Chapter 4 Capturing and Decoding Packet Data

Files

Note Capture files on the NAM 2200 Series appliances are stored in native NAM format. You can convert the capture file format to .pcap using the Convert/Rename/Merge button on the Capture > Packet Capture/Decode > Files window.

Analyzing Capture Files

The Capture Files window (Capture > Packet Capture/Decode > Files) enables you to obtain various statistics including traffic rate (bytes/second) over a capture period, lists of hosts, conversations, and applications associated with network traffic.

This window also enables you to drill-down for a more detailed look at a particular set of network traffic. The pane above the Traffic over Time graph displays the time shown in the graph in the From: and To: fields. It also provides fields for Protocol and Host/subnet, and a Drill-Downbutton.

Note After clicking the Drill-Downbutton, the Host Statistics results table will display both source and destination hosts, if either the source or destination host of the traffic belongs to the Host/Subnet that you had specified.

Each slice in the Traffic over Time graph displays the amount of traffic for the amount of time set in the Granularity of the capture file.

You can view more detail about a specific time frame by entering the time in the From: and To: fields and choosing Drill-Down. You can also drill-down on a specific Protocol or Host/subnet address.

Table 4-7describes the different areas of the capture analysis window.

Table 4-7 Capture Analysis Window Fields

Field

Description

 

 

Capture Overview

Provides a summary of the displayed capture including number of packets

 

captured, bytes captured, average packet size, capture start time, duration of

 

capture, and data transfer rate (both bytes and bits per second)

 

 

Traffic over Time

Displays a graphic image of network traffic (KB/second)

 

 

Protocol Statistics

Displays packets and bytes transferred for each protocol

 

 

Hosts Statistics

Displays packets and bytes transferred for each host address

 

 

Error Scan

Note This feature is available for .pcap files, but not for .capture files.

The Capture Errors and Warnings Information screen shows warnings and errors, and packet irregularities. From this screen, you can launch the Packet Decode Window, where you can drill-down to packet details (select a row in the table and click the Decode Packet button).

To get to the Capture Errors and Warnings Information screen, choose Capture > Packet

Capture/Decode > Files. Highlight a file and click the Errors scan button.

 

 

User Guide for the Cisco Network Analysis Module (NAM) Traffic Analyzer, 5.0

 

 

 

 

 

 

OL-22617-01

 

 

4-17

 

 

 

 

 

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Cisco Systems NAM, 5 manual Analyzing Capture Files, Error Scan, Displays a graphic image of network traffic KB/second