SD-WAN is a new approach to building WAN infrastructures that is being adopted by many enterprises and making its way into the portfolio of many Telcos. SD-WAN today offers:
- Provisioning agility through Zero Touch Provisioning
- Central management and application performance monitoring
- Application aware routing to choose the most appropriate WAN service for the application
- Service chaining capabilities allowing advanced functions to be strategically placed in the network
While SD-WAN delivers great benefits and is supported by many solutions from both established and new networking players, there are still a lot of improvements to be made. In my previous blog about benefits of SD-WAN, I highlighted some functional improvements.
In this blog I want to touch on something that will become important over time as we rely more on SD-WAN and need to interconnect and integrate different SD-WAN solutions: standardisation."As SD-WAN is gaining more and more attention from Service Providers who are seeing their MPLS revenue fade and are looking to develop and deliver new services, the need for standardisation is increasing."
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While almost all SD-WAN solutions support various routing, secure tunneling standards and management standards such as SNMP and REST APIs to integrate into existing networks (Brownfields), none support a standard that allows you to join two different SD-WAN solutions into a single SD-WAN network or manage them as if they were one. In the traditional routed world using different products (Juniper Networks, Arista, Cisco) was not a big issue as long as you had stuck to open routing standards such as OSPF and BGP and hadn’t been lured into using proprietary standards such as EIGRP. Managing these routers through the CLI was also a standard of a sort, albeit a very basic one.
Understanding the Metro Ethernet Forum (MEF)
As SD-WAN is gaining more and more attention from service providers who are seeing their MPLS revenue fade and are looking to develop and deliver new services, the need for standardisation is increasing. The Metro Ethernet Forum (MEF) was, as its name suggests, founded to enable Ethernet-based carrier services. The MEF defined a framework for how carriers should build point-to-point Ethernet Virtual Circuits (E-lines) as well as multi-point Circuits (E-LAN). The framework includes UNI, NNI, ENNI definitions as well as guidelines for OAM integration.
With most of the work in the Carrier Ethernet space done, the MEF is now focusing on SD-WAN. At the SD-WAN summit in Paris in September, the MEF announced plans to work on SD-WAN based services frameworks. The MEF will focus on the following activities;
- Create an industry-wide accepted definition of what an SD-WAN service is
- Define certification of SD-WAN solutions
- Data model interpretations of SD-WAN specifications
- Promoting adoption of LSO (Lifecycle Service Orchestration) Presto APIs in SD-WAN controller solutions
- Multi-vendor interoperability using LSO
On October 30th the MEF released the first draft of the LSO Sonata interface specification which creates an interface for provisioning services that span multiple carriers. LSO Sonata is essentially an East-West interface. The MEF also released the first draft of the SD-WAN service definition. The LSO Cantata interface defines how the services can be ordered thus enabling automated ordering processes.
LSO Legato and Presto are still being worked on. Presto will be the interface for the provisioning of SD-WAN services for specific SD-WAN solutions where Legato sits higher and allows a standard approach to defining services, creating service catalogues, orders and inventory.
Easing automation for provisioning SD-WAN services
The aim of these initiatives is to make it easier to automate the provisioning of SD-WAN services. Creating an integrated end-to-end SD-WAN service using multiple SD-WAN solutions is still a long way out. As there are no plans to standardise the SD-WAN control and data planes, we will need to rely on SD-WAN gateways to provide connectivity between different solutions and domains. The LSO framework will allow for the creation of a single provisioning interface that automates cross-domain provisioning (Cantata), and reporting and alerting (Allegro) making the disparate solutions appear integrated.
The use of SD-WAN gateways will become increasingly important as different SD-WANs will need to interconnect, either because of scaling, transition to another SD-WAN solution or the integration of acquired/merged companies that have implemented different solutions.
The fact that an organisation with a track record in this space has taken the lead in defining the framework is an endorsement of the future of SD-WAN, as is the fact that Gartner last week released its WAN-edge solutions report which analyses key offerings in the SD-WAN market. If you have or can get access to this report I recommend it as a good read to get a better understanding of the SD-WAN landscape.
Jan-Willem Keinke - 9 November 2018
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