Neotel Excessive Packet Loss VS Bandwidth Usage ?

[Jdawson]

Hi All

Declaration: This commentary which I am posting below is subject to my personal experiences. information and knowledge available to me based on my diagnosis of my Neotel Datafex Connection. I would also like to invite commentary on my understanding of the below technical analysis...!

I have been a new Neotel client for about 3 months and have been experiencing very poor performance on my Data Flex Product. Speeds maxing out at 0.8 Mbps and sustained downloading performance ranging from 0.05 Mbps to 0.2Mbs. There have been occasions when I have seen initial speeds start at 2.5 Mbps but that lasts for about 5 seconds and is very very rare. Because of this I logged complaints with Neotel and installed network monitoring and recording tools.

However the speeds which I am reviving, though not to trivialise them, are not my major concern. It’s the recent experience I have had with being billed for usage far exceeding the real use of my service which is based on a 5Gig account. I revived a bill in my second month for 11Gigs of usage then this month 42Gigs. Now I know I have not used anywhere near these figures and yet Neotel has billed me for this usage. Now I am going to be polite hear and assume they have actually got usage reports (I have not seen it yet) which indicate I have used this amount of bandwidth.

So my question is how and why?

1) I have been hacked! ...Honestly I don't think this happened unless some supper villain is hacking radio signals in the North Suburb's...of Cape Town. IF YOU READING THIS PLEASE SAY HI !:twisted:

2) Network Conditions based on my “Limited Knowledge” of Packet losses and retransmission's which I feel compelled to discuss here as this is my number ONE suspect!

These are conditions which were recorded randomly on my Neotel DataFlex connection when nothing from my side was using the connection except the network monitor and Skype. I did not run the monitoring 24/7 as I actually have work to do in my PC.

Link1
Link2
Link3
Link4
Link5

above are different intervals in the last 3 months. However this actually happens on a weekly basis I just can’t upload more than 5 files on image shack at once!

Packet loss
As alluded to above, data transfer between me and another internet computer is mostly done using TCP. TCP is a protocol designed around the assumption that some packets may not get through. For the sake of example, let us imagine I am downloading data from ati.com, and one of those many packets streaming down to me disappears en-route. Maybe a random buffer overload knocks out a router for a microsecond, and the packet is dropped. TCP notices the missing packet in the stream of sequence numbers, and so does not acknowledge its reception. The sender notices the lack of acknowledgement, and must retransmit the lost data.

This retransmission procedure adds to the amount of data flowing over the connection, and may also be lost, the receiver if it does not get the missing data quickly enough can start to fill up its buffers waiting for the old data to appear, and these full buffers will signal the transmitter to slow down. TCP has many and sometimes conflicting designs to cope with different kinds of link performances, but in the end, consistent packet loss somewhere en-route devastates TCP throughput from its theoretical maximum, even though it may be one packet in 10 or 20 that is being dropped.

So why do I care about packet loss? Well if there is continuous packet loss between me, and the server(site) I am downloading from, it doesn't matter what I do, my TCP based data (web pages or file transfers) are going to slow down and be retransmitted. In the case of my connection where I have varying degrees of packet loss for extended period of time (and these are the times that I was a where of) ranging from 25% to 90%. What does this mean in relation to the bandwidth issue I now face (which I doubt I am the only one facing)?

So this is an estimate based on me downloading a 100mb ATI file that just took 15mins during one of these sessions (See links above).

Remember these conditions are persistent over the period the download is taking place!

1) At 25% Packet loss – retransmission = 125mb's...Actual recorded Usage.
2) At 50% Packet loss – retransmission = 150mbs...Actual recorded Usage.
3) At 90% Packet loss – retransmission = 190mbs ...Actual recorded Usage.

and we not factoring in compouding loss's...?

So if this is the case? Who else could be being billed (bandwidth over-usage) for network issues which are not end-user related!

If you have a better understanding regarding this assessment please enlighten me!

 

[Jdawson]

bump ..for any feedback..?

 

[BertusK]

Same problem suspected with our telkom adsl line through Afrihost

Hi

We recently moved from iburst to a Telkom ADSL line with bandwidth supplied by Afrihost. Our usage has suddenly nearly quadrupled. The line is faster but it crashes and stops mid download. Afrihost confirmed that our line will be faster, but will peak and crash more than iburst. I only just today looked up the packet loss issue and found your post from two years back here. Your Neotel problem seem identical to my Telkom/Afrihost issue. You clearly have a lot more technical know how on the issue than I do. I did a tracert test through my MAC Utilities. Below you will see the command and then the result. Every asterisk represents a failed data packet. I think this paints the picture as clear(but less pretty) as your Graphs on Imageshack.(What utility/application did you use to track and create those useful graphs?)
We are now seriously considering going back to iburst as we never had these ridiculous data rates. Even though the download speed is not exactly as fast as the adsl line it is a lot more stable and we only paid for what we used. Not for the line's bad quality. Unless I suppose the fault lies within our hardware/line here at home. Is that a possibility? Do you still have the packet loss problem with Neotel?[/B][/B](if you're still with them)

Tracert report:


Macintosh:~ bertus$ traceroute afrihost.co.za
traceroute to afrihost.co.za (196.38.88.139), 64 hops max, 52 byte packets
1 10.0.0.1 (10.0.0.1) 39.157 ms 0.811 ms 0.728 ms
2 192.168.1.254 (192.168.1.254) 1.724 ms 1.736 ms 1.458 ms
3 196-210-140-1.dynamic.isadsl.co.za (196.210.140.1) 7.320 ms 6.492 ms 6.191 ms
4 196.38.73.113 (196.38.73.113) 8.477 ms 8.855 ms 8.213 ms
5 cdsl2-rba-vl150.ip.isnet.net (196.38.73.9) 8.778 ms 8.609 ms 8.254 ms
6 196.26.0.61 (196.26.0.61) 8.451 ms 8.792 ms 8.472 ms
7 168.209.100.242 (168.209.100.242) 9.433 ms 9.047 ms 9.220 ms
8 csw1-b-jup-bry-gi3-1.ip.isnet.net (168.209.217.21) 8.959 ms 9.283 ms 8.971 ms
9 196.34.134.105 (196.34.134.105) 8.949 ms 8.831 ms 8.950 ms
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Macintosh:~ bertus$