Southern Cross Cable responds to Dick attack over 20-hour outage

Last week, CallPlus chairman Malcolm Dick told NBR he was concerned Pacific Fibre had folded, leaving the 50% Telecom-owned Southern Cross Cable as New Zealand's only high-capacity link to the outside world.

Dick said while Southern Cross' twin cable design had built in redundancy, he recalled a July 2001 incident (confirmed by a Southern Cross report to clients) during which one segment of the fibre optic link was down for maintenance, and other was taken out by a ship's anchor, which dragged through the cable in Sydney Harbour.

Some customers lost internet access for 12 hours, others for up to 20 after failover systems failed and it took half a day to physically reconnect the fibre.

More, looking at cable failure rate statistics per 1km of fibre per year, Dick estimated Southern Cross' meantime between failure was 15 years. Another outage could happen tomorrow, he said, which was a frightening prospect given the rise of broadband and the role of internet connectivity in the modern economy (in 2001, with most still on dialup, the outage didn't draw much attention - which seems amazing today).

Dick was also worried about the fact the cable runs near the politically volatile Fiji.

NBR gave Southern Cross the opportunity to reply last week, and it did on earthquake qualms raised separately by Orcon boss Scott Bartlett (here) but not Dick's failure theory.

Late yesterday, Southern Cross Asia Pacific sales director Ross Pfeffer came back with a response to the CallPlus chairman:

It follows:

2001 event

Mr Dick’s recall of the 12 hour loss of service in July 2001 is a little selective and does not reflect the capability of the Smart Figure 8 Southern Cross Network today.

Three important points to note in relation to the 2001 event will put it into perspective:

1.Protected traffic from New Zealand to both the United States and Australia was not impacted in 2001 [The Southern Cross Cable incident report from 2001, obtained by NBR, says, "Outage duration: Between 12-15 hours for protected traffic, Unprotected traffic up to 20 hours." The incident also highlighted that while Southern Cross offers full redundancy, not all clients will pay extra for that option - CK]

2.The outage was caused by a loss of the Trans-Tasman segment at a time when the construction of the Southern Cross network was incomplete (the Hawaii – Oregon segment was in the final stages of being re-laid to meet US regulatory requirements during the initial build phase of the network). 

3. Major network restoration enhancements have been implemented over the last 11 years to substantially reduce the risk of simultaneous dual segment incidents. We call this our Smart Figure 8 and one result, a simultaneous failure of the same segments that were impacted in 2001 would not result in a loss of service today for both Australia and New Zealand.

Since 2001 our network has been continually enhanced through implementations of the following initiatives:

1. New state of the art optical and electrical switching introduced to re-route traffic in the event of 66% of dual segment failure possibilities.

2. Over 2000 kilometers of new completely diverse terrestrial network in the US West Coast.

3. The introduction of Drop Restoration in 2008 at no additional cost to ensure that the great majority of Australia and New Zealand traffic to the United States actually uses our network’s ability to provide automatic protection.

Mean time before failure
We are unaware of the calculations behind Mr Dick’s assertion that the MTBF for the Southern Cross Network is some “15 years”.

Our calculations show that for the Southern Cross “Smart Figure 8” Network to have a MTBF of only 15 years, as asserted by Mr Dick, then his assumed per segment failure rate looks like one failure every 2 years.

Clearly not the Southern Cross system!

Indeed this is far higher than the segment failure rate experienced by virtually all deep water cable systems transiting the Pacific Ocean. It is also far higher than actual Southern Cross experience over 11 years. We have had 5 repairs from 7 submarine network segments over the period representing an average per wet segment repair rate of once every 15 years.  We have also averaged a 7 day repair time for wet segment failures and less than 1 day for terrestrial segment failures.

If our 11 year record for wet segments continues, the probability of dual wet segment repairs on the Southern Cross Network between now and 2025 resulting in a loss of service between New Zealand and California is less than 1%.

“The clock is ticking” as Mr. Dick says, but our calculations and Southern Cross experience show the clock can be expected to tick for a very long time because Southern Cross is now a “Smart Figure 8” Network.

Fiji
Another example of reported scaremongering is the assertion that the Southern Cross network is at serious risk in Fiji.  Again our experience suggests quite the contrary. Over the last 11 years there have been a range of political changes in that country and none have resulted in any hint of any risk to our Australia–United States cable that lands near Suva. In fact the Fijian Armed Forces have set up additional security to ensure that international communications are not compromised whenever there has been any hint of political instability.