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

Kevin Darbyshire-Bryant kevin at darbyshire-bryant.me.uk
Fri Aug 5 14:07:29 EDT 2016


I can confirm this.  Have seen it myself on a DGN3500, reported at least
a month ago.  Router terminated traffic is slow, routed traffic to/from
internal lan is fine.  It's not bufferbloat.

On 04/08/16 16:20, Daniel Niasoff wrote:
> One more thing I forgot to mention is that router traffic is fine so if I dnat to a host on the internal lan, performance is good.
> 
> So if it was bufferbloat it would affect all hosts
> 
> -----Original Message-----
> From: openwrt-devel [mailto:openwrt-devel-bounces at lists.openwrt.org] On Behalf Of Daniel Niasoff
> Sent: 04 August 2016 20:29
> To: Rich Brown <richb.hanover at gmail.com>
> Cc: lede-dev at lists.infradead.org; openwrt-devel at lists.openwrt.org
> Subject: Re: [OpenWrt-Devel] [LEDE-DEV] latency on PPPoA ADSL Annex A on using Lantiq
> 
> 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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