Routed optical networks

Fri May 5 10:21:48 UTC 2023

On 5/5/23 10:54, Vasilenko Eduard wrote:

> 50GE is better just because it is half of the cost of 100GE and it is 
> enough now for the great majority of cases. Money is very important 
> these days for this industry. 100GE single mode is more expensive than 
> the best router port itself. Routers have been deprecated 10x for the 
> decade (almost 100x for 2 decades). Pluggable optics is not that much 
> deprecated.
>

Not sure where your pricing is coming from, but if I look at Flexoptix's 
50Gbps QSFP28 optics pricing, I am getting:

  * EUR724 @ 10km.
  * EUR1,246 @ 40km.

They are also selling an SFP56 LR for EUR925.

Juxtapose that against 100Gbps pricing:

  * EUR473 @ 10km.
  * EUR1,300 @ 25km.
  * EUR1,500 @ 30km.
  * EUR2,600 @ 40km.
  * EUR3,925 @ 80km.

Doesn't immediately seem to me that 50Gbps is cheaper than 100Gbps. 
There also don't seem to be as many deployments of 50Gbps in the metro 
(same could be said for 25Gbps and 40Gbps), but others on the list can 
chime in with what they are seeing/doing.

> I do not think that content provider guys call their DCI “Metro”, not 
> very often.
>

Well, whatever they call it, the concept is the same - move lots of 
traffic across town between data centres.

> I agree that 100GE for DCI is the minimum, 400GE is probably already 
> needed in some places.
>
> IMHO: it is a different story. Very interested too.
>

Most content providers have no choice but to run DWDM, for even very 
short spans between data centres. That is because it is just cheaper and 
simpler to pack Tbps of capacity in DWDM for the price than you can in a 
router. And besides, most routers don't need to carry Tbps of traffic in 
a single line card, which would be a waste of a fibre pair over that 
distance.

In such cases, better to use DWDM and drop capacity on individual 
routers and/or line cards as you see fit.

> PS: By the way, even if some ISP has 50% of revenue from Enterprise 
> services (it is probably the biggest number, typically 30%-40%), it is 
> still just 5% compare to residential traffic. Traffic to enterprises 
> is still sold 4x-10x (depending on the country).
>

That is why residential Access networks tend to be 2nd class citizens :-).

> Hence, Enterprise does not make sense to mention in the traffic 
> discussion. It is a “rounding error”.
>
> Enterprise business created a huge demand for oversubscribed ports to 
> connect Enterprises. And QoS/QoE. Not traffic.
>

Well, not all operators that offer enterprise services also do consumer 
broadband, or vice versa. To a network doing only one or the other, 
whatever traffic they are carrying means the world to them. It's not 
ours to decide what is high or low traffic... that priviledge always 
remains with the network operator.

Mark.
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