Publicly, Vodafone has maintained a diplomatic silence about the XT outage [At least until Monday when it unveiled its EXIT series of ads - CK].
But an internal memo obtained by NBR outlines (cough) points that staff should raise if asked about network reliability by customers, friends and family.
READ ALSO: XT restored; wait starts for compo
The note mentions how Vodafone’s 2G network can act as a fallback if its 3G network fails, while Telecom’s older CDMA network can’t be used with an XT phone (although Telecom has issued some affected XT customers with CDMA handsets).
That’s true enough on paper - but in the case of at least one Auckland mini-outage, Vodafone’s 2G network became overloaded.
It also brings up the thorny issue of RNCs - the big bits of kit that control voice and data traffic on a network (Telecom has one in Auckland controlling traffic north of Taupo, and one in Christchurch controlling traffic south of Taupo).
Telecom has both downplayed Vodafone’s numerical advantages in RNCs - pointing out one UK telco has four for the entire country - and said it’s buying more, the better to deal with increasing numbers of XT customers.
At the time of Telecom’s December 14 outage, Vodafone had five RNCs, now it has six.
The war of word over RNCs will continue. Telecom says each has multiple redundant systems. However, failure can obviously happen, and the more RNCs you have, the smaller the geographical area affected by each outage.
Ultimately, Telecom’s best rebuttal is to get XT back online, countrywide, and not suffer a third outage.
To: "DG-NZ-All Staff Vodafone & Contractors NZ" [snip]
Subject: BBQ chat - Networks for beginners
From Mike Davies, GM of Networks and Services:
There has been significant media coverage this week of Telecom's XT network service disruptions for customers south of Taupo. Whilst it is evident that they have been working frantically to bring services back online for their customers it is the second major disruption for XT customers in six weeks and it is likely that you will face questions from customers, friends and family as to why this has happened and what steps does Vodafone take to mitigate the risks of this happening on our network.
Vodafone New Zealand’s network build started 15 years ago under Bell South with our original 2G network – GSM. That network is still working today and every Vodafone mobile will fall back to using this network should anything outrageous happen to our 3G network.
This gives us a tremendous level of robustness because customers can carry on working through all but the most severe of outages. To date we have never had an outage on the scale seen by Telecom
Here’s how our network works – apologies for the techno speak.
At its core the Vodafone network is connected together via a number of elements, one of the most critical is the “radio network controller” (RNCs).
These link the 3G cell sites into the network. Vodafone has six RNCs that look after calls for various geographies, spreading the load across the country. Any individual RNC failure is limited to that area. We understand that Telecom has 2 RNCs. Clearly in that situation a large area is impacted.
As a reminder in the highly rare event we have an issue with our 3G network, customers seamlessly transition to the 2G network. Calls and TXTs would continue to flow – the most significant difference would be for our data customers reverting to GPRS and thus would drop back to dial-up speeds.
Because we’ve been in this game for so long we’ve invested heavily in making sure our network is able to withstand outages at every level. Our network has been described as a patchwork quilt, but in fact it’s layers upon layers which mean should something go wrong at one point, we have a depth of capability to minimise customer impact.
I appreciate that you’re likely to get questions about the outage and how Vodafone would fare and I can assure you, our network is built with robustness and capacity building in mind. We’ve been expanding our capability as customers take up mobile broadband devices in huge numbers and we’re well placed to make the move to higher network speeds with HSPA+ capability already on offer in central Auckland. With this information you should feel confident to reassure any friends and family about the reliability of the Vodafone network.
Have a great weekend.