Tab – TCP/IP

All TCP/IP counters are measured on a system-wide basis. They accumulate all occurrences of a specific event type on every physical network interface as well as the internal traffic (loopback, 127.0.0.1).

This graph shows the rate at which new TCP connections are created. The input/passive open rate is the rate at which the system is receiving new connections. The output/active open rate is the rate at which the system is making new connections to other systems.

This graph shows the number of open TCP connections. This includes long-living connections such as ssh as well as short-living ones like scp/https. If the number of open connections increases over time, this may indicate local or remote processes not releasing/closing connections.

This graph shows the average size of TCP packets being transferred from and to the system. This parameter may help to characterize the traffic. Sustained packet sizes near 1500 bytes show bulk file transfers whereas smaller packets show interactive or request/response traffic.

This graph shows the percentage of incoming and outgoing packets that were retransmitted. High values for either of these are an indication of either a congested network dropping packets or long delays.

Retransmission occurs when no confirmation of receipt has occurred for the original packet and the system has to resend the packet.

This graph shows the rate at which TCP ports are being reset, i.e. connections being refused.

Describes the rate at which the active TCP connections that the system is attempting fail to open.

This graph shows the rate at which new connection attempts have been dropped from the listen queue. This happens when the system is receiving new connection requests faster than it can handle them.