I've decided to get transit from provider B independently of A, so I don't create a conflict of interest as mentioned below. However I think that I will have to use provider A's dark fibre network to connect to both peerings. Provider A tells me that they will use different routes and different entry points to get to their peering and separate routes, entries to get to B's peering. As they own the datacentre and can probably provide the bests costs for getting into the datacentres where the second transit provider is, I think I will have to use
I should mention there are no transit providers on net at the datacentre facility which has been acquired by the business. I suspect it will be cheaper to get the cross connects to where the transit provider is from provider A, (did I mention provider A owns the datacentre?). I know I'll be sacrificing some resilience by using A's network to get to both Internet services, however I think I will just have to outline the risks to the business and go with it. Moving datacentres isn't an option and as long as I understand exactly what resilience I sacrifice by getting A to provide all the cross connects, I can explain that to the business.