While software-defined networking is only just starting to gain significant traction within enterprise networks,...
it has transformed network service providers. They are bringing SDN technology to the enterprise edge now, in the form of virtualized customer premises equipment, or vCPE.
In the past, a provider delivering a set of network services would use specialized hardware to deliver the services. This hardware was most often a branch router, and it sometimes included one or more separate firewalls, a distributed denial-of-service defense device or WAN optimizer -- all in the branch.
Now, the goal is to have generic hardware at the branch and have it run some or all of the software needed to provide all of the desired services.
Shifting the burden from hardware development to software development brings providers unprecedented flexibility and agility in addressing market needs. It also simplifies deployments if a single box -- a so-called universal CPE, or uCPE -- can run the branch end of any service needed.
VNFs: Making services more modular
The traditional software-only delivery of a network function has focused on virtual appliances, which tend to fully replicate the functions of a hardware appliance in a single unit. The network functions virtualization approach separates the appliance into smaller function parcels -- virtual network functions (VNFs) that cooperate to deliver network functionality.
A service provider can dynamically push VNFs down to the CPE platform to run on the customer premises, run the VNFs in server resources on the provider side of the edge or even run them in their own core -- wherever makes the most sense for that service and that customer. Firewall functionality, for example, can often be best delivered on the provider side of a link -- why deliver a packet that will be thrown away as soon as it hits the CPE? But compression services are best delivered on the customer side to maximize their effect.
Changing the WAN
Virtualization, uCPE and vCPE are creating new opportunities for both providers and customers to adopt new services, try new platforms and transform their IT infrastructures. Enterprises are keenly interested in software-defined WAN right now, and many providers use a vCPE model to deliver SD-WAN.
Some providers adopt a fully edge-hosted model, in which a uCPE box hosts a complete SD-WAN package -- one that could run on dedicated hardware. Others deploy a hybrid edge or cloud model, where the SD-WAN depends -- to some extent -- on services delivered from the provider's cloud. Still, others have a fully cloud-hosted model, like network-as-a-service providers delivering SD-WAN as a feature set service.
Whichever model a service provider uses, the number and breadth of vCPE deployments are exploding in the wake of providers' internal SDN transitions and with the strength of interest in SD-WAN.
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