Why people are talking about photonic layer
Heather's links are nice and I also recommend the course.
My work takes me into the 'photonic layer' weekly. Of course there are different configurations but I can give you some simple configs and general information as we use Ciena's equipment in our Edge to core type network.
You can consider the photonic layer as the Network side of a Network/client relationship, although the 'client' side I make an analogy of is not really a true customer side but does point to the end users direction. For example, we usually have 1 or 2 photinic shelves and a 'broadband' shelf at 1 site. The broadband shelf has 1G,10G and 100G handoffs which would be connected to remote customer sites via short to medium fiber optic lines (1 to 20 miles). That broadband shelf would 'upstream' to the photonic shelf where all services would be aggregated and linked to other photonic shelves in other central offices,colocations, point of presences etc. Those connected photonic shelves create the backbone network. The "circuits" working between these photonic shelves are called 'degrees' and carry VERY large bandwidth. Now while my description above has separate photonic and broadband shelves, we also mix photonics and broadband equipment in the same shelf depending on our situation.
The photonic shelves consist of wavelength switching cards and amplifier cards to amp the degree to the other offices/POPs. Again this is a simplified example and you would have other cards like DCMs and also filter shelves (CMDs). Degrees can drop/add at these locations or pass thru to other CO/POPs in a mesh config. This is a simplified description and is typical for ROADM networks. Ciena or other. Ciena's photonic layer is pretty amazing and worth reading up on with its self optimization and intelligence.
So the photonic layer basically aggregates, optimizes and switches wavelengths upstream of the client ports/side.
Hope this helps,
Hi Surender, as you wait to hear from others in the community, I wanted to shared this data sheet on the topic with you: Common Photonic Layer product data sheet - Ciena. I'll also reach out to Ciena SMEs to help answer address your question too. Stay tuned and please update this thread if you have any additional questions in the interim.
Surender, I also wanted to pass along this link to a Ciena Learning course that you may be interested in enrolling: Common Photonic Layer Overview. Below is the course description and please note that this will require an account on our course site.
Get an overview of the Common Photonic Layer (CPL). This overview course describes the basic applications of the CPL product family, modules, configurations, other related hardware, and includes an overview of the management platforms.
Identify the use of Optical Transport Section (OTS) and Adjacencies
Candidates for this course include telecommunications professionals and anyone who requires an overview of the Common Photonic Layer (CPL).
Hope this helps.
Thanks for explanation,
Photonic layer is ROADM network if i understand right from your answer.
If roadm card not used in network then it not a photonic layer and its a simple DWDM network.
Yes I would agree with that. I do have 40 channel DWDM systems that do just that in a point to point configuration without any switching, adding or dropping.
As Joe mentioned, photonic layer includes modules like the CMD44, WSS and Amps. While the broadband layer includes all the transponder modules, 10G, 40G and 100G. Depending on how you configure your network, a photonic system can be a ROADM or a TOADM system. Difference between a ROADM and A TOADM system is that the ROADM have the capablility to switch traffic to a different direction or degree. TOADM system do not use WSS but still have the CMD44 and the amplifiers. All mentioned system are DWDM systems since they are transporting not just a single wavelength but multiple wavelenghts either in a 50Ghz or 100Ghz channel spacing.
I hope this helps.
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