nanog mailing list archives

Re: QUIC traffic throttled on AT&T residential


From: Ca By <cb.list6 () gmail com>
Date: Tue, 18 Feb 2020 18:00:05 -0600

On Tue, Feb 18, 2020 at 5:44 PM Daniel Sterling <sterling.daniel () gmail com>
wrote:

I've AT&T fiber (in RTP, NC) (AS7018) and I notice UDP QUIC traffic
from google (esp. youtube) becomes very slow after a time.

This especially occurs with ipv4 connections. I'm not the only one to
notice; a web search for e.g. "Extremely Poor Youtube TV Performance"
notes the issue.

I assume traffic is being throttled on AT&T's side. And it's not done
with their CPE; I'm bypassing their NAT box and connecting my laptop
directly to the ONT.

A quick google search shows people are aware that QUIC can look like
DoS traffic -- but how widely known is this problem? It may become
worse if / when sites transition to HTTP/3

For now I reject UDP 443 on the client firewall. Applications using
QUIC client libraries then fallback to TCP. This works well and I have
no issues with latency or throughput when using TCP.

May I naively ask if Google staff are working with AT&T to address this?


Sounds like you found the answer, ATT just needs to scale up your rejection
approach that is proven to work well.

Yes, most ddos traffic is ipv4 udp and yes Google was made aware that they
would be mixing with bad company in the pool of ipv4 udp traffic ... but
they have reasons.

I am not a fan of quic or any udp traffic. My suggestion was that Google
use an new L4 instead of UDP, but that was too hard for the Googlers.

So here we are.

Just say no to udp.




-- Dan


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