Problems with MTN GPRS

S

ScrnScrm

Expert Member
Joined
Mar 18, 2005
Messages
1,230
Reaction score
14
Location
France
Hi MTNBB
I have started experiencing problems with the MTN GPRS/EDGE service, and was hoping you could shed some light on some of them :

a. I can no longer VPN back to the office via the "internet" APN. When was this closed again? I have tried from two different SIM cards. Your post has reference:

http://www.mybroadband.co.za/vb/showpost.php?p=185750&postcount=105

I thought this was permanent?

b. This wouldnt normally be a problem for me, as we have a corporate apn solution. So I have tried to connect via this. Alas, I have now discovered that the corporate APNs are no longer provisioned across all towers that have GPRS/GPRS&EDGE. There are blind spots all over the show (Jhb AND Cpt Airport for starters). Experienced blind spots in Durban, PE and East London during the last week. I can connect to "internet" APN fine in these areas - just not the corporate APN. I have checked with our help desk and found that all our users are experiencing this problem, so its not my handset. Phoned a mate who works for another company that also has an APN, and alas, the same problem.

c. As of yesterday afternoon, everytime I get an incoming call whilst connected to GPRS, it drops my connection and doesnt restore it automatically on completion of the call. Again, tried on a different SIM/Phone and same problem. This is even worse on the corp apn as it totally buggers up the ssl tunnel I use to synch my mail. *grrrr* very irritating.

d. Thoughput has gone to the dogs during the last ten days. Its after 12 in the evening in a quite suburban Sandton suburb and I am battling to get over 80Kbps. It occasionally bursts to 100kbps, but not faster than that. Considering that a month ago I was getting close to 200kbps at times, it begs the question - WHAT HAS CHANGED? In PE in particular the response was really bad. Durban was about the same. Last Monday in Cape Town (from home, which is admittedly close to the tower) I was only getting 115Kbps.

So, some more questions :
Have MTN throttled back the amount of channels available for download to 2, or changed the coding schemes? i asked our customer services rep and he said, "eh, could well be" but he couldnt confirm or deny. I would greatly appreciate it if you could. What is the FINAL story on the VPN over "internet APN" solution. Are you are arent you guys going to allow it? And why wasnt this communicated!!!!!!!

I would really appreciate some feedback from you wrt these issues, as a LARGE portion of your user base is starting to experience them first hand. I think you need to nip this in the bud right now!

Thanks -
 
ScrnScrm said:
Hi MTNBB
I have started experiencing problems with the MTN GPRS/EDGE service, and was hoping you could shed some light on some of them :

a. I can no longer VPN back to the office via the "internet" APN. When was this closed again? I have tried from two different SIM cards. Your post has reference:

http://www.mybroadband.co.za/vb/showpost.php?p=185750&postcount=105

I thought this was permanent?

b. This wouldnt normally be a problem for me, as we have a corporate apn solution. So I have tried to connect via this. Alas, I have now discovered that the corporate APNs are no longer provisioned across all towers that have GPRS/GPRS&EDGE. There are blind spots all over the show (Jhb AND Cpt Airport for starters). Experienced blind spots in Durban, PE and East London during the last week. I can connect to "internet" APN fine in these areas - just not the corporate APN. I have checked with our help desk and found that all our users are experiencing this problem, so its not my handset. Phoned a mate who works for another company that also has an APN, and alas, the same problem.

c. As of yesterday afternoon, everytime I get an incoming call whilst connected to GPRS, it drops my connection and doesnt restore it automatically on completion of the call. Again, tried on a different SIM/Phone and same problem. This is even worse on the corp apn as it totally buggers up the ssl tunnel I use to synch my mail. *grrrr* very irritating.

d. Thoughput has gone to the dogs during the last ten days. Its after 12 in the evening in a quite suburban Sandton suburb and I am battling to get over 80Kbps. It occasionally bursts to 100kbps, but not faster than that. Considering that a month ago I was getting close to 200kbps at times, it begs the question - WHAT HAS CHANGED? In PE in particular the response was really bad. Durban was about the same. Last Monday in Cape Town (from home, which is admittedly close to the tower) I was only getting 115Kbps.

So, some more questions :
Have MTN throttled back the amount of channels available for download to 2, or changed the coding schemes? i asked our customer services rep and he said, "eh, could well be" but he couldnt confirm or deny. I would greatly appreciate it if you could. What is the FINAL story on the VPN over "internet APN" solution. Are you are arent you guys going to allow it? And why wasnt this communicated!!!!!!!

I would really appreciate some feedback from you wrt these issues, as a LARGE portion of your user base is starting to experience them first hand. I think you need to nip this in the bud right now!

Thanks -
Click to expand...

Gee this is a long post so I'll give some answer and come back later with more:-

The VPN service has not been discontinued and is most likely the effect of a firewall change. This will be looked at tomorrow. There is a plan to put in a dedicated firewall to minimise this type of disruption. We are also lobbying internally to set up our own vpn access service for staff so we can eat our own breakfast.

The base stations have no idea which APN you are connecting to so they don't typically discriminate.

The point of private (corporate) APNs is that as a corporate you should have leverage to lean heavily on your ISP who in turn should lean directly and heavily on our own first-level support. That is how we set up the escalation processes with the ISPs to ensure the fastest response times. Send me a private message with your ISP details and I will reprimand them for not escalating aggressively enough to us.

The handling of GPRS and voice calls is a GPRS protocal issue and is also subject to slight variations with each handset. Handsets are 'Class B' which means they do not support "dual sessions" - ie Speech and GPRS connections simultaneously. If there is an incoming call whilst data is actually being transferred, an incoming call will receive a busy tone. If there is no data being transferred and GPRS is 'idle', when a call comes in or when you dial out, the GPRS session will be suspended and can later be resumed. However some handsets do disconnect and applications sometimes time out during the call.

In terms of lower data speeds - we have not changed anything to reduce data speeds. I am not sure if this is the explanation, but the traffic has picked up enormously since the tariff reduction. We delayed the introduction of new tariffs to beef up the network in preparation, but the growth as always does tend to be unpredictable and uneven. We are talking 2 million potential GPRS users and 300 000 potential EDGE users scattered around the country and a good number able to experience affordable data and broadband for the first time with the devices already in their pockets! There is a time lag between ordering back-end links and actual installation which is not completely within our control and we have been feverishly ordering links for some months now so this has a bit of a time lage. WAP traffic (for example) has doubled to over 1 mbps just on the international bandwidth, and this usage does extend until after midnight. Similarly EDGE users have suddenly started moving significantly higher traffic and prepaid users (for instance) have full internet access.

I hope that goes some distance to answering the list.
 
Hi MTNBB
Thanks for your response. I will PM you the details shortly for our APN.
I will also post in this thread which base stations I am using and what Coding Scheme I am getting for information purposes to the general community online here so that I can see if anyone else is complaining or if its just me.

If fully understand the backhaul line installation issues - we have a similar problem on our corporate network :D

Wrt the handset disconnecting - I am aware that it should give a busy signal during downloads, but for some strange reason it wasnt yesteday. Tested it now again quick and its back to normal. Strange?....

Wrt the huge uptake of users - roll on 3G!

Thanks -
 
Well besides things posted here that I havnt experienced, my gprs on edge enabled tower is rocking. Im very impressed with the price and performance :)
 
I haven't experience EDGE speeds yet, so when I came to Sandton on business today I thought I was going to be in for a joyous time. Unfortunately in my hotel in Katherine Street, neither MTN or Vodacom seems to have decent signals ... I can almost forget to have voice conversations, SMS obviously works OK and data ranges between 10 and 20 Kbps...but drops frequently. <grin> and this about a kilometer from the MTN head office.

I guess it's the topography around here? The towers I am seeing on info channel 900 are:

1540C/MEDICAL MEWS (GRAYSTON)
1559A/MOORPARK
1559B/MOORPARK
1171C/MEMBRANE SWITCH TECH

Maybe MTNbb can arrange that they upgrade the service in this area for a few days. LOL

I guess the only way to get out of these situations is to use an antenna? But neither my 6230 or 9500 seems to support external connections as far as I can see.
 
Hi MTNBB
As promised, here are my current BTS details :
Network Code : 10F
Location Area : 4202
Serving Cell Indentifier : 8562
Serving Cell Channel # : 101
EGPRS support = 1
BEP Period = 255
Download Time Slots = 2
Upload Time Slots = 2
Signal Strength = -71

In the past, I could get 4 download slots no problem. I havent seen more than 2 download slots for over a week now. This means that I am limited to a throughput of 2 x 59.2Kbps (118K). I just tested this now and managed to get nearly full speed through the two time slots (about 110k). On standard GPRS I get 4 download slots (tested via a GPRS only cell phone) on the same base station.

Can I assume that EDGE has been throttled back to 2 time slots, at least in this area?

Do I need to post some more BTS info so that you can get your engineers to have a look in case their is a problem?

Later -
 
Thanks for the detail on the Sandton site.

The specific problem with that site is the capacity of the backlink and they are already aware of the upgrade requirement. It works on GPRS because GPRS requires less than one 64 kbps backlink for all 4 timeslots whereas EDGE hogs as many as 4 for one user.
 
how can i get an edge pcmcia modem? iburst is cancelled and i want to switch to mtn today...
 
Wow

MTN take this site seriously... hmmm... i may just be tempted to say nice things about them...
 
When did MTN drop their service charges

And why aren't they agressively marketing this new change of plan? I haven't heard it anywhere but on this site so far - cant even find it on the mtn.co.za pages... ?

Aha... found it before posting...
http://www.mtn.co.za/?pid=11468

Can anyone tell me the theoretical throughput of bog standard GPRS (no edge)?
 
EdRobinson said:
And why aren't they agressively marketing this new change of plan? I haven't heard it anywhere but on this site so far - cant even find it on the mtn.co.za pages... ?

Aha... found it before posting...
http://www.mtn.co.za/?pid=11468

Can anyone tell me the theoretical throughput of bog standard GPRS (no edge)?
Click to expand...

This has been discussed but no problem going through it.

GPRS has two parameters - the coding schemes used and the 'timeslots'.

The coding sheme is selected between MTN and the handset depending on the radio quality.

Coding scheme 1 is 8.0 kbps per timeslot and is for the poorest radio conditions.
Coding scheme 2 is 12.0 kbps per timeslot for slightly better conditions.
Coding sheme 3 is 14.4 and CS4 is 20.0 kbps per timeslot.

When MTN rolls out EDGE in an area, it also rolls out Coding Schemes 3 and 4. These are supported on 98% of handsets in the market. In other words - to get these higher speeds of CS 3 and 4 via GPRS you must be using MTN (to-date) and you must be in EDGE coverage.

Some handsets support 4 x timeslots downlink and 2 x timeslots uplink so you get

4 x 20.0 = 80.0 kbps downlink
2 x 20.0 = 40.0 kbps uplink

Most handsets support 3 down and 1 up.

These are the air interface speeds so as with any radio technology you take off around 5-10% for radio protocol overhead, re-transmissions etc and more for other contesting users etc.

Why we haven't been selling aggressively - we are going for basic EDGE coverage consolidation and improved customer care knowledge before going aggressive.
 
Just got this information from mobile-phones-uk.org


GPRS Class

Slots

Max. data transfer speed
Class 2

3

8 - 12 kbps upload / 16 - 24 kbps download
Class 4

4

8 - 12 kbps upload / 24 - 36 kbps download
Class 6

4

24 - 36 kbps upload / 24 - 36 kbps download
Class 8

5

8 - 12 kbps upload / 32 - 40 kbps download
Class 10

5

16 - 24 kbps upload / 32 - 48 kbps download
Class 12

5

32 - 48 kbps upload / 32 - 48 kbps download
 
I just realised reason im getting rather good speeds on my nokia 6260, it seems to have 4+1slots :_)
 
Why we haven't been selling aggressively - we are going for basic EDGE coverage consolidation and improved customer care knowledge before going aggressive.
Click to expand...

Really good to hear that.
 
Bugsy said:
How does one get one's current BTS details?
Click to expand...

depends what phone u have. i have nokia field test software that runs on symbian series 60 phones. if you have a series 60 phone, its simply a matter of loading the sis file on voila, all the info u need is available.

pssst -> there is also some neat software that allows you to force your channel/base station, so if you are roaming onto an old gprs only base station but are within range of an edge one, you can force and edge connection.. but i never told u this :D
 
ScrnScrm said:
depends what phone u have. i have nokia field test software that runs on symbian series 60 phones. if you have a series 60 phone, its simply a matter of loading the sis file on voila, all the info u need is available.

pssst -> there is also some neat software that allows you to force your channel/base station, so if you are roaming onto an old gprs only base station but are within range of an edge one, you can force and edge connection.. but i never told u this :D
Click to expand...

Please advise how I can get to play with the Series 60 software to do the cell checks and to force the cell.

The EDGE data speeds should have been increased this morning for the specific cell and sector you mentioned yesterday in Sandton.
 
ScrnScrm said:
depends what phone u have. i have nokia field test software that runs on symbian series 60 phones. if you have a series 60 phone, its simply a matter of loading the sis file on voila, all the info u need is available.
Click to expand...

ScrnScrm, does the 6230 fall in this category?
 
You must log in or register to reply here.
Back
Top
Sign up to the MyBroadband newsletter
X