Tag :: CPU

This feature serves as a valuable tool for pinpointing the nature of network traffic at a device under congestion. By mirroring packets from congested queues to a designated mirror destination or CPU for analysis and monitoring, it provides network administrators and operators with the capability to gain an understanding of the traffic contributing to the congestion.

Arista switches provide several mirroring features. Filtered mirroring to CPU adds a special destination to the mirroring features that allows the mirrored traffic to be sent to the switch supervisor. The traffic can then be monitored and analyzed locally without the need of a remote port analyzer. Use case of this feature is for debugging and troubleshooting purposes.

For packets received on the front-panel interfaces and delivered to the CPU interface, this feature allows creation of a profile to configure buffer reservations for the egress CPU queues in the MMU (MMU = Memory Management Unit which manages how the on-chip packet buffers are organized).

By default, when an SVI is configured on a VXLAN VLAN, then broadcast, unknown unicast, and unknown multicast (BUM) traffic received from the tunnel are punted to CPU. However, sending unknown unicast and unknown multicast traffic to CPU is unnecessary and could have negative side effects. Specifically, these packets take the L2Broadcast CoPP queue to the CPU. 

 The "forwarding action trap" feature allows you to divert all incoming network traffic for an interface directly to the switch’s CPU for inspection and analysis. This feature is useful for advanced network testing, gaining deeper visibility into specific traffic flows, and potentially emulating existing network behaviors. Be aware that directing a high volume of network traffic to the CPU via this feature can overwhelm it.