[Starlink] Packet losses in a router

[Starlink] Packet losses in a router

[David Fernández]

Dear participants of this list,

If you had a router that in lab conditions, with Gigabit Ethernet
interfaces, that losses 1 or 2 out of a few thousands of UDP packets
of a few hundreds of bytes each one, during a test of 1 minute, at
only 50 packets/s using iperf2, I am sure that you would investigate
why, wouldn't you?

Or it is not worth it? Just live with it?

Thank you in advance for any answer!

Regards,

David

Re: [Starlink] Packet losses in a router

[Jeff Tantsura]

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Re: [Starlink] Packet losses in a router

[Gert Doering]

Hi,

On Mon, Oct 24, 2022 at 10:13:35PM +0200, David Fernández via Starlink wrote:
> Dear participants of this list,
> 
> If you had a router that in lab conditions, with Gigabit Ethernet
> interfaces, that losses 1 or 2 out of a few thousands of UDP packets
> of a few hundreds of bytes each one, during a test of 1 minute, at
> only 50 packets/s using iperf2, I am sure that you would investigate
> why, wouldn't you?

If there isn't some reasonable explanation (like GigE -> 100M stepdown
and bursty traffic overflowing buffers), there must not be loss.  Never.

When we test new circuits we do Cisco ping "sweep rate of sizes",
which pings with 38...18000 bytes, 5 times - including fragments, this
is very many packets.  The expected result is "0 packet lost".

(Arguably this test is only exercising the circuit half-duplex, so 
the notorious 100Mbit half-duplex / full-duplex mismatch is not caught,
but any sort of one-way error is)

Gert Doering
        -- NetMaster
-- 
have you enabled IPv6 on something today...?

SpaceNet AG                      Vorstand: Sebastian v. Bomhard, Michael Emmer
Joseph-Dollinger-Bogen 14        Aufsichtsratsvors.: A. Grundner-Culemann
D-80807 Muenchen                 HRB: 136055 (AG Muenchen)
Tel: +49 (0)89/32356-444         USt-IdNr.: DE813185279

Re: [Starlink] Packet losses in a router

[Ricky Mok]

Couple plausible reasons that I encountered.

e.g., the NIC on the host simply went bad.

The cable (copper) got loose. Dirt may get into the fiber optics port.

Ricky

On 10/24/2022 1:13 PM, David Fernández via Starlink wrote:
> Dear participants of this list,
>
> If you had a router that in lab conditions, with Gigabit Ethernet
> interfaces, that losses 1 or 2 out of a few thousands of UDP packets
> of a few hundreds of bytes each one, during a test of 1 minute, at
> only 50 packets/s using iperf2, I am sure that you would investigate
> why, wouldn't you?
>
> Or it is not worth it? Just live with it?
>
> Thank you in advance for any answer!
>
> Regards,
>
> David
> _______________________________________________
> Starlink mailing list
> Starlink@lists.bufferbloat.net
> https://lists.bufferbloat.net/listinfo/starlink

Re: [Starlink] Packet losses in a router

[David Lang]

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The first thing I would check is the buffer stats on the machines you are using 
to do the communication. When I'm doing UDP syslog traffic, I have far more 
issues with the endpoints dropping packets than with the network.

David Lang

On Mon, 24 Oct 2022, Ricky Mok via Starlink wrote:

> Couple plausible reasons that I encountered.
>
> e.g., the NIC on the host simply went bad.
>
> The cable (copper) got loose. Dirt may get into the fiber optics port.
>
> Ricky
>
> On 10/24/2022 1:13 PM, David Fernández via Starlink wrote:
>> Dear participants of this list,
>>
>> If you had a router that in lab conditions, with Gigabit Ethernet
>> interfaces, that losses 1 or 2 out of a few thousands of UDP packets
>> of a few hundreds of bytes each one, during a test of 1 minute, at
>> only 50 packets/s using iperf2, I am sure that you would investigate
>> why, wouldn't you?
>>
>> Or it is not worth it? Just live with it?
>>
>> Thank you in advance for any answer!
>>
>> Regards,
>>
>> David
>> _______________________________________________
>> Starlink mailing list
>> Starlink@lists.bufferbloat.net
>> https://lists.bufferbloat.net/listinfo/starlink
> _______________________________________________
> Starlink mailing list
> Starlink@lists.bufferbloat.net
> https://lists.bufferbloat.net/listinfo/starlink
>

Re: [Starlink] Packet losses in a router

[David Fernández]

Well, asking for a friend. I will let you know the outcome, if any.

I have confirmed with your answers what I was suspecting, that this is
not normal (acceptable), even though probably you can live with it.

Thanks!

2022-10-24 22:22 GMT+02:00, Jeff Tantsura <jefftant@gmail.com>:
> If this is a 1G interface, dropping 1 packet out of (50 * 60) and with load
> below 10%, something is really wrong (I assume you are not doing SW
> switching?)
>
>
>
> Cheers,
>
> Jeff
>
>
>
> From: David Fernández via Starlink
> Sent: Monday, October 24, 2022 1:13 PM
> To: starlink@lists.bufferbloat.net
> Subject: [Starlink] Packet losses in a router
>
>
>
> Dear participants of this list,
>
>
>
> If you had a router that in lab conditions, with Gigabit Ethernet
>
> interfaces, that losses 1 or 2 out of a few thousands of UDP packets
>
> of a few hundreds of bytes each one, during a test of 1 minute, at
>
> only 50 packets/s using iperf2, I am sure that you would investigate
>
> why, wouldn't you?
>
>
>
> Or it is not worth it? Just live with it?
>
>
>
> Thank you in advance for any answer!
>
>
>
> Regards,
>
>
>
> David
>
> _______________________________________________
>
> Starlink mailing list
>
> Starlink@lists.bufferbloat.net
>
> https://lists.bufferbloat.net/listinfo/starlink
>
>

Re: [Starlink] Packet losses in a router

[David Fernández]

It is a refurbished Cisco 4000 ISR.

Yes, it does not make sense at all.

2022-11-05 13:05 GMT+01:00, Gert Doering <gert@space.net>:
> Hi,
>
> On Fri, Nov 04, 2022 at 01:54:26PM +0100, David Fernández via Starlink
> wrote:
>> FYI: The issue with packet losses was solved after the router was
>> properly synchronized using NTP, reaching up to 100 pps during 60 s
>> without losses and latency < 20 ms.
>
> This makes even less sense than before...  NTP is purely control-plane
> and should never affect forwarding.  What sort of device is this?
>
> Also, 100pps on a GigE link is close to "empty link" - a full GE link
> with 1500 byte packets comes up to ~80000 pps...
>
> Gert Doering
>         -- NetMaster
> --
> have you enabled IPv6 on something today...?
>
> SpaceNet AG                      Vorstand: Sebastian v. Bomhard, Michael
> Emmer
> Joseph-Dollinger-Bogen 14        Aufsichtsratsvors.: A. Grundner-Culemann
> D-80807 Muenchen                 HRB: 136055 (AG Muenchen)
> Tel: +49 (0)89/32356-444         USt-IdNr.: DE813185279
>

Re: [Starlink] Packet losses in a router

[Gert Doering]

Hi,

On Fri, Nov 04, 2022 at 01:54:26PM +0100, David Fernández via Starlink wrote:
> FYI: The issue with packet losses was solved after the router was
> properly synchronized using NTP, reaching up to 100 pps during 60 s
> without losses and latency < 20 ms.

This makes even less sense than before...  NTP is purely control-plane
and should never affect forwarding.  What sort of device is this?

Also, 100pps on a GigE link is close to "empty link" - a full GE link
with 1500 byte packets comes up to ~80000 pps...

Gert Doering
        -- NetMaster
-- 
have you enabled IPv6 on something today...?

SpaceNet AG                      Vorstand: Sebastian v. Bomhard, Michael Emmer
Joseph-Dollinger-Bogen 14        Aufsichtsratsvors.: A. Grundner-Culemann
D-80807 Muenchen                 HRB: 136055 (AG Muenchen)
Tel: +49 (0)89/32356-444         USt-IdNr.: DE813185279

Re: [Starlink] Packet losses in a router

[David Fernández]

FYI: The issue with packet losses was solved after the router was
properly synchronized using NTP, reaching up to 100 pps during 60 s
without losses and latency < 20 ms.

> Date: Tue, 25 Oct 2022 11:30:31 +0200
> From: David Fernández <davidfdzp@gmail.com>
> To: "starlink@lists.bufferbloat.net" <starlink@lists.bufferbloat.net>
> Subject: Re: [Starlink] Packet losses in a router
> Message-ID:
> 	<CAC=tZ0p9Eo3Gsn-C1nEYuMwoSq7n=8uCHWmx2W5NdsTwb6aC0Q@mail.gmail.com>
> Content-Type: text/plain; charset="UTF-8"
>
> Well, asking for a friend. I will let you know the outcome, if any.
>
> I have confirmed with your answers what I was suspecting, that this is
> not normal (acceptable), even though probably you can live with it.
>
> Thanks!
>
> 2022-10-24 22:22 GMT+02:00, Jeff Tantsura <jefftant@gmail.com>:
>> If this is a 1G interface, dropping 1 packet out of (50 * 60) and with
>> load
>> below 10%, something is really wrong (I assume you are not doing SW
>> switching?)
>>
>>
>>
>> Cheers,
>>
>> Jeff
>>
>>
>>
>> From: David Fernández via Starlink
>> Sent: Monday, October 24, 2022 1:13 PM
>> To: starlink@lists.bufferbloat.net
>> Subject: [Starlink] Packet losses in a router
>>
>>
>>
>> Dear participants of this list,
>>
>>
>>
>> If you had a router that in lab conditions, with Gigabit Ethernet
>>
>> interfaces, that losses 1 or 2 out of a few thousands of UDP packets
>>
>> of a few hundreds of bytes each one, during a test of 1 minute, at
>>
>> only 50 packets/s using iperf2, I am sure that you would investigate
>>
>> why, wouldn't you?
>>
>>
>>
>> Or it is not worth it? Just live with it?
>>
>>
>>
>> Thank you in advance for any answer!
>>
>>
>>
>> Regards,
>>
>>
>>
>> David
>>
>> _______________________________________________
>>
>> Starlink mailing list
>>
>> Starlink@lists.bufferbloat.net
>>
>> https://lists.bufferbloat.net/listinfo/starlink
>>
>>
>
>
> ------------------------------