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Optical ASON or Electrical ASON!

The debate still lingers on. When it comes to protection and re-routing  on High speed links, what is the benefit of using Optical ASON versus Electrical ASON.

The Optical ASON relates to lambda switching ( Also called WSON-Wavelength Switched Optical Network). This necessitates the need of using at  minimum Multi degree and directionless functionality. Using colorless functionality gives more degree of freedom and flexibility since in case of non-availability of a particular wavelength, ROADM has the functionality to change the color of wavelength also. When it comes to Electrical ASON, it is referred to as “ODU switching” at electrical layer of OTN switch. This necessitates the use of OTN switch along with ROADM. While Optical ASON gives one an advantage of lambda switching; the Eletcrial ASON gives advantage of control over more granular traffic at ODU level going as low as 1G traffic. In contrast, lambda switching can help to save on transponder resources because the same transponder can change direction or color thus there is no need to have multiple transponders for multiple restoration paths-a  benefit not available on electrical ASON which would need multiple lambda paths to be created from Day one. Electrical ASON on the other hand gives much faster restoration times compared to Optical ASON. So what is the verdict ?

The rule of thumb is following: If traffic granularity is less and the lambda is not filled completely, Electrical ASON is much more optimized and cost efficient, on the other hand if lambda is filled with traffic ( multiple ODUs occupying complete lambda)  that needs same SLA of restoration ( Meaning complete Lamda needs to be switched) then Opitcal ASON is much more optimized and cost efficient and ends up saving on the number of transponders.

29 thoughts on “Optical ASON or Electrical ASON!”

  1. Muhammad Yasir Shamm

    Thanks Faisal for an informative article. Can you please write an article on DWDM vs OTN (Optical and Electrical Sub layers and switching technologies use in both) and also Muxponder vs Transponder

  2. Mohammad Hamed Arezoomandan

    Dear Faisal

    I hope all is fine
    many thanks for amazing article
    Could you please give me information about FONST5000 Fiberhome and implementation of wson and ason in this equipment

      1. Mohammad Hamed Arezoomandan

        Dear Faisal
        Many thanks for your attention
        if possible please give me information about GMPLS and how the vendors used this protocol for switching

  3. Hi Faisal,
    I have a doubt in ROADM-Reconfigurable optical ADD/Drop Multiplexed.
    I have a ROADM Mux ,its connected to 3 different direction lambda(different colour,A,B,C).Assumption: Each lambda capacity 10G.’A’ lambda carrying 10G full traffic, B & C lambda carrying 5G traffic compared to less traffic in A. Now A lambda carrying 10G got failure, So now ODU traffic will be switch over to rest of the B & C lambda(different colour).

    In this scenario, Is protocol decide to switch the Shared traffic to different Colour Lamba? And also this switching will be happened automatically or manually?
    Kindly advice.

  4. Hi Faisal,
    Thanks for your post..
    Could you please explain importance or need of using GMPLS protocol? what does it do?What are the parameter concept based Both Lambda / ODU switching happening?

  5. I am having 40 channel 100G OTN with 6 directions. Its having UXU2 (Cross connect card) which connects service cards to Transponder. This OTN also have WSS8 card. We r using 2 channels 39,40 in each direction. I want to know in case of fiber cut in 1 direction how will the WSS switch the traffic to other direction as we r using same 39 and 40 channel in each direstion.

      1. Thanks for ur prompt reply. I am new to OTN. We r using Fiberhome FONST 5000. I want to ask if we r using electrical ASON, then why did the pair of WSS8 and ODU8 used in the WDM shelves. The WSS is interconnected to all other 5 direction WDM’s WSS. Also, does the 4 UXU2 cards will be able to ASON the 40x100G data in case of fiber cuts?

        1. Hello Abhay,

          As far as the FONST 5000 concern it’s only support DWDM, and its upgrades version U20 is having OTN feature, now answer to your question, they are using a pair of WSS and ODU in every direction to make it fully functional ROADM configuration, also you must be using 1 or 2 pair for local add drop as well. So you can understand like that directions or path calculation can be done by WDM cards and switching and restoration is being carried out by UXU2.

          1. Hi Vishal
            We are using 2 Lambdas in each direction and all the lambdas terminates at U20 rack using 1LN4 transponder card.
            Is this ROADM dynamically reconfigurable or manual configuration is required, if more lambdas were used and switched using WSS?

    1. Mohammad Hamed Arezoomandan

      Dear ABHAY

      I hope all is fine
      could you please give me information about cross connection of U20/U60 product of Fiberhome ?

  6. Good Day

    Please advise if Optical ASON is exactly the same as WSON as there is no clarity. Can you explain why you state that they are the same? thanks

    1. Thanks Mary,

      The right name should be WSON. As WSON is a standard but optical ASON is just an industry term. But the industry is using the word interchangeably. Yes they are same but a word of caution. Sometimes the vendor would use the word optical ASON to mean that they support optical control plane without satisfying the detailed framework of WSON. For example WSON would mean that the equipment can switch based on optical impairments also in addition to fiber cut. Some vendors dont support switching on optical impairments. therefore they prefer to use the word optical ASON instead of WSON as then they just support a subset feature of WSON but not full WSON.

  7. Ashish Batajoo

    Hello Faisal,
    what about electrical ason for 100ge? is it better than optical ason for long hub for 100g lambda system? or same as optical ason requiring regenerator if optical parameters not optimal.
    as multiple 10g to different direction are regenerator as each add\drop nodes.

    br,
    ashish

      1. Thanks Faisal for your reply. Does optical ason can gurantee under 50ms protection with 1+1+r and 1+1 protection.

        1. You will use ASON mainly for restoration and not protection. Any 1+1 protection will guarantee 50 ms. 1+1+r will guarantee 50 ms even for more than 1 fiber cut.

          1. Dear Faisal:
            we can use optical ASON for working + Protection if in case we use transponder level protection.
            correct me if i am wrong

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