that is needed to properly initialize the X.25 interface and enable communication. The following tasks are necessary Step 1 Set the encapsulation of the interface and specify DCE or DTE. If no specification is made, the setting defaults to DTE. Step 2 Configure the X.121 address as assigned by the PDN service provider. Step 3 Map the appropriate next logical hop...

Contents at a Glance

Chapter 1 All About the Cisco Certified Network and Design Professional Certifications 3 Chapter 2 Cisco Remote Connection Products 19 Chapter 3 Assembling and Cabling WAN Components 43 Chapter 4 Configuring Asynchronous Connections with Modems 67 Chapter 5 Configuring PPP and Controlling Network Access 97 Chapter 6 Using ISDN and DDR to Enhance Remote Connectivity 125 Chapter 7 Configuring the Cisco 700 Series Router 193 Chapter 8 Establishing an X.25 Connection 221 Chapter 9 Establishing...

Custom Queuing

Custom queuing enables the sharing of available bandwidth evenly (or not) across all types of traffic. This technique allocates a percentage of bandwidth to each of the various traffic types. The difference between this approach and priority queuing is that the queues are processed in round-robin sequence (in essence, they are multiplexed). Therefore, it is possible that high-priority traffic would not be serviced quickly enough because although each type of traffic would get some bandwidth, no...

Data Transfer

The pins used for data transfer are pin 2, 3, and 7. The DTE device raises the voltage on the RTS when it has buffer space available to receive from the DCE device. Once a call is established and the DTE device sees the DCE raise the voltage on the CTS, the DTE device transmits data on pin 2. Conversely, the DTE device will raise the voltage on the RTS when it has buffer space available to receive from the DCE device. The need for the ground pin is such that a positive or negative voltage can...

DCE Call Termination

If a far-end modem drops the CD because the remote DTE has ended the transmission, the near-end modem must signal the near-end DTE that the transmission has been terminated. The modem must be programmed to understand and signal this termination. In other words, the modem must be told how to handle the loss of carrier detection. By default, most modems understand that this signal loss is an indication that the call is to be terminated. However, it is a configuration parameter that the modem must...

Debug dialer Command

There are many more commands and command outputs that are useful in troubleshooting the dial process in general. For instance, the debug dialer command is one of the best tools to use in figuring out what traffic is attempting to traverse the ISDN link. Example 6-21 shows the debug dialer command output. Example 6-21 debug dialer Command Output SYS-5-CONFIG_I Configured from console by console Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 10.12.1.2, timeout is 2 seconds BRI0...

Dedicated and Interactive PPP Sessions

Asynchronous interfaces on an access server can be configured to accept inbound calls from remote users. There are two modes that can be used in this situation, interactive and dedicated. In interactive mode, users who dial into the network are able to access the user mode prompt. The user must enter the command ppp connect to initiate the connection. If access to the router prompt is unacceptable, dedicated mode should be used. Dedicated mode forces the connection into a PPP session once the...

Default Routes

From time to time, a router is faced with a dilemma that it would dread (if it could dread, that is). The dilemma is what to do when it doesn't know what to do. As it stands now, in the absence of a suitable routing table entry to a given destination, a router has no choice but to return an ICMP Destination Unreachable message to the sender. This dilemma, however, is easily remedied. By giving the router a default route, it can forward the traffic on to another router that may have a suitable...

Defining Additional Interface Information

The purpose of DDR is to bring down the ISDN link when the traffic volume is low or idle. However, at times, the traffic volume can simply be in a short lull. Indeed, LAN traffic is bursty quiet times followed by an explosion of traffic. To avoid the link coming down when traffic flow ceases and then being forced to redial, use the dialer idle-timeout command. Executing this command dictates that when traffic defined as interesting has ceased to flow across the link for the specified period of...

Device Roles

Frame Relay devices fall into one of two possible roles, data terminal equipment (DTE) or data circuit-terminating equipment (DCE). DCE is sometimes known as data communications equipment as well. Both terms are correct. It is important to understand that the DTE DCE relationship is a Layer 2 (data link) layer relationship. DTE and DCE relationships are normally electrical (that is, Layer 1). The DTE DCE relationship at Layer 1 is independent of that at Layer 2. In other words, just because a...

DHCP Overview

DHCP provides a method for automatically assigning reusable IP addresses to clients. Cisco's implementation of DHCP follows RFC 2131 for DHCP concepts and RFC 2131 for DHCP options. The 700 IOS DHCP server gives the SOHO administrator a much simpler IP address management scheme. DHCP enables the small office with the capability to provide IP addressing on an as-needed basis for each local client. This method eliminates address management on a PC-by-PC basis, which reduces client configuration...

Dial Backup

In Example 6-25, notice the backup delay 5 60 command, which specifies that if there is a failure, the system should wait five seconds to bring up the backup link. Once the failure has passed, the system should wait 60 seconds to bring the backup link back down. Example 6-25 Dial Backup Example Configuration RouterA(config) isdn switch-type basic-5ess RouterA(config-if) ip address 10.14.1.1 255.255.255.0 RouterA(config-if) encapsulation hdlc RouterA(config-if) backup interface BRI0...

Do I Know This Already Quiz

The purpose of the Do I Know This Already quiz is to help you decide what parts of this chapter to use. If you already intend to read the entire chapter, you do not necessarily need to answer these questions now. The twelve-question quiz helps you determine how to spend your limited study time. The quiz is sectioned into smaller, two-question quizlets, each of which corresponds to the six major topic headings in the chapter. Use the scoresheet in Table 4-1 to record your scores. Table 4-1...

DTE Call Termination

When the DTE is ready to terminate the connection because the user has completed the call and signaled the PC to go back on-hook, the DTR is dropped. For this to happen, the modem must be configured to interpret the loss of the DTR as the end of a conversation. When the DTE drops the DTR, the modem is alerted that the carrier is no longer needed. This configuration is done when the modem is first installed. This can be manually done for each call, or it can be scripted in a chat script that is...

Dynamic NAT Configuration

The simplest form of configuration is a one-to-one translation in which the IP address of the Inside Local address in the network header is replaced by an Inside Global address. The replacement can be done statically or dynamically. Example 11-1 shows a simple NAT translation with the assignments done dynamically. The following conditions dictate the use of NAT translation Only on interfaces that are declared inside or outside can packets be translated. Only traffic from an outside to an inside...

E1 Framing

E1 is based on the same basic foundation as T1. The concept of 64-kbps timeslots created by 8000 eight-bit samples per second still holds true, and the sampling rates and methodologies between T1 framing and E1 framing are very similar. The differences lay in the assembly and multiplexing of the channels. E1 frames are constructed of 30 timeslots. Therefore, each E1 frame contains 30 eight-bit samples. When 16 E1 frames are assembled, a multiframe is created. MultiFrame is the dominant frame...

E1 Line Code

E1 deployments can implement AMI however, the issues with AMI and data transmission still hold true data transmissions are limited to 56 kbps. To remedy this, high-density bit, level 3 (HDB3) was created. It operates similarly to B8ZS, but in a slightly more efficient manner. If a long string of 0s is detected, a number of them are changed to 1s for the duration of their trip across the provider network. They are then changed back to their original values at the remote CSU DSU. Obviously, T1 E1...

Establishing an X25 Connection

The CCNP Remote Access Exam requires you to be familiar with the implementation options associated with X.25. You must understand the basic deployment of X.25 as well as the optional configuration parameters. X.25 is similar in some respects to ISDN. The basic functionality of the two is based on the same technology, and the Public Switched Telephone Network (PSTN) still provides the necessary switching facilities. X.25 is similar not only to ISDN for switched virtual circuits (SVCs) but also...

Feedback Information

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Fifo

FIFO is the most basic of strategies. In essence, it is the first-come, first-served approach to data forwarding. In FIFO, packets are transmitted in the order in which they are received. Until recently, FIFO was the default queuing strategy for all interfaces on a router. However, should it become necessary for the traffic to be reordered in any way, another strategy must be invoked because FIFO gives no regard to one type of traffic over another. It simply dispatches data as it receives it....

Foundation Summary

Overall, this chapter dealt with physical connectivity for the router. Most cables are interface-specific in that they can be attached at only one place on the router. That is not always the case, however. For example, Category 5 UTP cable can be used with Ethernet, T1 E1 WIC, and ISDN interfaces. You should take the time to ensure that the correct cable is attached in the appropriate place. A straight-through Ethernet cable does not work in a T1 E1 WIC connection. The pinouts are dissimilar....

Foundation Topics

The discussions in this chapter revolve around a fictitious, albeit typical, network topology. Figure 3-2 depicts that topology. Figure 3-2 Network Topology for Chapter Discussion Figure 3-2 Network Topology for Chapter Discussion Figure 3-2 depicts a number of technologies in the network. These technologies (ISDN, Frame Relay, X.25, and so on) are discussed in this book at various times and are not discussed in this chapter. You must understand the concepts and components involved in properly...

Foundation Topics AAA Overview

AAA provides a method for setting up access control on a router. Access control provides a means to declare who (authentication) can access the network, what (authorization) the users can do, and what (tracking or accounting) the user has done. AAA provides a method to control and configure these three independent security functions. CiscoSecure ACS (Access Control Server) provides authentication, authorization, and accounting and is used in many of the BCRAN classes as the AAA server. This...

Foundation Topics Cisco 700 Series Router Key Features and Functions

The key features of a 700 router are Internet access for multiple users over one ISDN line The Cisco 700 series router enables multiple PCs to access the Internet simultaneously. This keeps users from having to share a single PC with an Internet connection or rely on server-based hardware and software. A single Cisco 700 series router can make everyone in the office more productive. Affordable Internet connections for SOHOs With the Cisco 700 series, there's no need to install a separate ISDN...

Foundation Topics Modem Signaling

This chapter covers the signaling of the modem and the configurations for a Remote Access Server (RAS) connection. The successful CCNP or CCDP candidate should be able to describe the signaling and pins used by the cabling and not just the syntax that is required for the connection. The signaling is just as important because it provides the basis for the physical-layer troubleshooting that can be needed to establish a connection. Asynchronous data communications technology occurs when an end...

Foundation Topics PPP Background

PPP's basic function is to encapsulate network layer protocol information over point-to-point links. The mechanics of PPP are as follows Step 1 To establish communications, each end of the PPP link must first send Link Control Protocol (LCP) packets to configure and test the data link. Step 2 After the link has been established and optional facilities have been negotiated as needed, PPP must send Network Control Protocol (NCP) packets to choose and configure one or more...

Foundation Topics Understanding Frame Relay

Frame Relay is a connection-oriented, Layer 2 networking technology. It operates at speeds from 56 kpbs to 45 Mbps. It is very flexible and offers a wide array of deployment options. Frame Relay operates by statistically multiplexing multiple data streams over a single physical link. Each data stream is known as a virtual circuit (VC). Frame Relay VCs come in two flavors, permanent and switched. Permanent Virtual Circuits (PVCs) are, just as the name implies, permanent, nailed up circuits. They...

Frame Relay Configuration

The basic configuration of Frame Relay is quite simple. In many cases, the configuration can be as simple as setting the encapsulation and putting an IP address on the interface. This enables inverse-ARP to dynamically configure the DLCI and discover neighboring routers across the cloud. However, configurations are rarely that simple. Although basic functionality can be achieved in this manner, more complex procedures are necessary for hub and spoke subinterface configurations dealing with...

Frame Relay Connection Controlling Traffic Flow

The CCNP Remote Access exam requires you to have an in depth understanding of various WAN technologies. This chapter discusses the basics of Frame Relay as well as how to tweak it to maximize traffic control and throughput. Although Frame Relay is not a new technology by any means, it is still widely implemented around the world. Even with the advent of newer (and faster) broadband technologies, Frame Relay continues to remain popular in the workplace. Frame Relay is a high-performance WAN...

Frame Relay LMI

Local Management Interface (LMI) is the means by which Frame Relay edge devices maintain keepalive messages. The Frame Relay switch is responsible for maintaining the status of the CPE device(s) to which it is attached. LMI is the communication by which the switch monitors status. LMI implements a keepalive mechanism that verifies connectivity between DCE and DTE and the fact that data can flow. A LMI multicast capability, in conjunction with an LMI multicast addressing mechanism, enables...

Frame Relay Topologies

Frame Relay supports connectivity of remote sites through one of three topological strategies. Each has its own advantages and disadvantages, as pointed out in the following list Hub and spoke Also known as the star topology, this is the dominant method of deploying Frame Relay. It consists of a single central site acting as a connection point for all remote offices. Routing between two satellite offices is accomplished through the central site. Routing through the central site tends to be the...

Frame Relay Traffic Parameters

To properly understand the concepts of traffic shaping, it is important to have a firm grasp of the various traffic parameters in the Frame Relay Network. In particular, you should know that some (such as CIR and Be (Excessive Burst)) are commonly used, but misunderstood. Table 9-2 details the traffic parameters. Table 9-2 Frame Relay Traffic Parameters The average rate you want to transmit. This is generally not the same as the CIR provided by the telco. This is the amount you want to send in...

Frame Relay Traffic Shaping

Frame Relay traffic shaping is a means of controlling the output of traffic across the Frame Relay network. Whether the goal is to meet service contract obligations or to control output speed to slower links, traffic shaping can provide granular control of outbound data. Traffic shaping can provide per-VC rate enforcement, BECN support, and queuing (WFQ, PQ, or CQ) at the VC level. Frame Relay traffic shaping is supported only on fast switching and process switching paths. Therefore, to use it,...

Frame Relay Traffic Shaping Configuration

Frame Relay traffic shaping is accomplished through the creation of a map class. This map class can be associated with one or more PVCs. The map class defines the traffic parameters for any circuits to which it is applied. The command structure for defining the map class is as follows RouterA(config) map-class frame-relay name The name parameter is an arbitrary value. This is the parameter that is used to tie the map class to one or more PVCs. Once the map-class command has been entered, the...

Hardware Selection

When the research is done and the location is selected, the last step is to select a router that meets the specifications created. Cisco is continually updating the product line for all types of WAN scenarios. The best way to stay current with the offerings available for RAS solutions is at the Cisco web site at www.cisco.com. The products in the following section represent some of the current offerings for Remote Access environments. The successful CCNP or CCDP candidate should be aware of the...

How to Best Use This Chapter

By taking the following steps, you can make better use of your study time Keep your notes and answers for all your work with this book in one place for easy reference. Take the Do I Know This Already quiz and write down your answers. Studies show retention is significantly increased through writing facts and concepts down, even if you never look at the information again. Use the diagram in Figure 2-1 to guide you to the next step.

How to Use This Book to Pass the Exam

There are five sections in each chapter a short pre-assessment quiz, the main topics of the chapter, a summary of the key points of the chapter, a test to ensure that you have mastered the topics in the chapter, and finally (when applicable), a scenario section with scenario-related questions and exercises. Each chapter begins with a quiz, which is broken into quizlets. If you get a high score on these quizlets, you might want to review the Foundation Summary section at the end of the chapter...

Implementing Basic DDR

Dial-on-demand routing (DDR) is a feature available on ISDN-capable Cisco routers. It was created to enable users to save money on usage-based ISDN. Use-based ISDN occurs when charges are assessed for every minute of ISDN circuit connect time. Obviously, in a charge-by-the-minute scenario, the connection should be down during no or low-volume traffic times. DDR provides that capability and offers a wide array of commands and configuration variations. Many of those configuration options are...

Interface Types

An understanding of the communication method on each port or port definition is important to understanding and performing a successful configuration of AAA. Character mode is used on the TTY, VTY, AUX, and CON ports. These are the control ports on the router. On the other hand, packet mode is used on the async, group-async, BRI, PRI, serial, dialer profiles, and dialer rotaries. These are the communication ports on the router. The concept of control versus communication is a fine distinction....

ISDN and Telephony

The 700 series router provides dial tone for the telephone service on plain old telephone service (POTS) RJ-11 interfaces. On the earlier 700 series models (750 760), the model number defined the ISDN interface type. The 700 series models that ended in an even number provided the built-in network termination 1 (NT1) interface for ISDN. The models that ended in an odd number provided an S T interface, for which the customer had to supply the NT1 device if it was needed. In the United States, the...

ISDN Call Release

Any party in the network can release the call for whatever reason. Whether the release of the call is intentional or accidental (that is, due to some type of failure in the network), the call is torn down completely. When either the calling or called party is ready to disconnect a call, that party issues a disconnect (DISC) message. The disconnect is not negotiable. If necessary, the call can be re-established, but once a disconnect is issued, the call comes down. When a DISC is issued, it is...

ISDN Layer

The Layer 2 processes of ISDN are defined in the ITU specifications Q.920 and Q.921. Q.921 defines the actual communication format. Obviously, Layer 2 communication does not take place unless Layer 1 is properly installed and functioning. Q.921 institutes an addressing scheme similar to many other networking technologies. Just as in LAN implementations, ISDN Layer 2 addressing is meant to provide physical addressing on the network. Because multiple logical devices can exist in a single physical...

Issues When Connecting Multiple Sites Through a Single Router Interface

When a single physical interface is utilized on a central router to connect multiple remote sites, routing problems arise. These problems are caused by split horizon. Split horizon is a rule in routing protocol operation that is designed to eliminate routing loops by not allowing routing updates to be sent out of the interfaces through which they were received. Consider the situation in which one serial interface serves multiple remote sites. In this scenario, split horizon effectively shuts...

Know This Already Quiz

The purpose of the Do I Know This Already quiz is to help you decide which parts of this chapter to use. If you already intend to read the entire chapter, you do not necessarily need to answer these questions now. The six-question quiz helps you determine how to spend your limited study time. The quiz is sectioned into smaller quizlets, each of which corresponds to the four major topic headings in the chapter. Use the scoresheet in Table 2-1 to record your scores. Table 2-1 Scoresheet for...

Link Compression

Link compression (also known as per-interface compression) is the compression of the entire transported entity. In other words, it compresses the header and the payload. Link compression is not dependent on any particular protocol function. Cisco supports two algorithms on its router chassis to compress traffic STAC and Predictor. For HDLC links, STAC is the only available choice. For data transmission over point-to-point dedicated connections, use link compression. In link compression, the...