HI Nick,
Regarding BSC Modules i'd say all modules have redundancy for all vendors and for an operator to purchase one without would be very foolish of them ......nway having cleared that up in this scenario the Tx link for MSC to BSC failed there is no recovering from that apart from having protected tx link to BSC

cheers 

On Tue, Oct 6, 2009 at 12:08 PM, Joe Murithi Njeru <joe.njeru@gmail.com> wrote:
<puke>
-----Original Message-----
From: Peter Karunyu <pkarunyu@gmail.com>
Reply-to: Skunkworks Forum <skunkworks@lists.my.co.ke>
To: Skunkworks Forum <skunkworks@lists.my.co.ke>
Subject: Re: [Skunkworks] Zain outtage??
Date: Tue, 6 Oct 2009 12:02:50 +0300

@Job, thanks to skunkworks, I can now take part in intelligent
conversations with intelligent people talking about intelligent sounding
stuff like ADMs, BSCs, MSCs and my ultimate favourite, DTMF! :-) If
skunksworks was a person, I would make him my best friend!


On Tue, Oct 6, 2009 at 11:28 AM, Job Muriuki <muriukin@gmail.com> wrote:
       Don't you love this list, all the tech stuff is very impressive
       anyway
       give Zain a breather. Look at the incumbent in there sector, it
       has
       all kinds of issues and Zain gets a rear tech hitch and you are
       quick
       to judge. It has the best voice service in kenya.


       On 10/6/09, David Kiania | Asentric Consulting Ltd
       <kianiadee@gmail.com> wrote:
       > It's not possible to comprehend the problem unless you
       understand the
       > GSM Architecture in the light of what Nick has offered to be
       correct
       > and heard the same from another reliable source. All Nairobi
       and
       > greater Nairobi all the way to Kajiado is handled by a BSC
       site in a
       > building within the CBD and is backhauled to Parkside where
       the MSC is
       > located via fiber.
       >
       > As part of the transmission design they have Add Drop
       Multiplexers
       > (ADMs) which provision STM connections depending on need and
       > protection to the MSC site or other locations. It's these ADMs
       that
       > failed causing the problem. This is would have been the case
       had it
       > been a physical fiber break and it reveals need for additional
       > transmission redundancy or protection as is commonly referred.
       >
       > It's not unusual for incidents like this to occur in normal
       operations
       > of a GSM network and we should not be very harsh on them. The
       loss of
       > business during this window is punishment enough.
       >
       > Kiania
       >
       >
       >
       >
       >
       >
       >
       >
       > On Tue, Oct 6, 2009 at 9:48 AM, nick muttai
       <nmuttai@gmail.com> wrote:
       >> Roy,
       >> True that, but all hardware modules in a BSC are totally
       redundant (either
       >> 1+1 or N+1 redundancy scheme) including the PCM interface
       >> boards, providing
       >> an automatic failover switch capability. This is true for all
       serious GSM
       >> equipment vendors. So the services dependent on these modules
       shouldn't be
       >> down that long especially for a big GSM provider like Zain
       and in
       >> locations
       >> like the CBD where the number of subscribers is humongous.
       >> This is all based on a lot of theory and a little bit of
       observation so my
       >> conjecture is open to correction.
       >> On Tue, Oct 6, 2009 at 9:15 AM, Roy Michoma
       <roymichoma@gmail.com> wrote:
       >>>
       >>> u cant have redundant BSC's
       >>>
       >>> On Tue, Oct 6, 2009 at 8:51 AM, Alvin Jason Ochieng
       <ajochola@gmail.com>
       >>> wrote:
       >>>>
       >>>> My line is also down & i have no bills pending !!! NKT !!!!
       >>>>
       >>>> On 10/6/09, nick muttai <nmuttai@gmail.com> wrote:
       >>>>>
       >>>>> A reliable source tells me that one of their their ADMs
       "died" Any Zain
       >>>>> guy to confirm this?And how comes they  do not have
       redundancy on key
       >>>>> BSC
       >>>>> components and services?
       >>>>> On Tue, Oct 6, 2009 at 8:21 AM, Jared Koyier
       <jaredkoyier@gmail.com>
       >>>>> wrote:
       >>>>>>
       >>>>>> SOLOMON....Surely do you think ZAIN anticipated an
       outtage at peak hrs
       >>>>>> and let it take course? Most technical faults are never
       seen apriori
       >>>>>> and it is unrealistic for a customer to be warned
       beforehand unless it
       >>>>>> is a scheduled maintenance. Dont fry zain,they lost more
       biz than
       >>>>>> majority of their subscibers due to that outtage.
       >>>>>>
       >>>>>> On 06/10/2009, Steve Muchai <smuchai@gmail.com> wrote:
       >>>>>> > On Tue, Oct 6, 2009 at 7:55 AM, Solomon Mburu
       <solo.mburu@gmail.com>
       >>>>>> > wrote:
       >>>>>> >> One strange thing, though, they didn't inform the
       consumers of an
       >>>>>> >> impending outage.
       >>>>>> >
       >>>>>> > there was never an "impending" outage, it was an
       unexpected outage.
       >>>>>> > They did send out an apology, thus acknowledging the
       incident,
       >>>>>> > though,
       >>>>>> > which I think is a good thing.
       >>>>>> >
       >>>>>> > BR,
       >>>>>> > S
       >>>>>> > _______________________________________________
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       >>>>>> >
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       >>>>>
       >>>>>
       >>>>>
       >>>>> --
       >>>>> Mwafrika
       >>>>>
       >>>>> _______________________________________________
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       >>>>> kazi:
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       >>>>
       >>>>
       >>>> _______________________________________________
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       >>>
       >>>
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       >>
       >>
       >>
       >> --
       >> Mwafrika
       >>
       >> _______________________________________________
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       >>
       >
       >
       >
       > --
       >
       > [Asentric Consulting Ltd]
       >
       > If a man has in himself the soul of a slave will he not become
       one no
       > matter what his birth ....
       >
       > -Richest Man in Babylon
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Regards,

Joe
Linux User: #361092
SIP: joe.njeru@ekiga.net