21CN cheaper than 20CN?

Is it cheaper for ISPs to provide broadband to their customers on 21CN when compared to 20CN?

I don't know the numbers, but I believe so yes - AAISP offer twice the amount per "Unit" for 21CN customers to those on 20CN.

Yes.

However the main gain in BT prices is if the ISP opts for WBC, where they have to pick up their traffic from all 20 WBC nodes. The ISP needs to be big to swallow the direct costs and overheads of that approach.

WBMC pricing is higher than WBC but the ISP can pick up at one node, so only needs sufficient MSIL capacity and backhaul there to handle its customers, as opposed to 20 MSILs and associated backhaul on WBC.

An MSIL performs roughly speaking the same function as BT Centrals which are not used on 21CN, but is located at or near the WBC node(s).

The capacity contracted on an MSIL can be varied, and if 100% of contract is reached then BT allow the excess traffic through but at a higher charge per MB. Unlike centrals when if you reach the lit capacity you are stuck. Assuming of course the MSIL has spare capacity. The smallest is I believe 1Gbps, and I expect the 10Gbps ones are now available.

Edited by RobertoS (Fri 25-Jun-10 23:18:26)

Yes, mainly because you can buy capacity in much smaller increments rather than the slightly lower per unit cost. This means that the ISP can build capacity over time rather than having to invest well ahead of the curve.

Hi James

A question I've asked a couple of times from people and never got a simple answer, and there has to be one.

On WBMC an ISP can pick everything up at one node instead of the full 20 that WBC ISPs have to do. But can a WBMC ISP pick up at say 2 or 3 nodes, perhaps around the country?

On a similar tack, I assume 10Gbps MSILs are now available. Can an ISP upgrade from one 1Gbps MSIL by adding another one or two, or do they have to replace it by a 10Gbps one? Or do the prices make the choice automatic?

Which raises the interesting question of how would a 1Gbps be replaced by a 10Gbps without high risk at switch-over?

Edited by RobertoS (Sat 26-Jun-10 16:38:34)

WMBC consumes IPSC and WBC to deliver a central like product so you can have as many nodes as you want, delivery of customer X to node Y is still fairly random so Scottish customers could be delivered to your London rather than Glasgow node...

Choice of MSIL size is an architecture question that depends on the hardware you are using rather than there being a single answer. 2 MSILs is always safer the 1 big one in general...

Edited by boggits (Sat 26-Jun-10 17:38:30)

Thanks James .