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Dell, BT alchemists turn bog-standard HW/SW to flexible, open networks

Playing the disaggregation game

Analysis Dell EMC is supplying network switches to a proof-of-concept research project at BT Labs in Adastral Park, Suffolk.

The concept to prove is that programmable disaggregated open-switching hardware can create more adaptable and flexible networks than ones using proprietary integrated hardware and software network switches.

Dell EMC spokesperson David Graves said: "In general, I would say having the opportunity to work with an industry leader such as BT helps us gain insight and feeds into our future Open Networking product roadmap planning."

The commercial off-the-shelf (COTS) switching hardware, using merchant silicon and not proprietary ASICs, is loaded with open-source or commercially available network operating system (NOS) software. BT is using a combination of Dell EMC disaggregated switches, principally Dell's S-series for now, and such software to test the delivery of dynamic network services across fixed-line and wireless networks, saying it is applying virtualised server-like principles to switching.

It will check out the performance, economics and programmability of this virtualized hardware approach and compare it to the use of traditional integrated switching hardware and software, meaning Cisco and Juniperland.

Juniper is actually an integrated network switch supplier that is disaggregating by developing a Linux-based Junos software variant separate from its Junos NOS and switching hardware. It can see a whole raft of competing suppliers heading towards the SDN/disaggregated switch area, such as Ansible, Big Switch, Cumulus, Dell, Mellanox, Pluribus and others, and doesn't want to miss this tide.

Juniper says this disaggregated software allows users to manage the data centre switch just like a server, and run third-party applications, tools, and virtualized services in a virtual machine (VM), or as containers directly on the switch. The switch is basically a COTS server with network ports.

Its QFX5200 switch adds high-performance switching to a quad-core CPU server, offering speeds from 10GbitE to 100GbitE and supporting 25GbitE and 50GbitE Ethernet standards.

The idea is that customers can buy network-switching hardware from any vendor they choose and then run network-switching software in it from any vendor they choose; similar to buying x86 servers today.

This is different from SDN – software-defined networking – but connected. SDN is about the controlling the management plane of a network, and about network automation and analytics. It talks to network devices, like switches.

An SDN can use disaggregated switches and, if they, as they should, have an API, make instant changes down at the switch level.

It is also different from NFV – network functions virtualisation – where, as we see it, services such as load balancing, intrusion prevention and firewalling are virtualized into an abstraction layer separate from the underlying hardware. An SDN system can, will, and should talk to the NFV, but the NFV won't necessarily talk to switches unless their hardware/software combination carries out some underlying NFV function.

A disaggregated switch could, by running some network application software, easily run some NFV functionality and thus be simultaneously part of an SDN's management domain and the NFV domain.

Graves said: "VMware NSX software is a Network Virtualization Overlay. NSX runs on servers, not on switches. Though not in scope for this exercise, NSX could be viewed as a complement."

BT and Dell say the disaggregated switches in their project can be managed using the NETCONF protocol and YANG models, making the entire system inherently programmable. A set of switches can be operated in concert to spin up new network services or make dynamic configuration changes.

The two companies are evaluating use cases for this, such as the instant activation of Ethernet circuits from a third party (such as an enterprise), and the ability of the system to deliver real-time network operational data to interested parties. The network's switching bandwidth could also be dynamically altered for certain classes of users or traffic according to the passage of time. This is called bandwidth calendaring.

Obvious examples could be providing network bandwidth for corporate accounting functions at the end of every quarter. But that seems fairly lame when contrasted with the desirability of a feedback loop involving network performance monitoring detecting network availability issues at some point in the network and automatically reconfiguring it, programatically, to resolve the situation in real time.

BT would say, we think, as would Dell and EMC, that the potential of both SDN and NFV can be better realised with disaggregated switches than with what we might call monolithic integrated switches using proprietary hardware and software.

We would say that the monolithic switch suppliers like Cisco will have to face superior SDN and NFV functionality based on using disaggregated switches with better performance, flexibility and lower costs, before its stranglehold on the network industry can be prised open. ®

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