SINGAPORE: M1 has provided more details on the service disruption which affected customers from 15 to 17 January.
On 15 January, a vendor was carrying out upgrading works on the backhaul transmission network at one of its network centres.
At around 2.30am, the vendor attempted to connect its power cables from the transmission equipment rack to the distribution rack.
This caused sparks at the distribution rack, and resulted in both racks emitting smoke which caused the gas suppression system to discharge gas.
A water sprinkler was set off, causing damage to one of the mobile network switches, resulting in the service disruption.
To restore service, contingency plans for the core network was to increase network capacity and signaling links between all the other mobile network switches.
Plan A for the radio network was activated, with the radio network controller and its associated media gateway being re-linked to the alternative mobile network switch.
While the links were being re-configured, Plan B was activated.
This involved complex step-by-step restoration work including the reconfiguration of 416 base stations to the alternative mobile network switch, re-establishing communication links, and traffic rebalancing.
This was followed by comprehensive testing, including drive tests in the coverage area of each base station to ensure full call continuity for both voice and data services.
Plan B resulted in a total of 199 sites being connected by 3am on 17 January and Plan A completed the remaining 217 sites.
Partial 3G service to customers in the affected areas was restored on the evening of 15 January.
Restoration work for all affected sites was completed at about 3pm on 17 January and full service was restored at 6pm on the same day.
Plans to further enhance and improve network resiliency incorporating the latest technology commenced in the second half of 2011, with target completion date of mid-2013.
- CNA/xq
M1 provides details on service disruption & recovery
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M1 provides details on service disruption & recovery
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M1 provides details on service disruption & recovery
