Basic traffic requirements

Any loss of critical network TCP packets can prevent the DNCA from reassembling the TCP traffic into HTTP hits. Lost TCP packets can result in Discover sessions with missing pages, partial pages, or both. In a worst-case scenario, the entire session can be unusable.

Confirm the following basic requirements with your network administrator:

• Traffic stream: The DNCA requires bidirectional traffic stream or two unidirectional traffic streams containing all HTTP requests and responses traffic between your web application and the visitor browsers that are interacting with it.
• No errors or dropped packets: No errors, dropped packets, or overrun packets at operating system network interface card and network level.
  • An ifconfig ethX command on the capture NIC must display a constant number of dropped packets or errors.
  • If the number is increasing at a high rate, there can be problems with the fidelity of the traffic sent to the DNCA. There can be inadequate sizing of your DNCA hardware for your traffic volume, or both.
• Real visitor IPs: The capture point can see the real visitor IPs or host address of visitor's IP.

  Access to the real IP address of your visitors is a valuable resource for troubleshooting purposes. For customers who use load balancers, this requirement cannot be possible.

• Filtered traffic: Spanned traffic is filtered down to the essential traffic only.

  Discover recommends filtering out as much unnecessary traffic as possible at the network level before it is delivered to the DNCA. This filtering offloads processing resources that the DNCA must use to filter out traffic.

• TCP persistent connections issues:

  To capture traffic, the DNCA must see the start of all TCP connections.