The problem: Unpredictable bandwidth demands and traffic patterns!
Bandwidth peaks can exceed the mean by 10x, 20x or more – and can last anywhere from tens of minutes to several hours or even longer.
Can we solve the problems without a new paradigm?
Contracting for a private line or for a committed information rate (CIR) sized to accommodate such peaks is at best not cost efficient and for some Enterprises just prohibitively expensive.
Trying to dynamically adapt to the demand is also not possible, as contracts would need to be re-negotiated, planning would need to be redone and network re-configurations would need to take place carefully, to avoid service disruption and therefore unhappy customers.
The solution is dynamic services! Many verticals, including manufacturing, media and entertainment find dynamic services very interesting and would be willing to invest to achieve this flexibility. Is there any way to do it? Enter SDN.
Using SDN to make Wireless Transmission Flexible
OpenFlow-based Wireless Transmission SDN will enable carriers to offer bandwidth on demand (BWoD) services that will allow their customers to dynamically establish and subsequently resize connectivity between their sites as necessary—and to pay only for the network resources that they actually use.
How Customers are Connected
Enterprise connectivity services require access from each customer site to a dedicated port at the edge
of the wireless transmission network operated by the service carrier. This can be done using Point to Multi Point (PtMP) network terminals at customer premises, which are connected to PtMP Hubs or base stations and are then backhauled over Point to Point Wireless Radio Links.
In this case, the user network interface (UNI) is typically Ethernet (e.g., 10/100GbE). Forwarding from the UNI may be physical port-based or logical sub-port–based, in which case customer traffic is mapped to its respective BWoD “switched virtual leased line” (SVLL) by matching ingress VLAN IDs.
Inter-site switching of the SVLL will be radio-based, as displayed in the diagram.
The Role of a Broker/ Scheduler Application
On-demand connections are established by the customer interacting with a bandwidth broker/scheduler application hosted on an SDN controller.
Requested connection parameters are communicated through a portal or over a northbound API (NBI).
- The portal realizes a self-service approach, where the customer orders bandwidth, i.e. it is not dynamic but still it is flexible!
- The northbound API allows operations users, customer clients, and applications to request SDN communications services directly from the Control Layer.
The broker/scheduler application first validates the request against the customer’s contracted policy (e.g., endpoints or maximum aggregate bandwidth) and then invokes the path computation element (PCE) to determine whether a viable path exists.
If so, it proceeds to instantiate the connection—either immediately or when scheduled—via the SDN controller.
The SDN controller again uses the path computation element (PCE) to identify the best path and issues OpenFlow commands to the NEs to establish the bi-directional connection, including the mapping from client port to connection origination point, the hop-by-hop intermediate connections, and the connection termination point to client port de-mapping.
The key here is the resources of released or decremented connections to become immediately available for other connections.
Connection Parameters Required
Connection parameters may include:
- source and destination UNIs,
- maximum latency,
- protection tier (e.g., unprotected, 1+1), and
- sub-port mapping identifiers (e.g., VLAN ID), if applicable.
In addition, the connection request may be for immediate instantiation or a specified scheduled time in the future, and for an indefinite or specified duration.
SDN–enabled bandwidth on demand provides when realized on Wireless Tranmsissin Networks used for Enterprise Connectivity will benefit end customers and network operators alike.
End customers will become able to receive high bit-rate, deterministic capacity on a temporary basis when and where they need it, without the cost burden of over-provisioned private lines with long-term contracts.
Priced intelligently, the network operator increases overall revenues by increasing their addressable market to those who can’t afford such contracts. At the same time, the operator increases return on assets by selling capacity several times over per month and for higher value per time unit than a flat monthly fee yields.
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