[OpenWrt-Devel] [LEDE-DEV] latency on PPPoA ADSL Annex A on using Lantiq

Thu Aug 4 15:28:34 EDT 2016

Hi Rich,

There is no traffic occurring when the latency is happening.

Also icmp requests do not have any latency and are consistently returning with minimal latency.

It's only occurring in apps such as a ssh server. So whilst I was pinging and getting good results, I ssh'd into the router and it was really sluggish, eg to scroll down a 200 line file in vi is a nightmare.

So I guess this isn't bufferbloat?

Thanks

Daniel

-----Original Message-----
From: Rich Brown [mailto:richb.hanover at gmail.com] 
Sent: 04 August 2016 20:20
To: Daniel Niasoff <daniel at redactus.co.uk>
Cc: Donald Chisholm <donald.chisholm at gmail.com>; lede-dev at lists.infradead.org; openwrt-devel at lists.openwrt.org
Subject: Re: [LEDE-DEV] [OpenWrt-Devel] latency on PPPoA ADSL Annex A on using Lantiq

Hi Daniel,

(I feel like a one-trick pony here, but...) Could this be bufferbloat? Maybe not, but here's how to test:

Use the procedure for "A Quick Test for Bufferbloat" at https://www.bufferbloat.net/projects/cerowrt/wiki/Tests_for_Bufferbloat/#a-quick-test-for-bufferbloat Watch to see if the ping times increase during download/uploads then drop back down.

If the ping times do increase, consider installing luci-app-sqm as suggested on https://www.bufferbloat.net/projects/cerowrt/wiki/What_to_do_about_Bufferbloat/

Best regards,

Rich

> On Aug 4, 2016, at 3:10 PM, Daniel Niasoff <daniel at redactus.co.uk> wrote:
> 
> Hi Donald,
> 
> Thanks for responding
> 
> The MTU seems fine.
> 
> This is the WAN link
> 
> pppoa-wan Link encap:Point-to-Point Protocol
>          inet addr:2.25.173.155  P-t-P:172.16.11.136  Mask:255.255.255.255
>          UP POINTOPOINT RUNNING NOARP MULTICAST  MTU:1492  Metric:1
>          RX packets:94409 errors:0 dropped:0 overruns:0 frame:0
>          TX packets:85742 errors:0 dropped:0 overruns:0 carrier:0
>          collisions:0 txqueuelen:3
>          RX bytes:75750172 (72.2 MiB)  TX bytes:14369708 (13.7 MiB)
> 
> I sent a 1492 byte icmp request externally which got through.
> 
> root at ubuntu:~# ping -s 1464 2.25.173.155 PING 2.25.173.155 
> (2.25.173.155) 1464(1492) bytes of data.
> 1472 bytes from 2.25.173.155: icmp_seq=1 ttl=57 time=49.4 ms ^C
> --- 2.25.173.155 ping statistics ---
> 1 packets transmitted, 1 received, 0% packet loss, time 0ms rtt 
> min/avg/max/mdev = 49.439/49.439/49.439/0.000 ms
> 
> So MTU looks fine.
> 
> Thanks
> 
> Daniel
> 
> From: Donald Chisholm [mailto:donald.chisholm at gmail.com]
> Sent: 04 August 2016 19:41
> To: Daniel Niasoff <daniel at redactus.co.uk>
> Subject: Re: [OpenWrt-Devel] latency on PPPoA ADSL Annex A on using 
> Lantiq
> 
> Hi Daniel,
> 
> I just saw your message on the LEDE mailing list.  The freezing and catching up sounds like a MTU problem.  Could there be a MTU mismatch on the ADSL interface (1500 <->1492)?
> 
> Donald
> 
> On Thu, Aug 4, 2016 at 6:47 AM, Daniel Niasoff <mailto:daniel at redactus.co.uk> wrote:
> Hi,
> 
> I am quite desperate because I have a project going with these routers and I am running really late.
> 
> Can anyone spare some time to help me, I am willing to pay an hourly rate for the time if it will help.
> 
> This issue only occurs on ADSL. On VDSL performance is really good even using PPPoE.
> 
> The issue is a sluggish access to the CPU interface via ADSL, so for example if you are typing in a SSH client, it will keep freezing for a second or two, than catch up.
> 
> Routed traffic is fine.
> 
> Thanks
> 
> Daniel
> 
> -----Original Message-----
> From: Martin Blumenstingl 
> [mailto:mailto:martin.blumenstingl at googlemail.com]
> Sent: 03 August 2016 08:03
> To: Alexander Couzens <mailto:lynxis at fe80.eu>
> Cc: Daniel Niasoff <mailto:daniel at redactus.co.uk>; 
> mailto:openwrt-devel at lists.openwrt.org; 
> mailto:lede-dev at lists.infradead.org; mailto:hauke at hauke-m.de; 
> mailto:john at phrozen.org
> Subject: Re: [OpenWrt-Devel] latency on PPPoA ADSL Annex A on using 
> Lantiq
> 
> On Tue, Aug 2, 2016 at 6:10 PM, Alexander Couzens <mailto:lynxis at fe80.eu> wrote:
>> On Tue, 2 Aug 2016 13:38:55 +0000
>> Daniel Niasoff <mailto:daniel at redactus.co.uk> wrote:
>> 
>>> I can provide remote ssh access if required. When using SSH you will 
>>> notice it feels sluggish due to this issue.
>>> 
>>> Any ideas pleeeease, I am really stuck here?
>> 
>> I can confirm your problem with PPPoE on ADSL. Also noticed high 
>> latency on ssh connection through the router.
>> I guess it's not in the DSL part, because when using the TD8970 as 
>> modem with pass through everything is fine.
> someone else did performance/throughput testing on the HH5A, the 
> results are posted here: [0]
> 
> I did not have time to look into this yet, but maybe Hauke or John have an idea what's going on.
> 
> 
> [0] http://openwrt.ebilan.co.uk/viewtopic.php?f=7&p=1189
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