Fix packet loss = fix speed problems

[Headend]

Out of frustration at the speed problems I ran a simple test. Start a "single thread" download from tucows.is.co.za and at the same time ping www.sentech.co.za. What did I see...

My speed slowly builds up towards 6 kB/s. However, every now and then I get a timeout on my pings. At exactly the same time my download speed jumps down and then starts building up again.

Now if only we could find out what "they" did to start causing the packet loss then we could tell them how to fix the problem!

Headend
Tower: Mintek (82 was 12) - Signal: 19% - Firmware: 4.2.1.8 - 128k - Smoothwall and PPPoE

 

[Robone]

I agree with you. Having been running at 13% signal strength, SNL of 4 and a ber of 42% and getting lots of packet loss. Yesterday had a dish antenna installed by a subcontractor of "nowire" and now signal strength is up to 32%, SNL of 15 and ber 71%. Packet loss is a lot less than previously and now ping times are in the 200 versus in the 500 previously.

Oh you want to know speeds must admit they have improved, but I am not sure if it was sentech messing around on Sunday night or the antenna. Probably a combination of both.

Actually if anyone wants a good subcontractor to sort out your signal, in Gauteng, this is the man.

 

[Robone]

Interesting thing. I started with the modem antenna then went to a patch then an imported cantenna and now a dish. Do yourself a favour and spend the money, go for the dish. The final solution cost me R800 more because of my messing around.

 

[TheRoDent]

I have written a lengthy post before, on why packetloss affects Sentech performance. The moment TCP sees packetloss, it believes that the network is congested. Network congestion causes TCP to stop all transmission effectively, and then slowly start ramping up again with the speed. This is everyone's traffic graphs show these valleys and peaks.

Hopefully the much vaunted new "bandwidth management" tool that Sentech are about to implement doesn't control bandwidth by throwing away packets once it goes above the configured peak per package, and rather buffers the data.




<center><h6> MyWireless <s>Hacks</s> Tweaks & Tech Info || Have you checked the fawking FAQ? <br /> <font color="red">Tired of Sentech's bad service? Want to compare speeds? We at least listen...</font id="red"></h6></center>

 

[chuckl]

Ah yes, Rodent the dreaded bandwidth management by letting the packets drip onto the floor. Shades of ATM in its' initial implementations? Have to vacuum clean the towers once a week.

 

[bHOLDher]

While looking at TCP/IP tuning, I noticed this tool on win2k:
PATHPING. It tries to point out problems in routes showing % packet loss along the way. When I pathping www.is.co.za at home, I get like 5% loss to the tower, because of my -4 SNL, but at work I get 0% packet loss to the tower, but:
Hop Time Loss to Dest Loss to Router Address
2 439ms 0/ 100 = 0% 0/ 100 = 0% 66.18.65.105
13/ 100 = 13% | &lt;Link between routers
3 361ms 13/ 100 = 13% 0/ 100 = 0% gige-0-0-102.rtr-core5-stp.infosat
.net [66.18.65.106]
5-13% loss on the link between these two ?Sentech routers.

Speed is actually purdy good here today on Menlo tower with 7-8KBps with a single download. But I used to get 16KBps on this same single download.

Is this just because of packet loss of users to their towers, creating a flooded network of retransmissions and cut down Receive windows asking for acknowledgements on every 3rd packet? Or is there a problem om this link at Sentech that they do not know of? Or is this the link that is throttling our bandwidth?

Anybody have any other ideas?

 

[arf9999]

"5-13% loss on the link between these two ?Sentech routers"

Is this their back haul from the tower?



MW128, Tower <b>60</b>(Northpark Plaza), Signal:16%,S-N-L: 7, BER: 45%

 

[TheRoDent]

The packet loss is pervasive, everywhere regardless of signal strength. During our wardrive tests we saw packet loss with 52% signal and being at a distance of 40m from the damn tower.

The packet loss has got very little do with signal strength. The loss is either due to their Microwave backhauls, or due to IPWireless' crappy signalling technology.


<center><h6> MyWireless <s>Hacks</s> Tweaks & Tech Info || Have you checked the fawking FAQ? <br /> <font color="red">Tired of Sentech's bad service? Want to compare speeds? We at least listen...</font id="red"></h6></center>

 

[bHOLDher]

I wish I knew whats going on on their network, all I know is this (TRACERT):
1 250 ms 234 ms 1547 ms 66.18.87.50
2 234 ms 266 ms 219 ms 66.18.65.105
3 281 ms 250 ms 375 ms gige-0-0-102.rtr-core5-stp.infosat.net [66.18.65
.106]
4 250 ms 485 ms 500 ms gige-0-0-6.rtr-core4-stp.infosat.net [66.18.67.2
54]
5 1813 ms * 1469 ms gige-0-0-21.rtr-bdr1-rbn.infosat.net [66.18.65.2
09]

&lt;start speculating:&gt;

So, the way I understand (I am probably horribly wrong), is:
Hop 1: ..87.50 must be the tower, then
2: ..65.105 must be the router after the ?satellite? link to Sentech, then we've got the troublesome link to
3: ..65.106

Somebody please help me with the details.

 

[arf9999]

Maybe this will help (hey, I'm an optimist!):

"MyWireless hardware upgrade: 8 August 2004 05:00 - 06:00

An upgrade of one of the core MyWireless Network routers is scheduled for Sunday 8 August 05:00 - 06:00. The entire MyWireless service will be inaccessable during this period."

MW128, Tower <b>60</b>(Northpark Plaza), Signal:16%,S-N-L: 7, BER: 45%

 

[regardtv]

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by arf9999</i>

...The entire MyWireless service will be inaccessable during this period."

<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

at least this time they announce it ;-) ... normally we have to phone Orc Central to TELL them there's something wrong .... and NO I DONT have to reset my modem ....

 

[lewstherin]

I've been in direct contact with some IPWireless ppl of late.
They have confirmed a few things:
IPWireless is in the country, and are sending more personnel over the next few weeks.
They will be reconfiguring large portions of the Sentech network, including backhauls, routing and tower software and hardware upgrades.
They have promised me that the network will show significant improvement after the next 3 weeks or so.

These IPW guys I'm dealing with have been very helpful and have also have shown me really excellent customer service - especially considering I'm not even a direct customer of theirs.
They are very concerned about how Sentech has been buggering up the network - and essentially it would seem IPW has taken ownership of sorting out the network for Sentech, from what I gather. These IPW ppl seem very competent, so hoefully they'll show Sentech the way forward.

Anyhow, time will tell right?

<font color="blue">Telkom needs a leash, ICASA needs some guts, and the </font id="blue"><font color="red">SA consumer</font id="red"><font color="blue"> needs to make it happen</font id="blue">

 

[Headend]

Now I wonder why they are upgrading their core routers if the cause of speed / network problems was becuase of us 6% of users abusing their network - isn't this what or mates Marcel and Winston told everyone?

Headend
Tower: Mintek (82 was 12) - Signal: 19% - Firmware: 4.2.1.8 - 128k - Smoothwall and PPPoE

 

[qdada]

"The tail wags the dog"

 

[Razer0]

Good day fellows.
Would just like to show a ping graph at ' http://img21.exs.cx/img21/2395/gary.jpg '. This is to a battlefield1942 game server i believe is situated in joburg. So the top one is my ave everyday graph (note those frikkin RED LINES=TIMEOUT.. and it gets worse *sighs) and the bottom is strangely from yesterday early in the morning after being disconnected for +-15min from my 256k MW package. Pings are ave 140 for top one and 110 for bottom, and im 0.5km from tower in durban north... But ALAS ffs, it is back to looking like the top graph.
Can anyone explain this phenomenon??

Reality is boring for those who dont know ANYTHING about it.

 

[Perdition]

Indeed... when a tower goes down it kicks everyone off. When it's back up and people start logging on, pings will get progressively worse as more people log on. This is the inherent nature of the protocol that Sentech uses. Sentech sucks for gaming and it is unlikely to get much better even after all the "network upgrades".

 

[Razer0]

That must be the saddest reply ive heard.. ever
But i suppose i asked for it so Thanks i guess

Reality is boring for those who dont know ANYTHING about it.

 

[Robone]

These are the best ping times I have ever had pinging sentech. It used to be in the 400's then last week in the 200's. Now this:

Reply from 66.18.65.115 : bytes=32 : time=190 ms
Reply from 66.18.65.115 : bytes=32 : time=91 ms
Reply from 66.18.65.115 : bytes=32 : time=90 ms
Reply from 66.18.65.115 : bytes=32 : time=190 ms
Min=90 : Max=190 : Ave=140 ms : Packetloss = 0%

Oops , its sunday and everyone is at church

 

[Kai]

Reply from 66.18.65.115: bytes=32 time=299ms TTL=250
Reply from 66.18.65.115: bytes=32 time=587ms TTL=250
Reply from 66.18.65.115: bytes=32 time=322ms TTL=250
Reply from 66.18.65.115: bytes=32 time=481ms TTL=250

Minimum = 299ms, Maximum = 587ms, Average = 422ms

wish I could say the same

<hr noshade size="1"><font size="1"><i><div align="right"><font color="red">i haven't lost my mind, it's backed up on disk somewhere...</font id="red">
tower82.randparkridge.jhb|13-21% signal|256k package, running at 0.3 - 3k/s </div id="right"></i></font id="size1">

 

[donn]

Last week I tried pinging www.sentech.co.za from work (dedicated 128k line to Datapro) and got 6-9% packet loss, so their network was really broken, even from the outside.

This Morning (4am, Monday) the packet loss had gone down to 1-3%, and i finally managed to watch an entire BBC TV news broadcast at 32k without losing too many frames. Perhaps its improving, or could it just be than because there are no "corporate" users at that time of the morning that things are a bit better?

I see Sentech is trying to punt the service to business users, so who knows how bad the bandwidth will get?

BTW, I had to laugh: on the N1 near Rivonia there is a billboard reading "MyWireless is astounding!" (or words to that effect). If only their new customers knew just how true this is, but not in the intended sense []. That's going to haunt their service desk for years, a bit like "Makes you think, doesn't it?" did to the beleagured staff at Nedbank.

10.30am: The ink isn't even dry on my post, and the old packet loss problem is back with a vengeance:
Ping statistics for 66.18.65.115: (www.sentech.co.za)
Packets: Sent = 100, Received = 92, Lost = 8 (8% loss),
Approximate round trip times in milli-seconds:
Minimum = 69ms, Maximum = 582ms, Average = 104ms

Has anyone considered the possibility that during daylight hours the service may go loopy because their antennae overheat in the sun? Just a thought from a B.Sc.Eng (Mechanical) who knows little about radio.

Donn Edwards
http://privacy.4mg.com

http://privacy.4mg.com/SlowWireless.gif