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Agent Newsletter-Dec 2009-Part 4

Posted on Dec 17 in Agent, O-TELby Press OfficerPrint

Last Mile Connectivity

Most fault reports coming in are of: Bad call quality, and calls cutting.

O-Tel servers are monitored 24/7/365. We have preventative measures on it too. Should something happen at server level, we always have other servers to forward calls to, or preventative maintenance measures to avoid downtime.

The above common reports are due to South Africas poor Last Mile Connectivity service and Telkom’s greatest weapon to retain market share.

I have jotted down a list of things to do should you have such reports.

For Voice Quality issues:

  • If Customer is using standard DSL, upgrade the line to a faster one.
  • If after upgrading, there is still quality issues, then upgrade to VLL.
  • If VLL still causes problems, then submit the MAC ADDRESS of the router (you should keep a record of every VLL router you send out there and their MAC addresses as well as concurrency). We will examine the throughput and see where the problem lies.
  • Should the ADSL not be stable enough to use VLL, then try VLL2, taking 2 (or more) broadband connections, either DSL, Iburst, 3G etc and make one virtual pipe to O-Tel. This will spread the risks of the call amongst multiple broadband connections, thus improving the data throughput.
  • If VLL2 still fails, then try Diginet.
  • 64k = 3 ccc, 128k = 6ccc, 256k = 12ccc and so on.
  • If Diginet is not available in the area or taking too long to install, then we can try a microwave link. Contact O-Tel for references.
  • If the above proves too costly, then find a local WIFI internet supplier and contact us for negotiations.

It’s always last mile connectivity issues. We need to find the right one in the area.

Don’t forget the fact that (like any IT equipment) a VLL router CAN GO FAULTY!!! If it was working fine before, and all of a sudden, no longer working, check the router..(send us the MAC ADDRESS to check).

Each normal ADSL connection/line has a best effort service… which means that:
In an ADSL exchange (aka DLSAM) a client has a 1mb service= 512kb Synchoronous….

At best effort, during off peak times, the client will get approx 478kbs (good service)….and at peak times, or if the exchange is full, the client will get about 256kbs….the exchange will allocate ALL 1MB LINES on this exchange this 256kbs speed… everyone gets equal share…this is called BEST EFFORT SERVICE without SLA.

Now if you applied by Telkom for a 512kbs sync (1mb async), and they allocate you 256kbs at bad times or at busy exchanges, you will get bad call quality, calls cutting etc. even if you’re using VLL. The pipe they’re giving you is just too small to handle the calls.

Now, if we get two ADSL lines, and at peak times both offers this 256kbs speed, VLL2 takes both these lines, combines them together, and makes it 512kbps. SO ideally, at the worst times of Telkom service, you should at least get twice the speed any other Telkom client on that exchange…as you’re truly using up two NODES instead of one…and VLL2 is the only technology which combines the pipes AFTER Telkom exchange.

Ok, saying that:
You can add upto 4 concurrent broadband connections. So if you want to add to the VLL2 router 2x ADSL, 1x IBURST(check whats their upload speed) and 1x 3G…you can! Just add up all the upload speeds… eg:

ADSL1= 512kb at good times
ADSL2= 512kb at good times
IBURST=256kb at good times
3G= 512kbs at good times
Total = 1792kbps upload speed………..VVL2 pipe is 1792kbps!!!

Now if you only get 50% service on this, you still get 896kbps!!….
FURTHERMORE!!! If your two ADSL is DOWN, you still get 768kbps pipe via the other broadband connections! IF ADSL is busy and the pipe goes narrower, the VLL2 router pushes the voice to the other broadband connections.

ALL THIS IS cheaper than DIGINET!

Now, VLL and VLL2 is a proven technology in UK, as they faced the same problem we currently have, 6 years ago…. It should work in SA.. if not, then DIGINET is the route to go..

Frankly, I have visited 4 countries this month, and I have not had a single delay of a millisecond on any call I made trough O-Tel…the Last Mile connectivity in Europe is so much more superior, its unbelievable.. I’ve seen 36 concurrent calls on a 1MB ADSL VLL enabled line, flawless!!

Telkom is holding us back. I’m working very hard on getting other LMC solutions…there’s many good LMC solution in the pipeline..but everything takes time, South African companies are very laid back…

Some important notes on LMC

  • There is absolutely no SLA or service guarantee on ADSL. Say a SOHO service is 4mb, but upload speed is sometimes 128kbps, which means that the sync is only 128kbps pipe!
  • Speed depends on congestion… Telkom has no money to make the exchanges bigger. They talk of 8mbps ADSL lines, but they cant even cope with 4mb…(my personal opinion)
  • A call requires 22kbps, but this is not workable when using VLL. VLL shapes all bandwidth according to environment.
  • Async using VLL
    128kps = 12ccc
    256kbps= 22ccc
    512kbps= 45ccc

Test results during my recent travels in Europe.
In Bucharest, Romania, I got 217ms to the O-Tel Server, clarity was Excellent.
Zurich 203ms, clarity was Excellent.
UK, London 364ms, clarity was Excellent.
UK, Leicester 467ms, clarity was good.
Blackburn 503ms, clarity was good.

Hence the problem we face in South Africa is LMC………..the latency might be low, but contention is high. The result is SA lagging in digital telephony compared to the world.

Here in Zurich, its 100 digital telephony… UK is 95%, Romania is 75% digital telephony.

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