we are not able to go beyond certain PPS while using N2 computes. The number is constant no matter which N2 shape we use. Can you please help us to understand what’s causing the problem?
Generally we deal with UDP(RTP) traffic of packet size 32 Bytes and frame size 74 Bytes. When we use public IPs, it looks like that some kind of rate throttling is happening and we are not able egress beyond 115 Mbps.
Thee same issue is not observed with private IP traffic of same packet size.
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You are almost certainly running into either an explicit limitation for external/Public IP traffic or an inherent performance limitation for same. Per the 2018 Usenix paper for "Andromeda" that type of traffic takes a different path through the networking/hypervisor software than private IP traffic.
"usenix andromeda" as search fodder should find the paper/presentation. Of course there have likely been at least a few changes since 2018 but the general thrust of what is described therein should be broadly applicable.
I would recommend you get in touch with the official support channels and/or your account rep(s).
Google Cloud protects each VM by limiting ingress traffic delivered to an external IP address associated with the VM. The limit is 1,800,000 pps (packets per second) link.
The PPS limit * 72 bytes per packet results in 127 Mbits/sec which is close to the limit you have observed.