A handful of open-source consortia, led by ONOS and the Open Networking Foundation, have teamed up to develop and launch a leaf-spine data center fabric using all open-source software running on white-box switches. The system also uses an app running on the clusterable ONOS SDN controller.
All of the software is available today for download. Broadcom-based switches from EdgeCore, which have been designed to work in this fabric, are also available for purchase.
At present, the ONOS fabric targets telcos and service providers. According to ONOS, telco companies are field-testing the fabric via the Central Office Re-architected as a Data Center (CORD) initiative, which leverages commodity components and open source software to help reduce costs and improve flexibility.
That said, it’s anticipated that enterprises will also find use cases and get involved in the project.
This system is a glorious mashup of a multitude of open-source projects and lots of moving parts, so let’s take it piece by piece, starting with the physical layer. Then we’ll look at the network OS and the fabric.
Get Physical
The physical layer is powered by Broadcom Trident II-based switches from EdgeCore, including the 40GbE 6712 and 10GbE 5710 and 5712 product lines.
The platform takes advantage of Broadcom’s OF-DPA (OpenFlow Data Plane Abstraction), which enables Broadcom silicon to be programmed via OpenFlow version 1.3.4.
“Going with OF-DPA gives us ability to program all flow tables and all port groups,” said Saurav Das, principal architect at the Open Networking Foundation, in an interview.
Note that this ONOS fabric requires, at present, a specific build of OF-DPA that is provided by ONOS. It also requires an OpenFlow agent to run on each switch. The ONOS fabric uses a modified Indigo agent. Indigo is an open-source project from Big Switch Networks.
The Network OS
The switches in this ONOS fabric must run Open Network Linux (ONL), a switch OS that came out of the Open Compute Project (OCP). The ONIE bootloader, also from OCP, comes pre-installed on the switches to enable the OS to be loaded onto the device.
The Fabric
The leaf-spine fabric relies on controllers that run the Atrium 16/A release. The fabric can support up to 16 racks of switches.
Traffic within a rack is L2 bridged Ethernet, with the switches programmed by the controller cluster. When traffic has to go from one physical rack to another, the fabric relies on segment-based routing that uses MPLS labels to ship packets across the fabric. The controller cluster manages label distribution.
Multiple controller instances can run in a cluster to ensure high availability, and physical switches are simultaneously connected to more than one controller instance.
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Dive In
The movement to bring open source software and open hardware to the networking market is in full swing, with a laundry list of projects being undertaken. Of course, that laundry list could hamper uptake by inundating network operators with a baffling array of choices.
This ONOS fabric effort aims to reduce some of the confusion by corralling the necessary pieces into a single project. But even this project comes with a long list of elements that need to be downloaded, installed, and assembled. This is by no means a plug-and-play undertaking.
And yet, this is likely a first step toward a more integrated offering In the meantime, if you’re interested in diving in, all the software related to the ONOS fabric can be found here.
