Cumulus Networks unveils 'Cisco killer'

Startup's Debian-based Linux distribution for commodity switching hardware aims to upend networking's status quo

After three years under the radar, secretive Cumulus Networks has finally emerged from stealth mode. Founded by ex-Cisco and ex-EMC VMware engineers looking to shake up switched networking by leveraging Linux and commodity network hardware, the small Silicon Valley startup turns out to be a software company. Cumulus will sell only software -- namely, Cumulus Linux -- and support. The hardware can come from any vendor you like, and Cumulus has a list of compatible switches to choose from.

These aren't expensive, proprietary switches like those you'd buy from Cisco, but switches based on merchant silicon from original design manufacturers (ODMs) such as Quanta and Accton. However, you might find that these switches bear a striking resemblance to switches from major market vendors. This is because ODMs manufacture those switches that are then rebranded and loaded with software.

To deploy Cumulus switches, you purchase a software license, buy your own switch from a hardware vendor, load the software, and start pushing packets. This effectively turns the networking model on its ear, because the model stretching back for decades is that the hardware and software comes from the same manufacturer, and loading a different operating system on a network device is as uncommon as loading any OS on any random PC is common.

Part of this disparity was the need for networking hardware and software to work together at scale, across multiple units, and at wire speed. The companies designing the hardware and the software had to tightly couple those elements together to achieve the speeds and density necessary to provide a solid and stable networking platform. As processing power and ASIC development has progressed through the years, however, that has become less of an issue, allowing the decoupling of hardware and software at the network level.

The upshot of all this? Cumulus boasts that with ODM hardware running Cumulus Linux, you can deploy 10G for the price of 1G. Initially, Cumulus supports a variety of 48-port 10G 1U switches and claims a cost of around $7,400 for the hardware and software license. That compares favorably to the cost of 48-port 1G switches with 10G uplinks from many manufacturers, depending on the software feature set.

Cumulus says its switches have been running in production at several places for the past six months. These deployments include a large IPv4-only implementation with more than 5,000 switches and a smaller buildout at DreamHost.

Cumulus Linux is a highly modified Debian distribution. Cumulus has developed drivers and associated bits to allow the Linux kernel to control such elements as bridging and routing tables and general networking tasks, but by controlling the dedicated switching hardware rather than handling the actual routing and switching tasks internally.  

Otherwise, the OS is standard Linux, which offers many management options, including Puppet and Chef integration, or essentially anything else you can run on Linux. This opens the door to integration with existing central management frameworks already in place in many infrastructures.

Being Linux, the switch drives like any other Debian system you've ever used. There is no special command-line interface or shell dedicated to switching, routing, and other network operations. There is no new language or syntax to learn. It's just Debian running a collection of open source tool sets and the Cumulus daemons.

When you log in, all the usual tools are there, or can be installed with apt-get. You log in to a Bash prompt, you can su to root, and you have free rein over every aspect of the OS itself. It's essentially like logging into a Linux server with 48 10G ports.

This means that all switching, routing, and firewall configurations are performed the same way as on a standard Linux server. You configure IP addresses using ifconfig, you configure bridging groups and VLAN tagging through /etc/network/interfaces, and you configure firewalling by writing iptables rules.

By default the OS uses Quagga to handle heavier-duty routing protocols, so you would handle that just as you would with any other Quagga installation. The key here is that there's a process that listens on the Linux Netlink layer for changes and modifications to the networking properties of the system, translates them, and passes them along to the underlying hardware. This is what allows the Linux layer to drive the switch, but not interfere with the speed of routing and switching operations.

Naturally, all of this is scriptable and remotely configurable as any other Linux system would be. Using shell scripts or Python scripts, you can automate processes like any other server. Except that it's not a server, but a 48-port 10G switch aimed at turning the networking world on its head. It's about time.

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