Flow Log Overview

What Is a Flow Log?

Log Tank Service (LTS) can record flow logs for enterprise routers. A flow log records traffic of attachments on enterprise routers in real time. These logs allow you to monitor the network traffic of attachments and analyze network attacks, improving the O&M efficiency.

Creation Process

Before creating a flow log for an enterprise router, you need to create a log group and a log stream on the LTS console.

Figure 1 Process of creating a flow log

Notes and Constraints

• By default, you can create a maximum of 20 flow logs.
• For TCP and UDP fragments, flow logs can record only the first fragment. Other fragments cannot be recorded because of incomplete packet header.
• Flow logs can only record traffic generated for network communications and do not capture traffic generated by the network. For example, BGP traffic used by an enterprise router to learn routes of attachments is not recorded.