[Outages-discussion] NTT - High Latency between Dallas and LA exchanges

[John Kristoff]

On Thu, 18 May 2023 13:04:20 +0000
Joseph Jackson via Outages-discussion <outages-discussion at outages.org>
wrote:

> As a voip provider whose traffic is almost all UDP and a lot of it I
> had no idea this was something that people, much less ISPs thought.
> I have never come across the idea that UDP traffic through routers at
> least in my experience was being rate limited.

I don't know how widespread it is, but this was precisely something I
had done many years ago before QUIC.  Slammer was what stimulated me to
implement "edge" rate limits on UDP traffic towards external
destinations at an edu.  So for example, ingress to the network
traffic from an end user subnet I set a max of 10 Mb/s for UDP traffic
not destined to internal prefixes.

I left the organization and came back years later. When there were
complaints of some random real-time game performance I discovered
someone had later put an aggregate limit of about 100 to 200 Mb/s for
UDP at peering routers, and with the rise of the QUIC, that limit was
now being reached by the total sum of UDP traffic from all internal
subnets. I preceded to get rid of the hard coded UDP limits with this
new reality.  It seemed like a reasonable thing to do at the time, but
not so much now.  Like manually configured bogon filters I would assume
there may be similar cases lurking out there.

John