Exploring the Intelligent Scrollbar

In addition to seeing indications of problems within a capture, you can also easily spot issues using the Intelligent Scrollbar. To see an example of an active Intelligent Scrollbar, go to http://tcpreplay.appneta.com/wiki/captures.html#bigflows-pcap. Once there, download bigFlows.pcap and open it in Wireshark so that you can follow along. Open the capture and then go to frame 586 by doing the following:

1. Select the go to specified packet icon.
2. In the form box, type 586, then select Go to packet.
3. The Intelligent Scrollbar will display indications of network congestion within the packet list, as shown in the following screenshot:

Figure 17.8 – Visualizing network congestion

The Info column header on the right-hand side lists several indications of trouble that warrant further investigation. These include the following:

• [TCP Out-Of-Order]
• [TCP Retransmission]
• [TCP Dup ACK 587#1]
...