How to interpret External passthrough Network Load Balancer log entries.

[Janet7Code]

Hi Friends,

I'm having trouble interpreting load balancer log entries, for example, I have this log entry from an External passthrough Network Load Balancer. the jsonPayload shows 1192 bytes received  and 4 packets sent, however there's no 'bytesSent' field.

Also I heard that the incoming and outgoing traffic are sampled at different rates. Does it mean if I see big differences between incoming and outgoing packets(bytes), it does not necessarily mean the incoming and outgoing traffic look that different? The difference could also be caused by the different sample rates?

{
"insertId": "XXXXXXX",
"jsonPayload": {
"bytesReceived": "1192",
"@type": "type.googleapis.com/google.cloud.loadbalancing.type.ExternalNetworkLoadBalancerLogEntry",
"rtt": "0.036694340s",
"packetsSent": "4",
"startTime": "2024-09-22T08:29:58.98739853Z",
"endTime": "2024-09-22T08:29:59.02409287Z",
"connection": {
xxxxxxxxxx
},
"packetsReceived": "4"
},
"resource": {
XXXXXXX
}
},
"timestamp": "2024-09-22T08:29:59.024092870Z",
"logName": "projects/XXXXXXXX/logs/loadbalancing.googleapis.com%2Fflows",
"receiveTimestamp": "2024-09-22T08:30:09.001599298Z"
}