Triband Nu Users Beware - Part Of Your Downloads During Nu Hours May Be Charged To Your Non-nu Quota


TriBand NU users BEWARE - part of your downloads during NU hours (00:00->08:00 IST)
may be charged to your non-NU quota of 1GB/mo.

While going through the session details for May/2006, I came to the
conclusion that the time on MTNL's TriBand billing system is
approximately 9-10 mins. ahead of IST.

I can say this with assurance because I schedule the downloads on my Linux
Intranet server to begin @ 00:02 and terminate @ 07:58. This server also
provides NTP services to other nodes on my LAN; the "ntpd" daemon on this
server keeps itself synchronized with reputed public NTP servers (e.g. on the Internet.

At 23:59 and 07:59 hours this server also executes a script to reboot the ADSL
modem, thereby forcing distinct "pppoe" login sessions for NU and non-NU hours
respectively. After running the ADSL modem reboot script the server
shuts itself down at 08:00 hours. At this point of time, save the ADSL modem
all nodes are powered OFF i.e. no IP traffic on the LAN.

With such a scheduling system in place, I was certain that none of my downloads
would spill over to the non-NU hours and that the time stamps on MTNL's detailed
session reports would be in sync give or take 60 secs. at most.

However, on close examination of the "session details" I was surprised to see
downloads MBs being charged to my account and stopping at around 08:08:08 to
08:09:59 (see records marked * below). [To avoid these charges, I had to
terminate my download around 07:48 hours]

Another anamoly noted on the session details is "overlapping" pppoe
sessions! I have only one ADSL line/modem so how can overlapping pppoe
sessions be possible? (see records marked + below).

Every TELCO has access to highly accurate atomic clocks through which they can
set the time on their various equipment. Therefore IMHO MTNL, being an incumbent
TELCO, has no excuse for such big differences in their system times.

The point here is that when you publish a time for the NU hours it has to adhere to
some standard. In this case it is IST. We all understand that implicitly and
accordingly schedule our jobs to avail the service offered during that time.

In MTNL's case, this does not seem to be the case. In May it was 9-10 mins.
In future it may be worse than above. The consumer has no way of knowing the
time difference (from IST) on MTNL's billing system until **after** the fact.

Such practice on their part is plain wrong and I would venture to say they are
billing their NU Plan customers incorrectly. For May/06, a rough calculation shows 173MB,
that I thought was unmetered, was charged to my 1GB monthly quota - roughly

If you are subscribed to the NU Plan then monitor your downloads during NU hours.
Ensure that your computer's system time is reasonably accurate by synchronizing it
regularly, with a public NTP server and maintain logs of your download start
and end times. Compare your log with the "session details" from MTNL's report

Please post your own experience here to gauge the gravity of this issue.

Listed below is a pruned session detail report showing my findings.

Session History Details
Usage history of 'aaaabbbb' from 01-May-2006 to 31-May-2006
Start Date End Date Quantity Billed (MB)
+ 01/May/2006 00:05:11 01/May/2006 08:07:20 0.0191
+ 01/May/2006 08:05:34 02/May/2006 00:03:15 15.0432
+ 03/May/2006 00:04:37 03/May/2006 08:07:13 0.0257
+ 03/May/2006 08:05:42 04/May/2006 00:06:23 29.6274
+ 04/May/2006 00:04:42 04/May/2006 08:07:18 0.0103
+ 04/May/2006 08:05:48 04/May/2006 23:42:24 26.7329
+ 04/May/2006 23:40:46 04/May/2006 23:45:47 0.0171
+ 04/May/2006 23:44:00 04/May/2006 23:50:01 0.083
+ 04/May/2006 23:48:16 04/May/2006 23:56:24 0.2822
* 13/May/2006 00:05:24 13/May/2006 08:08:30 5.4775
* 14/May/2006 00:05:32 14/May/2006 08:08:08 6.0176
* 15/May/2006 00:05:37 15/May/2006 08:08:43 13.8309
* 16/May/2006 00:05:41 16/May/2006 08:08:47 13.9385
* 17/May/2006 00:05:46 17/May/2006 08:08:22 13.3174
* 18/May/2006 00:05:52 18/May/2006 08:08:28 13.1461
* 19/May/2006 00:05:54 19/May/2006 08:08:30 12.8393
* 20/May/2006 00:06:00 20/May/2006 08:08:36 13.687
* 22/May/2006 00:06:11 22/May/2006 08:08:47 10.8236
* 23/May/2006 00:06:15 23/May/2006 08:08:51 9.7693
* 26/May/2006 00:18:17 26/May/2006 08:09:21 14.5032
* 27/May/2006 00:06:37 27/May/2006 08:09:43 15.204
* 28/May/2006 00:06:41 28/May/2006 08:09:47 15.3887
* 29/May/2006 00:06:45 29/May/2006 08:09:51 15.1079
* 30/May/2006 00:03:52 30/May/2006 08:09:28 14.3707
+ 30/May/2006 08:07:59 30/May/2006 13:49:07 0.3732
+ 30/May/2006 13:47:32 30/May/2006 22:14:43 94.3865
+ 30/May/2006 22:56:59 31/May/2006 00:20:15 0.0424
*+ 31/May/2006 00:18:40 31/May/2006 08:09:43 1.2511
+ 31/May/2006 08:08:01 31/May/2006 23:40:37 18.4533
+ 31/May/2006 23:38:47 01/Jun/2006 08:09:59 0.0042 \
+ 31/May/2006 23:38:47 01/Jun/2006 08:09:59 0.002 / 2 records
for the same
pppoe session?
* Download during NU hours spills over to Non-NU hours and is billed to Non-NU
+ Overlap in time stamps of consecutive pppoe sessions.


Yes, I think its quite well known and some (like me) have even learnt about it the hard way. Imo you are cutting it rather fine anyways. Many long time users of TriB NU sync their computer clocks to MTNL by oberving the time difference. I prefer to keep a comfortable time gap of 15 minutes at either end, connect at 0015, disconnect and shutdown at 0745. I lose 30 minutes (somewhere around 40MB for me) straightway but at least I can sleep peacefully.I know it sucks. I have myself paid through the nose once, for issues like this. But after nearly 8 years online I've seen many ISPs and their quirks and I've learnt to live with them unless they push me too far. At least the net connection I'm getting is like I've never experienced before. Of course like I said, if this goes too far (like time differences changing) it might turn into a tricky issue. Afaik, the time gap has remained stable ince the beginning, but I'm not sure on that...just look around.


Senior Member
well we have been recommending on this forum that subscribers are to keep a watch on MTNL's clock which more often than not is ahead of the correct time.I for one noticed it the first day i got the connection. I keep a buffer of 15 mins for disconnection (7:45 AM) and 5 minutes for connection (12:05 AM) and never have my NU downloads been counted in the daytime limit.


Btw..where can we chk the time followed by MTNL? ie the MTNL clock as mentioned by cyberwiz? now dont ask me to google it


Senior Member
simple, keep ur comp clock upto date and connect to MTNL and note the time in ur comp clock. disconnect & again note ur time. Log onto ur account at MTNL and check the session history. The difference in the two recorded times will tell u how many minutes MTNL is ahead of u.Its easier in the Bridged mode but u can do it in the PPPoE/A mode as well by pulling the power plug of the router. Keep an eye on this difference and keep checking it if u are too paranoid. As mentioned above, I use a buffer of 15 mins & it has worked perfectly for me till now.


I am not going to remove my power cord dude...coz then you know what will happen :D


HiI am also facing the same problem. I have been online from 12/6/06.I checked the session report on the mtnl site upto 20/6/06 everything was ok as normally I use to surf and download at night after 00.15.On the 23/24 and 25 I happened to start the connction between 7.15am and 7.30am and switched it off always 5-10mins before 8.00am and to my surprise this has been charged. Luckily I did not dload anything and just surfed the web.One more surprising thing is that on 22/6 and 23/6 I had a long chat session with my relatives in UAEand this 2 days are missing from the session history. I chatted for almost 1hr.15min on both days.Thanksslacker


This seems to be a common problemHas anyone got a refund from MTNL for this problem or do you just quietly pay up?


Hmm...I connect at 0020, and disconnect at 0750, just to be on the safe side. A query: If I disconnect at 0805, is the entire nights usage counted in the 1 GB limit or just that from 0800 TO 0805? And no, I not too keen on trying it out and checking for meself. :p