B

B channels (ISDN), displaying status, 375 baselining, 41 Notification), 313 BRI (Basic Rate Interface) interface D channel, 351 Layer 1, 352 PUP timer, 353-354 T3 timer, 353-354 Layer 2, 355, 357 activating, 358-360 INFO frames, 360 LAPD frame format, 357 RR messages, 359 Layer 3, 365, 367 call rejection, 371 SPID numbers, 369-371 Browser service (Windows), Cisco 7000 series routers, 130-132 sizes of, 129 Bug Toolkit (CCO), 18-19 distance limitations, 246-247 testers, 6 troubleshooting, 246...

Book Layout

This final section of the introduction covers briefly the contents of each chapter in the book. Chapter 1 covers three main topics. First, it lists and introduces you to a number of troubleshooting tools that are adequate for testing different aspects or components of an internetworking model. You must learn when and why each tool is used, and what information may be obtained from each. Next, Cisco Connection Online is introduced. You should know who can access CCO and how. Familiarity with the...

Buffers and Queues

System buffers are memory allocated from main system memory (also referred to as shared memory) to hold packets while they are process-switched. There are parameters regarding these buffers that can be tuned, but that is not often recommended, and tuning them has no effect on any route caching methods you may have (fast, autonomous, silicon, or optimum switching, for instance). To enhance the (packet) processing power of your router, you are usually encouraged to take advantage of your router's...

Buffers and Queues Cisco 70007010

In the Cisco 7000, routers' packets are held in interface hardware buffers, SP or SSP buffers, and RP buffers. Figure 4-6 displays those Cisco 7000 router components along with the error conditions associated with each of them. Figure 4-6 Cisco 7000 Buffers and Error Conditions Interface input and output queues on the RP are linked lists of processor buffers used for each interface. An interface queue can hence be composed of different-sized buffers. The queue associated with an interface can...

Cable Speed and Media Concerns

The link LED on each individual port of the Catalyst 5000 switch is of great value to you. If this LED, which is often referred to as port integrity LED, is not green on both sides of a connection, you have a problem. If either side is not powered up, has the port disabled, or does not have the cable properly inserted, or if the cable is simply broken, substandard, badly bent or otherwise abused, the link integrity LED does not come on. Hence, checking to make sure that both sides of a link...

CCNP Support Exam Certification Guide

CCNP Support Exam Certification Guide Copyright 2001 Cisco Systems, Inc. Cisco Press logo is a trademark of Cisco Systems, Inc. Published by Cisco Press 201 West 103rd Street Indianapolis, IN 46290 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...

CCO Bug Toolkit

The Bug Toolkit is a set of tools including the Bug Navigator II, Bug Watcher, and watcher agents, all of which are made available to registered users on CCO from one place www.cisco.com support bugtools (see Figure 1-7). If you experience abnormal behavior in your network, or are thinking of upgrading your IOS, you can search for reported defects based on IOS version release number or keywords related to the symptoms you have observed or the technology you are concerned with. Next, you can see...

CCO Open Forum

The CCO Open Forum (www.cisco.com openf ), as the name implies, is an online Q& A facility that Cisco Systems has provided for its customers. If you have a technical question that relates to Cisco Systems products (hardware or software), you can use the Open Forum (see Figure 1-9) to look for your answer in two ways By searching the existing Q& A database By submitting your question to the Open Forum (if you could not find your answer in the current database) As is indicated in the Open...

CCO Stack Decoder

Stack Decoder (see Figure 1-8) is another troubleshooting tool available at CCO (www.cisco.com stack). This tool is used when a router crashes it decodes the stack trace generated by Cisco routers and switches. If you execute the privileged command show stack from the exec prompt of the router, the stack trace appears. Next, you can paste the results in the input field of the Stack Decoder page. Stack Decoder decodes the stack trace and creates a symbol file. The symbol file (perhaps along with...

Cisco Discovery Protocol

Cisco Discovery Protocol (CDP) is a Cisco proprietary layer 2 (data link layer) protocol that is bundled in Cisco IOS release 10.3 and later versions. This protocol can run on all Cisco manufactured devices including routers, switches, hubs, bridges, and communication servers. CDP uses SNAP (layer 2 frame type) and it is multicast based, utilizing the Cisco multicast address 0100.0ccc.cccc as the destination address on the frame header. Because a Cisco device running CDP periodically sends...

Cisco Press Fundamentals

IP Routing Primer Robert Wright, CCIE 1-57870-108-2 AVAILABLE NOW Learn how IP routing behaves in a Cisco router environment. In addition to teaching the core fundamentals, this book enhances your ability to troubleshoot IP routing problems yourself, often eliminating the need to call for additional technical support. The information is presented in an approachable, workbook-type format with dozens of detailed illustrations and real-life scenarios integrated throughout. Allan Leinwand, Bruce...

Cisco Press Solutions

EIGRP Network Design Solutions Ivan Pepelnjak, CCIE 1-57870-165-1 AVAILABLE NOW EIGRP Network Design Solutions uses case studies and real-world configuration examples to help you gain an in-depth understanding of the issues involved in designing, deploying, and managing EIGRP-based networks. This book details proper designs that can be used to build large and scalable EIGRP-based networks and documents possible ways each EIGRP feature can be used in network design, implmentation,...

Cisco Routers Routing Processes and Switching Processes

Routing and switching processes are two of the most essential tasks performed by routers. Some people in the internetworking field have a little difficulty with the idea that routers perform switching, but of course everybody is comfortable with the fact that routers perform routing. Nonetheless, as you will see, the distinctions between these operations will be quite useful in optimizing the router's performance. In the following paragraphs the concepts of routing and switching are defined. A...

Clearing Interface Counters

If you suspect interface problems, the output of the show interfaces command gives you a great amount of information about the state of the interface (physical and logical) and also some statistics about the data sent and received, errors encountered, and so on. Consider Example 3-1 for this discussion. Seriall is up, line protocol is up Hardware is HD64570 MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usee, rely 255 255, load 1 255 Encapsulation FRAME-RELAY, loopback not set, keepalive set (10 sec)...

Common Apple Talk Trouble Symptoms Possible Causes and Suggested Actions

This section concentrates on common errors and misconfigurations related to AppleTalk settings, the expected symptoms of each problem, and how you can identify the exact reason for the symptoms and rectify the situation. The most common faults found in AppleTalk networks are Configuration mismatch Neighboring routers do not have identical specifications for the cable range and zone name(s) of the segment they have in common. Duplicate cable range network numbers or overlapping cable ranges in...

Contents at a Glance

Support Resources for Troubleshooting 3 Understanding Troubleshooting Methods 33 Identifying Troubleshooting Targets 49 Applying Cisco Troubleshooting Tools 101 Diagnosing and Correcting Campus TCP IP Problems 159 Diagnosing and Correcting Novell Networking Problems 189 Diagnosing and Correcting AppleTalk Problems 215 Diagnosing and Correcting Catalyst Problems 241 Troubleshooting VLANS on Routers and Switches 285 Diagnosing and Correcting Frame Relay Problems 307 Diagnosing and Correcting ISDN...

Debug apple Commands

Using debug commands requires special attention. You should try to use the debug apple commands when the traffic in your network is low. Some debug commands can produce a large amount of output hence, you are encouraged to do events debugging when you can. Example 7-10 displays the debug apple options. This section contains brief explanations for the following significant debug apple commands Please note that the keywork apple used with the debug commands listed is not a truncated form of...

Debug framerelay lmi

When you execute the debug frame-relay lmi command, you should see the status enq. (inquiry) that your router sends out every 10 seconds and the status message (type 1) that your router receives (in) from the Frame Relay switch every 10 seconds (see Example 109). Also, every 60 seconds the switch sends a FULL LMI message to your router (type 0), which includes a list of PVC DLCIs along with the status of each DLCI and its corresponding CIR (Committed Information Rate). The status of each DLCI...

Debug IP Commands

There are many debug IP commands that can be used during the course of a troubleshooting project (see Example 5-6). You must keep in mind that some of the debug commands generate a lot of output, and that usage of the debug command requires special handling (as discussed in Chapter 4, Applying Cisco Troubleshooting Tools). Use the Debug reference manual (also available on Cisco Connection Online CCO and the Documentation CD) for the IOS version you work with. To display the state of each...

Debug ip igrp events

Debug ip igrp events ip-address This debug command displays summary information on sent and received Interior Gateway Routing Protocol (IGRP) routing messages (see Example 5-10). The source and destination of each update as well as the number of routes in each update are indicated for each message. This command does not display the actual IGRP routing entries that are exchanged. If you specify the IP address (optional) of a neighbor router (which is an IGRP peer), IGRP event debugging will only...

Debug ip ospf

The debug ip ospf command is used with one of the following options adj, events, flood, lsa-generation, packet, retransmission, spf, or tree (see top portion of Example 5-13). The debug ip ospf command with the events option displays information on OSPF (Open Shortest Path First) events, such as adjacencies, flooding information, designated router and backup designated router election, and shortest path first (SPF) calculation. Sample output of the debug ip ospf events is shown in the bottom...

Debug ip packet

Debug ip packet detail access-list-number The debug ip packet command is useful for analyzing the flow of IP packets traveling between IP hosts. IP debugging information includes packets received, generated, and forwarded. As discussed in Chapter 4, you have the option to specify an access list number or name after the debug IP packet command to limit the scope of debug output (see Example 5-7). Example 5-7 Various debug IP Examples < 1-199> Access list < cr> events RIP protocol events...

Debug ip rip

This debug command displays information about RIP routing transactions. You may specify the events optional keyword if you are only interested in seeing RIP protocol events. Example 5-9 shows updates being received (RIP version 1) from a router with source address 131.1.18.14. The router being debugged also sent updates, in both cases to broadcast address 255.255.255.255 as the destination. Note that if an interface's broadcast address is modified, then information such as distance vector...

Debug ipx routing

The debug ipx routing command is used with one of the activity or events options, and it displays information on IPX-related routing (RIP) traffic that the router generates and also receives (see Example 6-9). Use this debug command when you are interested in seeing the IPX routing information your router sends out of and receives from each interface. Example 6-9 debug ipx routing Command activity IPX RIP routing activity events IPX RIP routing events

Debug span tree and debug span events

The debug span command can be used with either the tree or the events parameter. The events option is more user-friendly because it tells you in words the meaning of the BPDU packets that the router is receiving (see Example 9-7). The tree option, on the other hand, displays each BPDU received from each interface in its raw format. For instance, the first entry in the output of the debug span tree (Example 9-7) shows the following line 00 15 42 ST Fa0.100 00000080. This line tells you that at 3...

Debug vlan packets

The debug vlan packet command displays messages about virtual LAN (VLAN) packets that the router receives (off the trunk connection) but is not configured to support (see Example 9-6). In other words, if an ISL packet with a VLAN ID of 6 is received, but none of the subinterfaces of the input interface are configured for VLAN 6, the router cannot process the encapsulated frame and the debug process displays a message indicating what has just happened. As mentioned earlier, you may use the show...

Do I Know This Already Quiz

1 True or false The routers that are connected to a single cable segment must have identical settings with regard to network number cable range and zone name(s) of that segment. True. A Cisco router's AppleTalk interface will not become active on a network segment if the zone name(s) and cable range it is configured with do not agree with those of other devices on that segment. 2 True or false In an AppleTalk network, a network number or cable range does not have to be unique. False. In other...

E

EIGRP (Enhanced Interior Gateway Routing Protocol), troubleshooting, 174 embedded RMON agent, Catalyst 5000 switches, 245 encapsulation frame relay command, 311 encapsulation isl command, 290 end-to-end circuits, ISDN, 372 PPP over B channel, 374-376 end-to-end connections (Frame Relay), troubleshooting, 317-319 error messages AppleTalk, debugging, 225-226 logging, 117-120 establishing connections AppleTalk, 82 Novell, 80 TCP, 78-79 Ethernet interfaces, troubleshooting, 54-61 evaluating links,...

Error Message Logging and Limiting the Display of Error Messages

Logging messages are important sources of information for network engineers in charge of troubleshooting. This section covers the following topics The options for the logging messages destination Which destinations are the default for logging messages Which commands enable disable different destinations How usage of different logging destinations compares with regard to the overhead they introduce on the routers The eight levels of logging Deciphering the logging messages Message logging is...

Foundation Summary

The Foundation Summary is a collection of quick reference information that provides a convenient review of many key concepts in this chapter. For those of you who already feel comfortable with the topics in this chapter, this summary helps you recall a few details. For those of you who just read this chapter, this review should help solidify some key facts. For any of you doing your final prep before the exam, these tables and figures are a convenient way to review the day before the exam....

Frame Relay Problem Isolation

To check diagnose a Frame Relay connection, you must perform the following tests (using the troubleshooting commands you have learned) in sequence Check the status of your router's (Frame Relay) serial interface (for example, Serial 1 interface) using the show interface serial n command. The output must show If serial 1 is down, you must check and correct the connection between your router's serial interface and the CSU. If the serial interface is up and the line protocol is down, either the...

N

Navigating Cisco Documentation CD-ROM, 16 NBP (Name Binding Protocol), debugging, 226 nbtstat command, 178 NCP (Novell Core Protocol), 80 NetBIOS cache, displaying, 178 Netflow switching, 112 Netsys, 13 network management systems. See NMSs network maps, STP, 294 network monitors, 7 Network Neighborhood Browser service, troubleshooting, 180 network protocols, characteristics, 77 networks baselining, 41 media testing equipment, 6 modeling simulation tools, 13 NMSs (Network Management Systems), 10...

Network Monitors

Network monitors were first built to capture, display, and save traffic going through a network cable. Since frames are captured, and the information gathered and displayed is pertaining to the data link layer, this tool is considered a Layer 2 tool. Of course, many vendors created different brands and models of this tool with different capabilities. The most common feature of network monitors is their ability to take the raw data and provide some summarization and statistics for the user....

Ping Command IP User and Privileged

The ping command is supported at the user and privileged exec modes.When used at the user mode, a set of default parameters such as five echoes, 100 bytes each with two-second time-outs will be used (in non-verbose form). You may enter an IP address or a name with the ping command (if the name can be resolved to an IP address using the local HOSTS table or using a DNS server). Ping sends ICMP echo (echo request) to the destination, and the destination node replies to the source with an ICMP...

Ping for IPX

Cisco introduced ping for IPX with IOS release 8.2. Ping for IPX has the same usage as ping for IP they both are great reachability testing tools. Novell Corporation also offered ping for IPX with the NetWare IPX SPX protocol stack. However, these two ping for IPX implementations are not compatible. In other words, you cannot use the Cisco IOS ping command to test network layer reachability to devices running Novell's IPX SPX stack (a Novell server, for instance). However, in addition to the...

PPP over B Channel

Before PPP starts delivering upper layer protocol packets between two devices, it goes through a series of negotiations regarding link options and network protocols. The PPP frame format is shown in Figure 11-6. During link options negotiation, the PPP frame's protocol number is 0xC021 (LCP). LCP negotiates link options such as Authentication, Multilinking, Callback, Compression, and line Quality Protocol. For a link option to be implemented, both parties must agree on it. Disagreement on a...

Qa

The answers to the following questions can be found in Appendix A. Some of the questions in this section are repeated from the Do I Know This Already Quiz so that you can gauge the advancement of your knowledge of this subject matter. 1 Write the title of each of the systematic troubleshooting method's steps in the appropriate box on the diagram below 2 Explain the importance of using a systematic troubleshooting method. 3 What are the general tasks performed during the problem definition step...

Reported Conditions

Ignored The number of packets ignored is shown in the output of the show interfaces command. If a buffer (on the interface hardware) gets full, an ignore is registered. In other words, every time an interface cannot accept a frame due to the input buffer being full, the ignore counter is incremented by one. Dropped The number of dropped packets is shown in the output of the show interfaces command. If the input or output queue of an interface reaches its maximum size, the queue cannot grow...

Review of ISDN Troubleshooting Commands

Figure 11-7 displays some of the commands that are used for ISDN troubleshooting. This figure also illustrates which commands are more appropriate for testing specific segments of the ISDN connection (or layer). You are advised to study this figure thoroughly. Figure 11-7 Review of ISDN Troubleshooting Commands debug serial interface debug bri-interface debug ppp negotiation debug isdn q931 debug ppp chap

S

Seed metric, applying to routing protocols, 180 Service Profile Identifier numbers. See SPID numbers set command (Catalyst), 254 set vtp command, 251 severity of logging messages, 120 show appletalk access-lists command, 221 show appletalk adjacent-routes command, 221-222 show appletalk arp command, 222 show appletalk globals command, 222, 228 show appletalk interface command, 219 show appletalk name-cache command, 223 show appletalk neighbors command, 223 show appletalk route command, 220 show...

Show appletalk arp

The show appletalk arp command displays all the entries of the AppleTalk ARP (Address Resolution Protocol) cache. Example 7-6 displays a sample output of this command. Notice that each ARP entry comprises an AppleTalk address, age, type, hardware address, encapsulation (frame type), and the router interface through which the address was learned. Example 7-6 show appletalk arp Command Output

Show appletalk route

The show appletalk route command displays the AppleTalk routing table (see Example 7-3). The routing table displayed in Example 7-3 was obtained from a router called A_BackR connected to a network similar to the one shown in Figure 7-1. If you specify a network number with this command, only the routing table entry corresponding to that network will be displayed. If you specify an interface type and number after the show appletalk route command, only those networks that can be reached through...

Show buffers Command

The show buffers command displays information (statistics) on buffer elements, public buffer pools, and interface buffer pools. Buffer elements are small data structures that are used for internal operating system queues or when a buffer must be associated with more than one queue. The public buffer pools are presented in the second section of the show buffers output and each buffer size (small, middle, and so on) is presented with its own statistics. The last section of the show buffers...

Show framerelay lmi [interface

This command displays LMI statistics about the interface under investigation. If you do not use the interface parameter, this information will be displayed for each and every Frame Relay interface (see Example 10-3). Example 10-3 A Sample Output of the show frame-relay lmi Command LMI Statistics for interface Serial1 The first line of this command's output tells you of the role of the router's serial interface (DTE UNI or NNI) and the LMI type it is configured for (UNI is the acronym for User...

Show framerelay pvc

The show frame-relay pvc command lists all of the PVCs that the router is aware of on all of its Frame Relay interfaces (and subinterfaces), along with their status, creation time, last status change time, and statistics regarding the sent received packets bytes and the congestion notification flags (see Example l0-5). Example 10-5 A Sample Output of the show frame-relay pvc Command PVC Statistics for interface Serial0 (Frame Relay DTE) LOCAL, PVC STATUS ACTIVE, INTERFACE Serial0 23, last time...

Show ip Commands

This section covers various show commands and explains their purpose and output. The following commands are covered This command lists a summary of an interface's IP information and status. Example 5-1 displays a sample output of the show ip interface ethernet 0 command. Example 5-1 show ip interface ethernet 0 Command Output A_StubR show ip interfaces ethernet 0 Ethernet0 is up, line protocol is up Broadcast address is 255.255.255.255 Directed broadcast forwarding is enabled IP fast switching...

Show ip protocols

This command displays the parameters and current state of the active routing protocol(s) (see Example 5-5). When troubleshooting IP routing cases, this command is often used to see which routing protocols are active, what their AS-number(s) or process-id(s) are, which networks they are configured for, if they are redistributing any routing information, and if there are any filters active for the routing protocols. Example 5-5 show ip protocols Command Output Sending updates every 90 seconds,...

Show ipx nlsp

NetWare Link Services Protocol (NLSP) is a link state routing protocol you may use for IPX routing. This protocol may be activated with or without a process tag. A process tag is useful in cases where you must run multiple copies of the NLSP process on the same router. The show ipx nlsp process-tag command must be used with one of the following parameters database, neighbors, or spf-log (see Example 6-7). This command is a specialized command that assists you in obtaining information about the...

Show span [vlannumber

This command first appeared in Cisco IOS Release 10.3 and it shows the Spanning-Tree Protocol information known to the router (see Example 9-3). The first part of this command's output shows the type of Spanning-Tree Protocol in use, the bridge ID (priority and address) of the local device (the router), the ID of the root device, and the timer parameters of the spanning tree. Next, the interfaces that participate in the spanning tree (associated to the VLAN number typed in) are listed. For each...

Show stacks Command

Show stacks is an exec command that is commonly used to diagnose system crash situations. The first section of this command's output displays stack utilization of processes and interrupt routines, and the reason for the last system reboot. When a system crash happens, failure type, failure program counter (PC), address (operand address), and a stack trace are saved by the ROM Monitor. The show stacks command displays the data saved by the ROM Monitor. The stack trace is displayed in the second...

Switching in 7000 Series Routers

The 7000 series routers, similar to other Cisco routers, have a fast switching option that is enabled by default. Fast switching is performed using a Fast Switch Cache in the Route Processor. Two major components that participate in the routing and switching operations are RP (Route Processor) and SSP (Silicon Switch Processor). The early models of the 7000 series had RP and SP (Switch Processor). The SP (in the earlier models) only had an Autonomous Switch Cache. The SSP was introduced later...

Switching in 7500 Series Routers

To enhance the performance and efficiency of its high-end routers, Cisco Systems made some major improvements in the 7500 series routers The internal bus of the 7500 series router (CyBus) operates at1 Gbps, which is about twice as fast as the 7000 router's CxBus. Instead of having two separate components for routing and switching (SSP and RP) as in 7000 routers, the 7500 router is equipped with one component called the Route Switch Processor (which eliminates the slow 153 Mbps system bus...

The show appletalk traffic Command

The show appletalk traffic command displays AppleTalk traffic information, as shown in Example 3-10. The output displays information such as the number of packets sent and received, various errors encountered, and a classified set of statistics on various AppleTalk protocols and services. Table 3-9 provides short descriptions for some of the fields included in this command's output. Example 3-10 The show appletalk traffic Command Output Test> Show Appletalk Traffic AppleTalk statistics Rcvd...

The show controllers Command

The show controllers command displays information on all of the router's controllers. However, you can specify the type of controller so that only the information on that particular controller is displayed. Depending on the router you work with, it may have BRI, CBus, E1, Ethernet, FastEthernet, FDDI, Lex, MCI, PCBus, serial, T1, T3, Token, or VG-Anylan controllers. This command displays a variety of data such as firmware versions, memory management, and error counters for each controller's...

The show interfaces ethernet n Command

The show interfaces ethernet n command allows you to examine the status of an Ethernet interface (n specifies which one) and to get some fairly in-depth information on that interface's performance. Example 3-3 shows a sample output of the show interfaces ethernet0 command. Example 3-3 The show interfaces ethernet 0 Command Output Ethernet 0 is up, Line protocol is up Hardware is Lance, address is 0010.7b2c.5b18 (bia 0010.7b2c.5b18) MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec, rely 255 255,...

The show interfaces fddi Command

The show interfaces fddi command, similarly to other show interface commands, displays information about the state of your FDDI interface(s). Understanding the output of the show interfaces fddi command requires at least a basic level of knowledge of how different devices (SAS, DAS, DAC) connect to the FDDI ring, and of the initialization sequences of the FDDI management components (PCM, CMT, CFM, RMT, ECM, and SMT). Detailed coverage of FDDI technology, FDDI Finite State Machine, and FDDI...

The show interfaces tokenring n Command

The show interfaces tokenring n command allows you to examine the status of a Token Ring interface (n specifies which one) and the state of source-route bridging, and to get some fairly in-depth information on that interface's performance. Example 3-4 shows a sample output of the show interfaces tokenring command. The Cisco Documentation CD provides the descriptions for the fields of the show interfaces tokenring n command. Table 3-2 presents some of the field descriptions (from the Cisco...

The show ipx Commands

The are a number of show commands available for IPX (see Example 6-1). These commands display information about IPX traffic, routing, access lists, and so on, which is valuable for troubleshooting purposes. The following commands are covered in this section Example 6-1 show ipx Commands A_StubR show ipx IPX interface status and configuration Netware Asynchronous Services Interface status Sequenced Packet Exchange protocol status

The show mac Command

In the output of this command you will find the total number of sent and received unicasts, multicasts, and broadcasts per port of all line card modules (see Example 8-7). The output also includes a table that reports on the following Number of frame transmissions aborted due to MTU being too large or due to excessive deferral (Dely-Exced and MTU-Exced). Number of incoming frames that were discarded because the frame did not need to be switched and the number of CAM entries discarded due to...

The show spantree Command

This command displays detailed Spanning Tree information for the VLAN specified. The other parameters that can be used to further qualify the output, as well as a sample output of this command, are shown in Example 8-14. Table 8-7 is provided as a reference for interpreting the displayed fields. Example 8-14 show spantree Command Output BBone_Switch (enable) show spantree Usage show spantree vlan active Example 8-14 show spantree Command Output (Continued) show spantree < mod_num port_num>...

The show test Command

The show test command may be entered with or without a module number specified. The purpose of this command is to display the results of the diagnostics tests. If you are interested in seeing only the results of the tests performed on a particular module, then use this command with the number of the module you are interested in. If no module number is specified, the information displayed will correspond to the general system and module 1 (see Example 8-4). Table 8-3 provides the descriptions...

Troubleshooting Catalyst 5000 Trunking VTP and ISL

Interswitch trunk links carry traffic associated with different VLANs. There are two basic requirements for a switch to accept and forward a frame from or to a trunk port. The first requirement is that the switch must recognize the VLAN that the frame is associated with. For instance, if a switch receives a frame associated with VLAN 5, but VLAN 5 has not yet been created on the switch, the switch will not process that frame. The second requirement is that both of the switches on a trunk (ISL...

Understanding Protocol Connection Troubleshooting Targets

In order for a connection between two hosts to be successfully established, all the lower layer protocols must be in working order. For example, a transport layer protocol cannot establish a connection unless the physical layer, data link layer, and network layer are configured and performing properly. You must also keep in mind that in a lot of cases the trouble experienced may not be due to a single cause. This situation is more likely in a large (multi-hop), multi-protocol, and multi-vendor...

The show port Command

This command provides you with the most comprehensive port information, including status and counters for each of the line card modules' ports. If you do specify the port you are interested in receiving information about, then the output will be limited to that particular port. Otherwise, the output will include information about each and every port of your Catalyst switch. Refer to Example 8-9 for a sample output of the show port command. Table 8-6 provides the descriptions of show port...

Cisco Connection Online CCO

CCO provides a suite of interactive web-based services that offer open access to Cisco's information, systems, resources, and personnel 24 hours a day, 7 days a week, from anywhere in the world. Figure 1-4 displays CCO's home page (www.cisco.com). The online interactive services offered by Cisco over the Internet have evolved and grown over time. Today you have access to a wealth of technical knowledge, tips, bug information, support services, and other valuable resources all from one place....

Ping Command IPX and Apple Talk

Cisco IOS makes ping available for a number of protocols including IPX and AppleTalk. Ping for IPX and AppleTalk is available in user and privileged mode. Example 4-4 shows the syntax and the sample outputs for IPX and AppleTalk user mode pings. Example 4-4 User Mode ping (IPX and AppleTalk) Router> ping ipx 1000.0000.0c02.f3b4 Type escape sequence to abort. Sending 5, 100-byte Novell Echoes to 1000.0000.0c02.f3b4, timeout is 2 seconds Success rate is 0 percent (0 5) Router> ping appletalk...

ISDN Components and Reference Points

When ISDN is the choice of wide-area connection, the customer equipment may include terminal equipment (TE) (types 1 and 2), terminal adapters (TAs), and network termination (NT) equipment (types 1 and 2). A common two-wire facility forms the local access loop for ISDN. The line termination (LT) and exchange termination (ET) equipment are located at the edge of the service provider's network (see Figure 11-1). Figure 11-1 ISDN Components and Reference Points Figure 11-1 ISDN Components and...

Show ipx route

The show ipx route command is used to display a router's IPX routing table. This table contains information about connected IPX networks, static routes, and dynamic IPX routes leaned through IPX routing protocols in use (see Example 6-4). < 1-FFFFFFFE> IPX network number default Default route Codes C - Connected primary network, c - Connected secondary network S - Static, F - Floating static, L - Local (internal), W - IPXWAN, R - RIP, E - EIGRP, N - NLSP, X - External, A - Aggregate, s -...

DDR Triggers an ISDN Call

Before discussing or investigating ISDN Q.931 and establishment of an end-to-end circuit over the B channel(s), one must ensure that the router is properly configured to trigger the ISDN call for the appropriate traffic. To get Dial on Demand Routing (DDR) to function properly, your router needs to be configured with the following information The routing table must direct the appropriate traffic to the desired BRI interface (BRI is an example of an on-demand interface) as the exit point. This...

The Importance of SPID Numbers

ISDN Service Profile Identifier (SPID) is a configuration parameter that may or may not have to be configured on your router. This merely depends on the type of switch your service provider has and the software version on that switch.What is important to know, however, is that if the router does not need to have SPID number(s) configured, then it should not have any configured. In other words, having a SPID number configured when it is not needed should not be considered as a harmless extra...

CCO Case Management Toolkit

The CCO Case Management Toolkit is a web tool for customers with appropriate service arrangements to open, query, and update cases with Cisco TAC. Figure 1-10 displays the Case Open Help Guide (accessed from the TAC home page). Figure 1-10 The Case Open Help Guide JjsjCisco Technical Assistance Center (TAC) sco. com public support help, shtml I Profile I Feedback Search Map Help How to Use the Cisco World-Wide Technical Assistance Center Servi Order Status Em-all CCO Team This document provides...

Debug ip icmp

This command displays information about Internal Control Message Protocol (ICMP) transactions and allows you to monitor the ICMP messages sent and received by your router. Each ICMP message has a source, destination, type, and code number. RFC-792 provides complete coverage of the fields in debug ip icmp output. Example 5-8 is a debug ip icmp output sample that shows a case with five echo replies received, and a case with three host unreachable messages received. Example 5-8 debug ip icmp...

ISDN Layer

ISDN Layer 2 is concerned with the communication between the TE and the ISDN switch over the D channel. The LAPD protocol is used for this purpose. LAPD delivers control and signaling information between the TE (the router, for instance) and the ISDN switch. The LAPD protocol is formally specified in ITU-T Q.920 and ITU-T Q.921. The show isdn status command can be used to discover the status of ISDN Layer 2. If ISDN Layer 2 is reported as NOT Activated, you must first find out if ISDN Layer 1...

Cisco Works for Switched Internetworks Software

CWSI Campus is a suite of network management applications that together provide remote monitoring, configuration, and management of switched internetworks. The following are included in the CWSI Campus package For a description of these components, refer to www.cisco.com univercd cc td doc at the Cisco Documentation site. CWSI can be integrated with other SNMP-based network management systems, such as SunNet Manager, HP OpenView, and IBM NetView. Protocols such as SNMP, Cisco Discovery Protocol...

The show interfaces atm Command

As you can see from the sample output of the show interfaces atm command in Example 3-7, there are some fields displayed similar to those displayed when you issue other show interface commands. For example, the first line of the output of this command displays the state of the physical ATM interface along with the state of its link integrity, as explained in Table 3-6. Example 3-7 The show interfaces atm Command Output ATM1 0 is up, line protocol is up Hardware is cxBus ATM Internet address is...

Traceroute Command IP User and Privileged

Use the traceroute command to find the path between IP devices. Trace, introduced with the release 10.0 of Cisco IOS, is currently available only for the IP protocol. The traceroute command can be executed from the user and the privileged exec modes, but from the privileged exec mode, you have the ability to use the extended trace, which is more flexible and informative. NOTE The command traceroute is commonly used in its short form, trace. With the release 12.0 of Cisco IOS, traceroute is also...

General Problem Isolation Method for Tcpip Connectivity

In this section, a sample TCP IP network (with Microsoft hosts) is presented and the general requirements for proper operation of Telnet application in that network are specified. After that, the example is turned into a troubleshooting case. You will be walked through the step-by-step tests and checks you must run to isolate the cause of problems, and Example 5-13 debug ip ospf Command Output OSPF adjacency events OSPF events OSPF flooding OSPF lsa generation OSPF packets what you need to do...

CCIE Professional Development

Kennedy Clark, CCIE Kevin Hamilton, CCIE 1-57870-094-9 AVAILABLE NOW This volume provides an in-depth analysis of Cisco LAN switching technologies, architectures, and deployments, including unique coverage of Catalyst network design essentials. Network designs and configuration examples are incorporated throughout to demonstrate the principles and enable easy translation of the material into practice in production networks. Alvaro Retana, CCIE Don Slice, CCIE and Russ White, CCIE 1-57870-097-3...

Catalyst 5000 Switch Diagnostic Tools ping and CDP

To make use of ping, the valuable IP connectivity testing tool, on a Catalyst switch, you must assign an IP address and subnet mask to the switch's system console 0 (SCO). Since SCO is assigned to VLAN number 1 by default (this is modifiable), you have to make sure that the IP address you assign to SCO is appropriate for VLAN 1. In other words, the IP address of SCO must be chosen from the address space IP subnet that corresponds to the VLAN number assigned to SCO. It is a common error to...

Apple Talk Connection Sequence

In order to troubleshoot AppleTalk connection problems, you must understand the AppleTalk connection sequence. The connection sequence often begins when an Apple Macintosh client opens the Chooser applet from Apple's pull-down menu. This action triggers the Macintosh device to send a GetZoneList request on its connected network. The Router(s) on the local segment respond using GetZoneList reply, based on their Apple Zone table and any GetZoneList filters that may be applied to their appropriate...

Show interface serial n

The output of the show interface serial n command gives you some information similar to the output of the show command for other types of interfaces. However, with this command you must also concentrate on the type of information that is particular to Frame Relay. Example 10-1 displays a sample output of this command for a Serial interface that is configured with the encapsulation frame-relay command and has three point-to-point subinterfaces. The line numbers in Example 10-1 were added for the...

Introduction

This book is one of the members of the Cisco Press family of publications that has been developed to help you prepare yourself for the Cisco Certification examinations. This book's specific target is the Support exam (formerly the Cisco Internetwork Troubleshooting CIT Exam). I am a Certified Cisco Systems Instructor, and CIT is one of the courses that I teach. I started teaching this course in the first quarter of 1999. I have passed both the old CIT 4.0 and the new Support exams, and I am...

Global Knowledge Acquires Geotrain

Ranjbar (CCNP) is an instructor and senior network architect for Global Knowledge, Cisco's largest training partner. He is a Certified Cisco Systems Instructor (CCSI) who teaches the Cisco Internetwork Troubleshooting course on a regular basis. Born in Tehran, Iran, Amir moved to Canada in 1983 and obtained his Bachelors degree in Computing and Information Science (1988) and Master of Science degree in Knowledge Based Systems (1991) from the University of Guelph (Guelph, Ontario). After...