Observer Analyzer : Observer Analyzer : Expert Analysis : Using Connection Dynamics
Using Connection Dynamics
Connection Dynamics show a selected conversation graphically illustrating the inter-packet delays as spacing between packets.
Prerequisite: Observer Expert or Observer Suite
Packet-to-packet delay times are shown graphically, allowing instant identification of long latency and response times. Retransmissions and lost packets are flagged in red for quick identification. The packet display can contain either a brief or detailed view of each packet’s contents.
To access Connection Dynamics, right-click a conversation in either the TCP Events or the UDP Events and select Connection Dynamics. Once a conversation has been displayed in Connection Dynamics, it can be reviewed by clicking the Connection Dynamics button on the Expert button bar.
Connection Dynamics show a selected conversation graphically illustrating the inter-packet delay as a spacing between packets. Packet-to-packet delay times are shown graphically, allowing instant identification of long latency and response times. Retransmissions and lost packets are flagged in red for quick identification. The packet display can contain either a brief or detailed view of each packet’s contents. For example, if you see delays in query response time from a database server, it could mean that your server's processor is overloaded and needs to be upgraded. It could also help pinpoint problems with custom applications running on servers.
After accessing Connection Dynamics—the tool itself—the time line format lets you quickly see long latencies and delayed response times. Retransmissions and lost packets are flagged in red.
Place your mouse cursor over a packet; it will turn blue. At the bottom of the screen (above the lower tabs Expert Analysis, Decode, Summary, and others) more detailed information for that packet is shown. In general, the information has abbreviated titles:
S1
Sequence Number
A1
Acknowledgment Number
EA1
Expected Acknowledgment Number. This value is calculated by Observer and is not part of any byte within the TCP header.
W
Window Size
P
Port Number
DataLen
Data Length
Seq
Sequence Number
ExpAck
Expected Acknowledgment Number
Ack
Acknowledgment Number
Wnd
Window Size
Port
Port Number
AbsoluteTime
Absolute Time
TSN
Transmission Sequence Number
DupTSN
Duplicate TSN detected. This value is reported by the SACK packet.
GapACK
Gap in TSN sequence detected. This value is reported by the SACK packet.

1 These are used to validate that data has been received properly. The time difference between packets 9 and 10 is the length of time it took the server side (the system on the right) to respond back to the clients request (the system on the left).

Now, by right-clicking any packet you can:
jump to the Decode window display of that particular packet,
toggle the display packet Details on or off, or
change the zoom level of the Connection Dynamics window.
Press the Tools button and select Find Packet. This opens the Find dialog box so you may specify search criteria. Use this tool to help you find what you are looking for in a long sequence of packets.