B'com Overhauls Network Switches

　　Broadcom announced a new generation of its mainstream Ethernet switches, adding packet processing features and lowering costs at a time of rising competition. When the Trident 3 ships next year it will power systems with as many as 32 100 Gbit/second Ethernet ports that cost as little as $3,000 and consume less than 400W.

　　The news comes amid a barrage of announcements from competitors entering the networking market where Broadcom has held more than a 90 percent market share. An analyst for the Linley Group said the news supports his forecast that prices of Ethernet switch chips could drop from more than $60 per 100G port last year to about $36/port in 2020.

　　Trident 3 is a family of five 16nm chips with ports supporting 1-100 Gbit/s Ethernet. They range from a 200 Gbit/s aggregate chip for campus Wi-Fi access points to 3.2 Tbit/s components for data center top-of-rack switches and aggregation networks

　　Broadcom gathered support for Trident 3 from a broad range of OEMs, unbranded system suppliers and third-party software developers. They included Accton, Arista, Big Switch, Cumulus, Dell, Delta Networks, Extreme Networks, IP Infusion and Quanta.

　　The Trident line is the heart of Broadcom’s switch business with more than 100 million installed ports. Separate Tomahawk and Jericho lines aim to deliver maximum bandwidth and fan-out capabilities, respectively to the world’s largest data centers and service providers.

　　Broadcom held a whopping 94.5 percent share of the $687 million market for merchant 10–40-Gbit/second Ethernet switch chips in 2015, according to the Linley Group.  Cavium, Marvell and startup Nephos have chips competing with Trident.

　　Cavium has won sockets at Arista and Brocade for its 28nm XPliant chip and reaped “meaningful revenue last year,” said Bob Wheeler, principal networking analyst at the Linley Group. Marvell’s 28nm Bobcat 3 chip with 25GE ports is sampling, but offers lower performance than Trident 3.

　　Nephos spun out of Taiwan’s Mediatek with 1 to 3.2 Tbit/s switch chips to rival Trident. It will use TSMC’s InFO packaging to create a 6.4 Tbit/s version to compete with Broadcom’s Tomahawk II.

　　It’s too early to tell whether the broad set of products announced in March and based on one RTL design will gain traction, but they are not highly programmable, Wheeler said. The startup claims its users include a data center in China and a division of Taiwan’s second largest company.

　　At least two other startups—Barefoot and Innovium—are mainly targeting Broadcom’s high-end Tomahawk chip. Innovium announced its 12.8 Tbit/s TeraLynx switch in March and a $38.3 million Series C round that brought its total funding to $90 million. It expects to sample in the fall and won early support from a networking executive at LinkedIn.

　　Barefoot debuted a year ago, backed by some of the early pioneers of the move to software-defined networks. It helped create the open source P4 language for networking and its chips recently got attention from AT&T as well as China’s three largest data center operators.

　　In the face of the rising competition, “Broadcom is trying to get the message out it will be competitive on price,” said Wheeler.

　　It also made a point about its backward compatibility with the Trident 2 and support for regression testing. “That’s a powerful part of being an incumbent versus people launching a first-gen platform,” he added.

　　Overall, Trident 3 aims to offer new programming capabilities with deterministic performance at a new low in cost and power. “That’s big,” said Wheeler.

　　The two largest Trident 3 parts are already sampling, including the top-end member that ships in a 55mm2 package and packs 128 25G serdes. The chips include a 32 Mbyte buffer, twice the memory of the prior generation, in part to handle new programming capabilities.

　　A huge cry for easier-to-manage networks has risen with the growing size and complexity of data center and service provider networks over the last several years. Web giants such as Google have pioneered techniques to run more networking functions on banks of x86 servers, and telcos have hammered out specs for so-called Network Function Virtualization. Still, programming network switches remains something of a high art.

　　One of the biggest advances with Trident 3 is a broad set of programmable functions it supports. Broadcom uses a scripting language that’s part of a unified developers kit it provides supporting Trident, Tomahawk and Jericho chips. However, customers can also use standard software images Broadcom creates with the scripts.

　　“Use of images is still the dominant model, it’s not common for customers to expend R&D resources to focus on programming switch features,” said Rochan Sankar, a director of product marketing for network switches at Broadcom.

　　Trident 3 chips can be managed using open protocols such as OpenFlow or the P4 language. But for more granular control, users need to tap into Broadcom’s SDK and APIs.

　　Despite the complexity, there’s value in using the tools given the deterministic packet-programming pipeline Broadcom built into Trident 3. They make the chip look like a combination of a switch with a built-in network processor.

　　The pipeline includes a variety of programmable and configurable packet parsers, lookup tables, logic blocks and packet editors. Broadcom won’t reveal details of the underlying hardware such as the size of its match/action arrays, however it said it can handle more than 70 types of lookups useful in multilayer Ethernet switching.

　　The hardware supports a variety of virtualization, telemetry and load balancing capabilities that can be executed deterministically and in parallel. For example, it can process multiple lookups in parallel using virtual databases of different types and sizes.

　　In a sign of its usefulness, after the hardware design was frozen, Broadcom engineers were able to add support for in-band telemetry. The feature has become increasingly popular and is the subject of a draft IETF standard.

　　Trident 3 also supports a growing laundry list of network overlays emerging in the industry. “I think we’re at the outset of the journey [in network programming where] the requirements are starting to sub-segment…we support a large and diverse set of use cases,” said Sankar of Broadcom.

　　“It’s a little bit of a different animal from the programmable switches that came before,” said Wheeler.

　　Radical approaches to network programming such as Barefoot’s Tofino chip aim to be protocol agnostic engines. But that was not Broadcom’s approach, Wheeler noted.

　　“There’s still an assumption with Trident 3 its Ethernet switching and IP forwarding although they support alternative forwarding, too,” he said.

　　So far, no vendors are offering third-party tools for network programming. The P4 language Barefoot supports is “somewhat more open” than the Trident 3 tools, but Broadcom says P4 doesn’t support many of the functions its tools enable.

　　Barefoot claims what’s important is an ability to program the forwarding plane of the switch, something its Tofino chip enables using P4.