During a test of a VNF using host-only networking, high packet loss can be observed in the TX queue of the instance's tap interface. The test setup sends packets from one VM on a node to another VM on the same node. The packet loss appears in bursts.
The following shows a high number of dropped packets in the tap's TX queue.
ip -s -s link ls dev tapc18eb09e-01 69: tapc18eb09e-01: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master qbrc18eb09e-01 state UNKNOWN mode DEFAULT qlen 1000 link/ether fe:16:3e:a5:17:c0 brd ff:ff:ff:ff:ff:ff RX: bytes packets errors dropped overrun mcast 5500034259301 132047795 0 0 0 0 RX errors: length crc frame fifo missed 0 0 0 0 0 TX: bytes packets errors dropped carrier collsns 5481296464 81741449 0 11155280 0 0 TX errors: aborted fifo window heartbeat transns 0 0 0 0 0
Note: the queue length is shown above as
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