(Photo: The hand of Nathan Brockwood, analyst with Insight 64, tries to feel the heat coming off the Broadcom Tomahawk chip at a demo station in Broadcom’s San Jose, Calif., labs. He was thwarted; a strong fan was blowing cold air over the chip.)
That could open the door for Tomahawk, as the new chip is called, to handle arbitrary, experimental protocols including OpenFlow 2.0, whatever that turns out to be. But Broadcom is touting the feature more as a scalability aid, as it means that one switch could handle the needs of multiple data-center tenants doing many types of networking.
Tomahawk, being announced today, is not a replacement for Broadcom’s Trident II, which is the favored off-the-shelf chip in the current generation of high-end Ethernet switches. Tomahawk aims for an even higher-end market of hyperscale data centers and anything else requiring the highest port counts and lowest latency available.
The chip is hot off the presses, with the first samples in customers’ hands. At a small gathering for media and analysts Tuesday evening, Broadcom showed the chip running a 100-Gb/s signal through each of its 32 ports.
Programmable, Like Xpliant
That kind of scale is Tomahawk’s hallmark, and it matches the rumors that the chip would boast switching capacity of 3.2 Tb/s on paper. Not surprisingly, Tomahawk is also primed to support the 25-Gb/s Ethernet standard that Broadcom helped push so aggressively and the potential 50-Gb/s standard that’s still under debate.
Tomahawk also includes two features that could be considered nods to software-defined networking (SDN).
First, FleXGS provides the kind of programmability that Cavium introduced last week with the XPliant Packet Architecture. Namely, it’s the ability to alter the way the switch handles packets — letting it check non-standard parts of the packet header or having it examine packets in a way that’s different from the norm.
This means the chip could still be used even if new protocols arise. That’s a possibility if any form of OpenFlow 2.0 ever starts taking off, for instance — something that startup Barefoot Networks has reportedly been focused on.
Broadcom isn’t characterizing FleXGS so radically, though. Officials stressed the chip’s ability to change personalities, so that it could be an MPLS switch for one set of customers and an OpenFlow switch for another set, for instance.
Certain policies could also now be programmed as switching rules inside the chip, rather than being enforced by the control plane or by a policy controller. It’s a way for policy to be applied at large scale, Broadcom officials said.
Cavium is joining the Ethernet switching market for the first time through the acquisition of Xpliant, a startup that was working on a programmable switch chip. It’s not clear how Xpliant’s programmability compares with Broadcom’s, both in terms of capabilities and in ease of programming.
SDN Feedback Loop
Tomahawk’s other SDN feature is Broadview, a set of visibility and analytics capabilities that would let a switch relay traffic information to the control plane. This would drive the automated feedback loop that’s a key selling point for SDN. For instance, the control plane could be notified about congestion building at a certain node and could start redirecting traffic accordingly.
Broadview also includes a troubleshooting feature that lets operators inject a packet into the network to discern what decisions the switches are making.
One around Tomahawk is the same one that bedeviled Broadcom’s flagship Trident II chip — when does it get into volume production? Trident II was late getting there, meaning not all customers could get the volumes they wanted. Broadcom didn’t offer a timeframe but pointed out that a year’s wait between sampling and production wouldn’t be unusual.
As for the customers who’ve got Tomahawk in-hand — the list includes “top cloud customers and OEMs,” officials said at Tuesday’s event. In other words, Tomahawk is being used not only by the switch vendors who are Broadcom’s usual customers, but by some of the hyperscale data center owners themselves.
Broadcom also showed a list of the partners who’ve given input to the chip’s design, and Cisco and Juniper were both on it. Broadcom didn’t elaborate. Both companies have been adamant about the importance of developing their own switching and routing ASICs for high-end gear, but both have also copped to using merchant chips in recent designs — Cisco in Nexus 9000 line cards, Juniper in QFabric.