I asked a submarine guy how much the fibers can carry because this sounded low to me. His response: it depends on the type of cable. Older cables (with embedded dispersion compensation) have a lot less capacity and I have seen some as low as 1Tb/s per fiber pair and some as high as 10Tb/s per fiber pair. All newer D+ Cables that have been deployed in the last 5 years and will be the only cables deployed going forward can easily carry 20Tb/s of capacity per fiber pair. Something Like Havfrue can support 22T per fiber pair and there are 8 fiber pairs for a total of 176T. Barbara From: NANOG <nanog-bounces+bfox=ciena.com@nanog.org> On Behalf Of Mark Tinka Sent: Wednesday, January 27, 2021 7:13 AM To: Rod Beck <rod.beck@unitedcablecompany.com>; nanog@nanog.org Subject: [**EXTERNAL**] Re: Half Fibre Pair On 1/27/21 13:39, Rod Beck wrote: How much spectrum is a half fibre? It must be standardized in some fashion. It would be based on the amount of capacity each fibre in the overall system can carry across a given line system span. So say a cable system is able to carry 960Gbps per fibre pair, and it has 5 fibre pairs, that means a half fibre pair purchased by one of the consortium members would be 480Gbps. It is also possible for a consortium member to own a full + a fractional fibre pair, e.g., two and a-half fibre pairs. In such a contract, for example, say a 24 fibre-pair system could carry 1.2Tbps per fibre pair, that member would have 3Tbps of capacity. Mark.