Tag Archives: 1.3a

1.3.a Use IOS troubleshooting tools

1.3.a [iii] Embedded packet capture

The Cisco IOS Embedded Packet Capture (EPC) is a software feature consisting of infrastructure to allow for packet data to be captured at various points in the packet forwarding path. The network administrator may define the capture buffer size and type (circular, or linear ) and the maximum number of bytes of each packet to capture. The packet capture rate can be throttled using further administrative controls in order to ensure that it doesn’t overwhelm the router. For example, options allow for filtering the packets to be captured using an ACL or by specifying a maximum packet capture rate and/ or by specifying a sampling interval.

Adam, Paul (2014-07-12). All-in-One CCIE V5 Written Exam Guide (Kindle Locations 1369-1370).  . Kindle Edition.

http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/epc/configuration/15-mt/epc-15-mt-book/nm-packet-capture.html

 

 

 

1.3.a Use IOS troubleshooting tools

1.3.a Use IOS troubleshooting tools

There are two categories of troubleshooting tools that are out there. One that help you troubleshoot IOS related issues but they are web based (E.g. Cisco Output Interpreter), the others are built-in tools that are part of Cisco IOS itself and help a router or switch administrator troubleshoot a network. Example of IOS based tools are ping, traceroute, and show and debug CLIs.

Adam, Paul (2014-07-12). All-in-One CCIE V5 Written Exam Guide (Kindle Locations 1337-1340).  . Kindle Edition.

1.3.a Use IOS troubleshooting tools

1.3.a [iv] Performance monitor

Cisco performance monitor enables you to monitor the flow of packets in your network and become aware of any issues that might impact the flow before it starts to significantly impact the performance of the application in question. Performance monitoring is especially important for video traffic because high quality interactive video traffic is highly sensitive to network conditions (such as packet drops). Even minor issues that may not affect other applications can have dramatic effects on video quality.

Adam, Paul (2014-07-12). All-in-One CCIE V5 Written Exam Guide (Kindle Locations 1373-1377).  . Kindle Edition.

http://www.cisco.com/c/en/us/td/docs/ios/media_monitoring/configuration/guide/15_1m_and_t/mm_15_1m_and_t/mm_pasv_mon.html

SUMMARY STEPS

1. enable

2. configure terminal

3. flow exporter exporter-name

4. description description

5. destination {ip-address | hostname} [vrf vrf-name]

6. export-protocol netflow-v9

7. dscp dscp

8. source interface-type interface-number

9. option {exporter-stats | interface-table | sampler-table} [timeout seconds]

10. output-features

11. template data timeout seconds

12. transport udp udp-port

13. ttl seconds

14. end

1.3.a Use IOS troubleshooting tools

http://www.cisco.com/c/en/us/support/docs/ip/routing-information-protocol-rip/13730-ext-ping-trace.html

1.3.a [ii] ping, traceroute with extended options

When a normal ping command is sent from a router or a layer-3 switch, the source address of the ping is the IP address of the interface that the packet uses to exit the router. If an extended ping command is used, the source IP address can be changed to any IP address on the router. The extended ping is used to perform a more advanced check of host reachability and network connectivity. The extended ping command works only at the privileged EXEC command line.

The extended traceroute command is a variation of the traceroute command. An extended traceroute command can be used to see what path packets take in order to get to a destination. This is helpful for when you troubleshoot routing loops, or for when you determine where packets are getting lost (if a route is missing, or if packets are being blocked by an Access Control List (ACL) or firewall). You can use the extended ping command in order to determine the type of connectivity problem, and then use the extended traceroute command in order to narrow down where the problem occurs.

Adam, Paul (2014-07-12). All-in-One CCIE V5 Written Exam Guide (Kindle Locations 1358-1362).  . Kindle Edition.