CODA-4582 - Open Issues for Investigation

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I Plan to Stick Around
Posts: 10

Re: CODA-4582 - Open Issues for Investigation

Is there another modem I can switch to? It looks like these UDP issues are now 5 months in. As it stands now I can't reliably use anything that needs UDP. 

Resident Expert
Resident Expert
Posts: 6,111

Re: CODA-4582 - Open Issues for Investigation

@DeeNice the CODA-4582 with firmware version 2.0.10.27 is the best that you're going to see from any Puma 6 (CGN3xxx) or Puma 7 modem.  

 

Just to note the download links for the iperf downloads are working now:   https://www.neowin.net/forum/topic/1234695-iperf-316-windows-build/#comment-596631033

 

I haven't tried version 3.16 just yet, but, soon.  I expect to see a drop in the UDP losses, but, I don't expect the Puma 7 modem to match a Broadcom modem in terms of UDP losses, at least, not at this time. 

 

Are you trying to run a backup to a server with UDP, or gaming which requires UDP?  Fwiw, with that combination of 4582 and V2.0.10.27, you can run sessions with League of Legends and not have any UDP packet losses.  That observation comes from looking at my son's network logs. 



I'm a Reliable Contributor
Posts: 609

Re: CODA-4582 - Open Issues for Investigation

I wish the new gateaway is a broadcom, would be a dream!

I Plan to Stick Around
Posts: 10

Re: CODA-4582 - Open Issues for Investigation

@Datalink I run a variety of things on UDP (both as a client/server) so it's a bit broad, and unfortunately affecting the service quite a bit. I don't suppose flipping this into Gateway mode and attaching a router won't solve anything eh? 

Resident Expert
Resident Expert
Posts: 6,111

Re: CODA-4582 - Open Issues for Investigation

Nope.  I run that combination and see the losses with UDP when I test with Iperf.  There was a test run in the last month or two at a customers home.  One observation that came out of that was that UDP losses were observed to be higher when the connected CMTS had upstream congestion.  So, part of the problem might be upstream congestion at the CMTS.  

 

Any chance you can flip any of those applications to TCP/IP?

 

Fwiw, the observations in the github site regarding excessive UDP losses were closed with the recent iperf updates, but, I still don't know if I trust it to see an accurate result.  There is NUTTCP as well, but, you need a cooperating server to run that:

 

https://www.nuttcp.net

 



I'm Here A Lot
Posts: 7

Re: CODA-4582 - Open Issues for Investigation

I'm not sure what to think bout this whole ordeal. Earlier I posted that with a VPN I get no packet loss but it was agreed that it's because it's not making out my bandwidth therefore not causing bufferbloat. However Ive actually done speedtests and get 100+ download on my vpn connection and I'm on 100u so it is actually indeed maxing out my bandwidth. I only see packet loss when I don't use a VPN and everything gets routed through Rogers hops. When I am on VPN I experience virtually no packet loss and get a stable 40 ms connection
I Plan to Stick Around
Posts: 10

Re: CODA-4582 - Open Issues for Investigation

The iperf issues you're referring to are only seen at 10GB or higher speeds (i believe, check the patch notes to verify).

 

I unfortunately can't flip my apps over to UDP, and more importantly shouldn't have to.

 

Seeing that this thread has 5 months of history is concerning. I'll ride it out for now, but I don't have much confidence in Rogers fixing this if they haven't been able to since January. They knew (after buying a ton) that the Puma 6 chips were trash, then they doubled down on puma 7 and only have 1 seriously flawed modem available?

Resident Expert
Resident Expert
Posts: 6,111

Re: CODA-4582 - Open Issues for Investigation

I ran Iperf UDP tests tonight with V3.16.  UDP 40 Mb/s up with no losses.  I've hit 50 Mb/s up with 3.13 and no losses, so, I'm concluding that upstream congestion and time of day has a lot to do with this.  Download is terrible, only 500k UDP without any losses.  Thats with the modem in Bridge mode with an Asus RT-68U behind it.  So, the problem with Iperf UDP losses are seen in the 4582 at low data rates.  On my list of things to do is flip the modem back into Gateway mode and run the same test.  Maybe when DOCSIS 3.1 upstream is deployed, we might see some improvement with the UDP losses. 

 

As for Rogers fixing this?  This isn't a Rogers problem.  Its an Intel problem where Intel isn't saying anything publicly as to whether or not the Puma 6 modems can really be fixed.  And it looks like some issues such as UDP have migrated to the Puma 7.  There are millions of these modems in use around the world and each MSO is having to put up with the issues that the Puma 6 chipset has generated.  These modems were first introduced by Intel around 2012, and it wasn't until last summer that Rogers Engineering staff determined that there were problems that needed to be addressed and started working thru those issues.  Compared to a good many other MSOs around the world, Rogers is way, way ahead of the curve on the problems with these modems and has been working hard, in conjunction with Intel and Hitron to address those problems.  Other MSOs are still indicating to their customers that "nope, all is good here, must by your equipment".  Nothing can be further from the truth.  At the end of the day however, its up to Intel to modify the base code that allows the manufacturers to develop the final product.  Without those modifications, these issue go no where, and that's for all MSOs world wide, not just Rogers.

 

Fwiw, if you knew the history of the latency with the Puma 6, you would also know that the Puma 7 is much improved.  For some reason Rogers decided to incorporate the Puma 7 modem into the product line instead of a Broadcom based DOCSIS 3.0 32 channel / Docsis 3.1 modem.  Don't know the reason, I can only speculate that the modem cost factors into that decision, along with manufacturer support.  Maybe there are other reasons?  One can only speculate........

 



Network Architect
Network Architect
Posts: 611

Re: CODA-4582 - Open Issues for Investigation

@DeeNice

 

In the UDP test you are running, you are pushing 1000 Mbps from a server on the Internet down to your modem and you receive 96% of the packets. This is actually a really good result.

 

The reality is that no matter what you do, the LAN interface has some overhead and it will virtually max out at about 950-960 Mbps.

 

If you retry your test lowering the bandwidth to 900 Mbps for example, I would expect you would get better results.

 

Dave

Network Architect
Network Architect
Posts: 611

Re: CODA-4582 - Open Issues for Investigation

As of yesterday, we have promoted firmware 2.0.10.27 on the CODA-4582 to production.

 

This means that everybody is eligible to receive it with a simple reboot of their modem. We will resume the trial program as soon as I receive the next firmware (2.0.10.29).

 

Dave