Dark fibre vs Layer 2 WAN ?

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tedauction

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#207557 2-Jan-2017 15:10

Hello, can someone please explain the difference between a layer 2 WAN circuit and a dark fibre circuit (in the context of a business here in NZ requiring site to site dedicated network links)

Thanks kindly.

sbiddle

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#1697624 2-Jan-2017 15:24

A layer2 circuit has electronics and is normally a managed offering, so you basically have an Ethernet port at each end.

A dark fibre circuit is exactly that - a piece of fibre that runs from one point to another. You need to provide electronics for each end.

BarTender

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#1697627 2-Jan-2017 15:30

In the Spark terms a DFAS (Dark Fibre Access Service) is a port directly plugged into a OTN node and will be the most expensive offering as it's fully dedicated end to end and less managed as path diversity doesn't tend to be offered unless you want to pay for it.
The Layer 2 service a Carrier Ethernet node would be deployed typically with an 8 port access switch that is fully managed where the speed can be ramped up and down depending on how much you want to pay.

tedauction

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#1697632 2-Jan-2017 15:42

Thanks, I know we don't provide any "electronics'' so to speak, to light the fibre up (Vodafone provided).

So I presume in our case, dark fibre just refers to a link which is faster and fully dedicated compared to a L2 WAN ?

Would you agree ?

Also when you say that an L2 WAN is fully managed, but dark fibre not, what sort of management are you referring to ?

Thanks kindly.

richms

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#1697635 2-Jan-2017 15:53

Because you cant really manage a pipe that you stick light thru, light in one end, out the other end basically. Up to you to attach whatever you like to it. Just like the optical cable that used to be used in home theaters. No electronics, no configuration.

Richard rich.ms

sbiddle

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#1697638 2-Jan-2017 16:04

tedauction:

Also when you say that an L2 WAN is fully managed, but dark fibre not, what sort of management are you referring to ?

Well it's a L2 connection so the provider can manage the endpoints at both ends, control the speed, and capabilities of the circuit. Because of this they can also monitor outages.

Doing any of those when you're just provided with a piece of fibre that you have control over is rather difficult.

tedauction

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#1697656 2-Jan-2017 16:16

thanks guys, I understand.

But I am sure we don't provide any '"electronics"at either end. We would simply plug a Cisco switch in to the optical transceiver. Is this all that is required ?

Also, are dark fibre links cheaper or more expensive than L2 WAN circuits ?

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richms

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#1697707 2-Jan-2017 17:11

Who pays for the optical transciever? If you, then its dark, if the telco providing fiber then its managed.

Richard rich.ms

noroad

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#1697719 2-Jan-2017 17:32

tedauction:

thanks guys, I understand.

But I am sure we don't provide any '"electronics"at either end. We would simply plug a Cisco switch in to the optical transceiver. Is this all that is required ?

Also, are dark fibre links cheaper or more expensive than L2 WAN circuits ?

Dark = Glass only, nothing in between. I.e. you need an appropriate optical transceiver (or OTN platform for long distance) to light it. Dark fiber is normally used by a carrier/service provider rather than an end user (unless the end user has a depth of optical transport knowledge, or if its very short links). I would suggest if you need to ask, then dark fiber is really not for you, a managed service will be better suited as its guaranteed to work and normally includes things like core diversity.

sbiddle

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#1697736 2-Jan-2017 18:44

tedauction:

Also, are dark fibre links cheaper or more expensive than L2 WAN circuits ?

The only realistic answer to that is "depends" because it's both depending on what the requirements are, and where it's between.

webwat

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#1697882 3-Jan-2017 14:32

tedauction:

Hello, can someone please explain the difference between a layer 2 WAN circuit and a dark fibre circuit (in the context of a business here in NZ requiring site to site dedicated network links)

Thanks kindly.

Dark fibre isn't actually a circuit because its unlit, ie no electronics at each end. The idea is that you get it linked to another premises and put your own connection at each end. Layer 2 WAN is an Ethernet link (probably including a VLAN and an agreement for other traffic management settings) so its got a network between the 2 or more end points of the link.

Time to find a new industry!

vulcannz

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#1698177 4-Jan-2017 08:44

I have seen certain telcos sell a "Layer 2 WAN" with no support for VLANs or other layer 2 capabilities. You need to make it clear what your requirements are (and even then you find the sales people simply nod their head anyway).

If you do use a Layer 2 WAN service you also have consider your security requirements as you are exposing your internal network to the telco. Some people won't care, others will.