The next generation of networking is more complex and multi-functional compared to the networks of today. Networks are moving from “connectivity as a service” to “multi- service platform.
- SDN & NFV are complementary technologies
- NFV depends on SDN to deliver network features that enable it.
- Both use controller concepts for Operations and Administration (OAM).
- NFV offers two general types of services, network and user.
Comparing SDN & NFV
Software Defined Networking operates the forwarding layer in a network. There are many sub-technologies here such as overlay/encapsulated networking, controllers, APIs and applications that replace the previous generation of forwarding technologies. Networking could be performed directly in hardware using technology like EVPN/MPLS or using overlay like VXLAN/MPLSoGRE depending on market development over the next few years.
Network Functions Virtualization is focussed on network appliances that perform path control, protocol manipulation, logging/monitor/capture, content analysis, security control and similar functions. These functions are in use today as routers, firewalls, IDS/IPS, proxy caching, WAN acceleration, data centre and WAN load balancers. But also include services such as identity & authentication management (IAM) with AAA, data loss prevention, malware/virus inspection/detection, content.
Today, NFV services are most likely to be deployed using virtual appliances operating on a x86 hypervisor.
Functional Elements of SDN & NFV
If you read the previous section and found it confusing, you are not the only one. I am attempting to summarise complex concepts. The following diagram should provide more comprehensive view of how network functions break down.
There are four general areas I consider make up a complete NFV platform.
- A flow managed network can be programmed predictable and safely so that packet, flows and paths are able to integrate with mobile virtual appliances.
- SDN Applications and controller that can manage, monitor and analyse the overall network status and integrate with the NFV controller system.
- Network Services are basic network functions such as firewalls, traffic shapers. The key factor is that they operate on protocol flows between endpoints in the network.
- User Services that support network services, or provide additional network function. For example, AAA/IAM functions may support VPN devices for user management while security monitoring (ie capture/inspection) is a user service.
The next piece of NFV is how to provide services to a network conversation and is called “Service Chaining”.