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0 pointskiitos2y ago0 comments

> Both load balancers and backend servers can juggle millions of concurrent connections nowadays.

Maybe with SO_REUSEPORT, but not in general.

A TCP connection is identified by a 5-tuple that requires a unique port for both the client and server. TCP represents ports as uint16s, which means the max number of possible ports per address is 65536.

tl;dr: 1 server IP address = no more than 64k incoming connections

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otterley2y ago

Yes, I'm aware that 4-tuples must be unique. And so, by having a LB and/or server bind to more than one IP address, you can easily overcome that limit.

kiitosOP2y ago

If you have multiple client-accessible IP addresses available to a server, I guess? But that's in no way common?

otterley2y ago

It's quite common in Kubernetes deployments, where each server in a separate Pod binds to a separate IP address.

And, as I said before, with DSR, there's a broad diversity of client IPs, so a single server address doesn't typically cause concerns with 4-tuple exhaustion.

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0 pointskiitos2y ago0 comments

> Both load balancers and backend servers can juggle millions of concurrent connections nowadays.

Maybe with SO_REUSEPORT, but not in general.

tl;dr: 1 server IP address = no more than 64k incoming connections

0 comments

otterley2y ago

Yes, I'm aware that 4-tuples must be unique. And so, by having a LB and/or server bind to more than one IP address, you can easily overcome that limit.

kiitosOP2y ago

If you have multiple client-accessible IP addresses available to a server, I guess? But that's in no way common?

otterley2y ago

It's quite common in Kubernetes deployments, where each server in a separate Pod binds to a separate IP address.

And, as I said before, with DSR, there's a broad diversity of client IPs, so a single server address doesn't typically cause concerns with 4-tuple exhaustion.

1 more reply

j / k navigate · click thread line to collapse