Re:  Re: Physical distance performance with Linux?

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Re:  Re: Physical distance performance with Linux?

Christoph Kuhr
Does it matter whether it's only the cable side or the transition from ethernet to cable?
Both processes are out of the users control...
But I can confirm ~35ms on the first hop with my cable access...

Where did you find that info?

Bet,
Ck
Am 15.05.20, 22:58 schrieb Chris Caudle <[hidden email]>:
On Tue, May 5, 2020 2:43 pm, Christoph Kuhr wrote:
> Well, actually using the same ISP in the same city does not
> make a difference. My mate and me have both
> Unitymedia/Vodafone cable network access. We had the same RTT
> as with the other one at another ISP with ADSL.

I have been looking for information on the latency associated with the
cable modem. So far this is the only information I found, but it is not
clear whether this refers just to the latency on the cable side, or also
includes the latency of converting from the Ethernet side to the cable
side:

"The average DOCSIS upstream latency for best effort traffic has been
measured to be 11-15 ms with the potential of a significantly higher
maximum latency up to 50 ms under medium to heavy channel utilization."

So already a significant latency, and potentially high latency variation,
before even getting to the first router.

It is impressive that you have found a way to play live together with that
connection.

--
Chris Caudle
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Re:  Re: Physical distance performance with Linu x ?

Chris Caudle
On Tue, May 19, 2020 4:47 am, Christoph Kuhr wrote:
> Does it matter whether it's only the cable side or the
> transition from ethernet to cable?

Only to the extent of estimating whether that is the actual range of
latency to expect from your house to the upstream router, or whether there
is additional latency added on to that as a minimum.

> But I can confirm ~35ms on the first hop with my cable access...

Is that 35ms one way, or round trip?  Is that the value reported from
traceroute?  I'm looking at that now at my house, but I'm not familiar
with how to interpret the numbers, I will need to study the man page a
bit.
But if the interpretation is as obvious as it seems then it seems like the
system in our neighborhood has not bad latency after the latest upgrades.

> Where did you find that info?

Google search found a document at CableLabs titled "DOCSIS Technologies
for Mobile Backhaul" discussing considerations for using cable based
network as the connection for small cell phone stations.  Similar
considerations for conversations as for music, if the latency is too long
you begin to speak over each other, conversation timing is awkward, etc.
so seemed like a relevant document.
https://www.cablelabs.com/docsis-mobile-backhaul-white-paper
https://cdn2.hubspot.net/hubfs/1697621/DOCSIS-Technologies-For-Mobile-BackHaul-May-2018.pdf

best regards,
Chris Caudle
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