8CIOReview | | JUNE 2021IN MY OPINIONFAST SPEEDS AND LOW LATENCY ­ BUT WHAT HAS RELIABILITY SLIPPED IN TELECOM NETWORKS. By Rohit Narayan, Global Director, Telecom, nVentIn the 1980's if one made a phone call or for that matter a Telex call there was almost a 100% certainly that that call would be completed successfully. I was involved in the design of telecom facilities and each facility would be designed with 10 hours battery back time using flooded cells that would last more than 20 years. Yes the calls could sometimes be a bit noisy, you could get occasion cross talk but hey, the reliability was never compromised. As we moved to voice in cellular networks we have been taught to have lower expectation and even today some 30 years later, as a consumer we accept, that some phone call will not be completed and we just try again if a call drops off. Having mobile voice service was so liberating but we saw that reliability was somewhat compromised. We also started to see cellular sites having smaller battery back up times of 1-4 hours as a contrast to early days. Move then to fixed and mobile data communications and packet switching. Well what the heck, it is just packets of data that need to be reassembled on the other side. If we don't transmit it all, we can just re-transmit. Packet switching gave us a great ability to transmit all the data intact eventually and in some cases we began to pay less attention noise and bit error rates. If the bit error rate is high it just results in re-transmission until all packet are received on the other side. How many times
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