Brad, can you elaborate on Cisco’s Jawbreaker project? What exactly is it? Is it a response to Juniper’s Q-Fabric? Is it an attempt to rectify the inconsistencies in the differing purpose-built approaches of the N7K and N5K?

Why create a new architecture?

It seems like Cisco is really in trouble – creating a new architecture, abandoning its own silicon for merchant silicon; they seem to have missed the boat with regard to flat networks.

Here is an article worth commenting on:


For reasons that should be fairly obvious I can’t discuss in detail rumored Cisco R&D projects such as “Jawbreaker” in a public forum.

I did read the Network World article and found it suspiciously interesting how many presumptions were made about a Cisco R&D project, such as ship dates, architecture, motivations, etc. As far as I’m concerned, some of these assertions were just flat-out wrong.

Cisco, like any other tech company, is going to have R&D projects with cool sounding names. Some will survive and turn into real products (e.g. Cisco UCS), others will never see the light of day. It’s how any good tech company flushes out the good ideas from the bad.

You can also bet that Cisco is looking at ways to evolve the Nexus platform with dense and highly scalable 40G, 100G, and beyond. I think that’s a fairly obvious assumption to make. No? Just because a project may have a name like “Jawbreaker” doesn’t mean it’s not Nexus.

Merchant Silicon

Depending on the application, sometimes merchant silicon does the job well. Take for example the Nexus 3000. If your application just needs the lowest possible latency for say, high frequency trading, the merchant silicon available today does that well, really well. Therefore it makes sense for both Cisco and it’s customers to have timely access to these products at competitive prices, running industry proven and feature rich switch software (NX-OS), and backed by Cisco’s global partner network and world-class 24x7 Cisco TAC support.

While merchant silicon does speeds and feeds well, it’s not the place to find innovation. Custom software, custom hardware (ASIC), or a clever combination of the two is where new and innovative technologies will be introduced for immediate customer benefit. I don’t see that changing one bit. And you can bet Cisco will continue to lead in this arena.

There is a significant trend underway in software driven innovations, such as software defined networking (SDN). At some point you can only drive so many features into hardware so fast, while the innovation potential and velocity of software development is almost limitless, as far as I can tell. Some will say SDN means the end of custom hardware, just use merchant silicon everywhere and innovate only in software. Sorry, I don’t buy it. I tend to believe the best possible outcomes will result from an intentional mix of purpose-built software (SDN) and purpose-built hardware (ASIC).

Those that are only capable of innovating in one of the two areas (hardware or software) will do OK. However those that can engineer both software and hardware innovations in a single system are best positioned for the next wave of innovation, IMHO.

Juniper QFabric

I have to give credit to Juniper for reaching into new territory with QFabric. It’s an interesting and bold concept. There, I said it.

Bold in the sense that Juniper is asking the customer to invest in one giant proprietary 128 “slot” switch. Most people are comfortable with an 18-slot switch, it’s not too much capacity to commit to one vendor, and not too big a failure domain. But a 128 slot switch? That’s unprecedented territory. I’ll be curious to see to how well that message is received once QFabric becomes a reality (still slideware as of today).

Interesting in the sense that each edge QF-Node has the posture much like a distributed forwarding linecard in a chassis switch. One of the challenges with this architecture is hardware consistency across all of the “linecards”. Those of you familiar with distributed forwarding chassis switch architecture know that if you have a chassis full of linecards, the entire switch has to dumb down to that of the least capable card in the system, to maintain system wide consistency. I’m curious to see how that will be managed in a 128 slot QFabric as customers try to simply add or migrate in-flight to newer QF-Node edge technology.

Flat networks

“[Cisco] seemed to have missed the boat with regard to flat networks”

Really? I don’t get that. Help me understand because Cisco is the only vendor shipping a 16-way “Spine” today with FabricPath, based on TRILL. Consider that each Spine can be an 18-slot modular switch with 512 10G ports. That’s a tremendous amount of capacity and bandwidth to build very a large “flat network”, available today. There are lots of vendors talking about “flat networks”, but which ones are actually shipping?

Of course today’s offering isn’t perfect and there will be improvements. In the near future you will have Nexus 5500 supporting FabricPath, perfect for the ToR “Leaf”. You will also have newer generations of Nexus 7000 linecards with higher 10G density and L2/L3 line rate switching, supporting FabricPath as well in the same 16-way Spine topology. All of this allowing for an even larger and higher performance “flat network” than is already available today.

Cisco “missed the boat” with regard to “flat networks”? I beg to differ. The boat is actually carrying Cisco spine/leaf “flat network” gear to customer door steps today, while the others are still showing slides.


Disclaimer: The author is an employee of Cisco Systems, Inc. However, the views and opinions expressed by the author do not necessarily represent those of Cisco Systems, Inc. The author is not an official media spokesperson for Cisco Systems, Inc.