SlickStack

Blog

  • The Marriage of IP with OTN/DWDM !

    The Marriage of IP with OTN/DWDM !

    When revenue per bit starts falling and cost per bit starts increasing, it’s time to think about alternative strategies to expand Transmission/IP network.

    As IP is predominant traffic in Transmission networks, therefore any expansion strategy on Transmission should be driven by IP demands. Indeed, both IP and Transmission departments need to work for a joint and synergetic expansion strategy, in this regard.

    Hence, I intend to share with you some insights and tips that will enable you to plan the expansion of IP and Transmission network in a holistic and synergetic way. If you stay till the end, you will see how IP can live with lower layers of Transmission (DWDM, OTN, SDH, and L2) through a successful marriage.

    Whether you belong to IP department (responsible for the IP/MPLS domain) or Transmission department (responsible to run SDH, DWDM, OTN and most recently Ethernet), there is some food for thought for you in this article. More specifically, I will show you how to put your traffic on the right layer that will reduce the TCO (Total Cost of Ownership) of your Core network.

    So let’s see where is the problem? (more…)

  • Are you asking these Questions from potential MPLS-TP Vendors?

    Are you asking these Questions from potential MPLS-TP Vendors?

    Are you a transport or a mobile backhaul operator with a goal to deploy easy to operate  Ethernet transport  solution based on MPLS-TP?

    Do you know that you may run into potential surprises if you treat MPLS-TP as any other technology you evaluate.  In fact, not all systems are equal, and this is particularly true about MPLS-TP gear.

    MPLS-TP hadn’t  had a smooth sailing when it comes to standards. For long, the industry was divided between two camps of vendors supporting two different MPLS-TP OAM standards, with no consensus between them. Finally, the industry did reach an agreement on OAM standards, but on TWO parallel standards instead of ONE.

    Furthermore, MPLS-TP vendors, broadly, come from two different backgrounds: Some come from a rich experience of the IP domain whereas others are more experienced with the transport technologies. This demarcation is clearly reflected in the features they offer.

    Therefore, there is enough in the vendors’ offerings to confuse an operator who plans to buy MPLS-TP equipment.

    Hopefully, this article will guide you with what to look for in MPLS-TP offerings, and help you ask right questions from a potential MPLS-TP vendor to avoid some come pitfalls. This comes from my experience of working with multiple MPLS-TP vendors. Therefore I am sharing this with a hope to benefit larger audience. (more…)

  • What your DWDM vendor did not tell you about latency for your Data Center Interconnect

    What your DWDM vendor did not tell you about latency for your Data Center Interconnect

     

    DWDM latencyAre you concerned about  latency in your data center links running  over optical network ?

    Or, are you planning for Data Center Interconnectivity in near future and want to know  the impact of delays involved. The read on, for some useful tips to know your options.

    Chances are, you are already using DWDM to connect data centers but there are few things that you should be aware of as an operator regarding the sources of delays in your optical links in order to either mitigate them or at least know how to properly dimension your network for delay. As they say , NOT all DWDM systems are equal when it comes to latency in them so it would help to know what are the choices available when comparing DWDM systems.

    In this era of Cloud networks, it would be naive to ignore the impact of delay in optical networks that run clouds. Impact of delay for financial markets that do High Frequency Transactions ( HFT) can be considerable and far reaching; fraction of millisecond can impact revenue and as per one estimate,these fractional delays can contribute to difference of revenues over the year as high as 100 Million USD.

    Lets see, what are these factors that cause delay and what measures can be taken to deal with them. Perhaps your DWDM vendor did not tell them to you, yet. (more…)

  • What is it that Operators miss on 100G Optics ?

    What is it that Operators miss on 100G Optics ?

    What  is it that  operators miss on 100G optics/transponders ?

    Is it reach, cost or availability  ?

    In fact none of them.Telecom Lighthouse

    We have Coherent optics that can span thousands of kilometers, and we have prices getting competitive reasonably, so what is it that  operators would still want on 100g optics. Read further.

    What operators want, is an efficient  solution for metro applications; more specifically, pluggable type of “Coherent transceiver” for the network( line) side of DWDM . The bulky and power-hungry coherent transceiver today is suitable for long haul applications but not for  metro applications. Deploying them for metro applications ( lets say 100 KM or even more) is  an overkill for price, space and power.

    Let me show you where is the gap today: (more…)

  • Which Queuing Mechanism is best for QoS?

    When it comes to QoS in Packet Transport environment, Queuing mechanisms insides switches and routers  hold key importance.There are a variety of methods used by manufacturers.
    So which Queuing mechanism is best for QoS for routers and switches. There is no clear answer to that because every queuing mechanism has certain Pros and Cons. I have summarized main queuing mechanisms and reflected a comparison of them in the following table. (more…)

  • Three things, Operators should know about combining Protection on IP/MPLS and Optical Layers.

     

    If  an Operator decides to deploy Multi-layer protection using both IP/MPLS and Optical domain, he faces a number of challenges: IP/MPLS and Optical control planes work separately in transport networks; they are, usually, disjoint and do not communicate with each other. IP/MPLS circuits are provisioned as one of the services for optical layer with no co-ordination between them. While the “disjoint” protection strategy may work.but it is NOT a very efficient way in the long run.

    Operators who chooses to adopt a pure IP+ Optical protection/restoration model (in comparison to other models that include OTN as intermediate layer) should consider the following three things:

    1. Tight Integration between IP/MPLS and Optical Control Plane: For the model to bring down CAPEX and resource efficiency, there should be a tight integration between the NMS (Network Management System) of IP/MPLS and that of Optical domain, resulting in seamless integration. When fiber cut happens, how different layers would react and in which order, shall follow a proper sequence.  IP/MPLS should  know the optical resources and routes through GMPLS NNI+ interface enabling it to make better routing decisions.The signaling between the two layers can better optimize resources and informed decisions on when and which protection should come into play, once fiber cut happens.
    2. IPoDWDM. If operators choose a pure IP and Optical path(with no OTN switching layer) the IPoDWDM  option makes sense. This will, further, bring down transponders’ cost. Otherwise, adding an overlay of back to back ports (grey ports of router to transponder on DWDM) can make the cost of lambda high.
    3. Organizational Structure: Last but not the least, operator must look into its own organizational structure. Operator should align its own organizational structure with its planned  technological integration. Most importantly, if transport and IP departments are separate entitites, it is time to look closely at reorganization . As “Transport” and “IP” merge as technology, organisational structure should follow suit. Therefore, one department that plans and operates both IP and Transport  makes sense in such cases. The model of having combined network protection/restoration strategy only works if there is a tight integration between the structure, processes, operations and management of both transport and IP groups. This has been found to have worked successfully in those organisations where there is one group that is responsible for the transport and IP part. Operators should align their department strategies keeping in view  these changes in networks today.

     

     

     

     

     

     

     

     

  • IP/MPLS made easy for backhaul

    Today, I spent the day at Tellabs PoC (Proof of Concept) showcasing their DWDM and Mobile Backhaul portfolio. Tellabs had put up an impressive collection of equipment showing an array of portfolio including 7100 Nano, 7300 Carrier Ethernet portfolio and 8600 series for Mobile backhaul. I was particularly interested to see their backhaul equipment in action. Tellabs is one of those that advocate IP/MPLS for Mobile backhaul. They proudly boast of making IP/MPLS quite easy to work with for backhaul people. As a technology, I do consider MPLS to be quite complex for transport people to handle in backhaul. (more…)

  • Difference between SDN and NFV

    There are some confusions surrounding the differences between SDN and NFV. Both terms relate to virtualization of network; both are hot topics these days. Sometimes, one concept is mixed with the other.

    SDN stands for Software Defined Network. It is based on  two pillars.

    1. Separation of data and control plane and centralization of control plane.
    2. Programming network with open interfaces.

    SDN concepts came into being while researchers were frustrated with changing   software in network elements every time they wanted to try something new to study behavior in network. They thought, why not program the network elements and manage them from central place. The language that brings this programmability to network is called “Open flow”. (more…)

  • Does P-OTS 2.0 address operators’ needs?

    Research firm, Heavy Reading, defines “P-OTS as a platform that combines SONET/SDH, connection-oriented Ethernet, DWDM and, depending on where the platform is used within the network, also optical transport network (OTN) switching and reconfigurable optical add-drop multiplexers (ROADMs)”

    As per Heavy reading, there is a growing trend now, with more and more operators asking about IP/MPLS capabilities in P-OTS platform. Transport groups inside operators have expressed their interest to add layer 3 functionality to P-OTS platforms. Operators favor integrating L0 to L3 in P-OTS platform so that one platform can meet all their needs. This new requirement is addressed in P-OTS 2.0. According to Heavy Reading, there are four differentiating features of P-OTS 2.0 compared to legacy P-OTS.

    1. There is change of focus from TDM to packet functions.
    2. Pure packet implementation of P-OTS is ramping up.
    3. 100G is seeing more applications in metro area
    4. Switched OTN has entered Metro area, removing the need of SDH fabric in new network elements.

    Looking at what is present in the market today; the P-OTS platforms leave a lot to be desired. It would be hard to find a product optimized for all layers. Legacy P-OTS platforms are optimized for certain applications but not for all. Depending on where the vendor is coming from, some P-OTS platforms are optimized for TDM applications but not for ethernet applications. Some are strong in DWDM but not in packet and TDM. Some vendors position to carry Ethernet over OTN; still others vouch that carrying Ethernet in native form is better and keeping OTN as option on P-OTS platform. P-OTS, thus, has become more of a marketing term rather than the platform that can address all the needs, desired for such platforms.

    P-OTS 2.0, therefore, should be able to address all layers (layer 0 to 3) effectively and in optimized way. Operators would not like to have platforms (similar to P-OTS) that are geared and focused on few applications and leaving the others as just “supported on platform”. P-OTS platform shall be modular and platform based preferably supporting a family of platforms for applications from metro to core. Cards should be interchangeable between platforms. The platforms should support IP/MPLS but above all GMPLS across Layer-0 to Layer-3. Again it should be possible to run all layers independently or all layers run tightly together, seamlessly. The layers should communicate with one another, for example, for fault management. These are the needs of the operators today and vendors ought to rise to this occasion.

  • NaaS as step towards SDN

    API is the most powerful feature of SDN- the programmable network. It will open a world of opportunities in terms of flexibilities and features for both operators and app developers. The current networks are rigid and make operators “lock in” to vendors. SDN will help avoid this lock in by making a network a flexible platform which will respond as operators desire. This will reduce OPEX that comes because of manual provisioning of services and will help in bringing innovation because the operators may develop new applications easily and flexibly.

    SDN focuses on Network as a service or what is termed as “NaaS” in cloud computing. With Naas operators will have control over bandwidth, routing and QoS of their data. They will be able to give differentiated services. With SDN, operators can leverage the existing NaaS initiatives and build up their SDN infrastructure from there. The knowledge and skills gained with NaaS today will be and prove very useful to develop SDN ecosystem of apps. The experience of these operators can help the new comers into SDN to learn from them.