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Dell’s distributed core

TechOps Guy: Nate

Dell's Force10 unit must be feeling the heat from the competition. I came across this report which the industry body Tolly did on behalf of Dell/Force10.

Normally I think Tolly reports are halfway decent although they are usually heavily biased towards the sponsor (not surprisingly). This one though felt light on details. It felt like they rushed this to market.

Basically what Force10 is talking about is a distributed core architecture with their 32-port 40GbE Z9000 switches as what they call the spine(though sometimes they are used as the leaf), and their 48-port 10 GbE S4810 switches as what they call the leaf (though sometimes they are used as the spine).

They present 3 design options:

Force10 Distributed Core Design

I find three things interesting about these options they propose:

  • The minimum node count for spine is 4 nodes
  • They don't propose an entirely non blocking fabric until you get to "large"
  • The "large" design is composed entirely of Z9000s, yet they keep the same spine/leaf configuration, whats keeping them from being entirely spine?

The distributed design is very interesting, though it would be a conceptual hurdle I'd have a hard time getting over if I was in the market for this sort of setup. It's nothing against Force10 specifically I just feel safer with a less complex design (I mentioned before I'm not a fan of stacking for this same reason), less things talking to each other in such a tightly integrated fashion.

That aside though a couple other issues I have with the report is while they do provide the configuration of the switches (that IOS-like interface makes me want to stab my eyes with an ice pick) - I'm by no means familiar with Force10 configuration and they don't talk about how the devices are managed. Are the spine switches all stacked together? Are the spine and leaf switches stacked together? Are they using something along the lines of Brocade's VCS technology? Are the devices managed independently and they are relying on other protocols like MLAG? The web site mentions using TRILL at layer 2, which would be similar to Brocade.

The other issue I have with the report is the lack of power information, specifically would be interested (slightly, in the grand scheme of things I really don't think this matters all that much) in the power per usable port (ports that aren't being used for up links or cross connects). They do rightly point out that power usage can vary depending on the workload and so it would be nice to get power usage based on the same workload. Though conversely it may not matters as much, looking at the specs for the Extreme X670V (48x10GbE + 4x40GbE) says there is only 8 watts of difference between (that particular switch) 30% traffic load and 100% traffic load, seems like a trivial amount.

Extreme Networks X670V Power Usage

As far as I know the Force10 S4810 switch uses the same Broadcom chipset as the X670V.

On their web site they have a nifty little calculator where you input your switch fabric capacity and it spits out power/space/unit numbers. The numbers there don't sound as impressive:

  • 10Tbps fabric = 9.6kW / 12 systems / 24RU
  • 15Tbps fabric = 14.4kW / 18 systems / 36RU
  • 20Tbps fabric = 19.2kW / 24 systems / 48RU

The aforementioned many times Black Diamond X-Series comes in at somewhere around 4kW (well if you want to be really conservative you could say 6.1kW assuming 8.1W/port which their report was likely high considering system configuration) and a single system to get up to 20Tbps of fabric(you could perhaps technically say it is has 15Tbps of fabric since the last 5Tbps is there for redundancy, 192 x 80Gbps = 1.5Tbps). 14.5RU worth of rack space too.

Dell claims non-blocking scalability up to 160Tbps, which is certainly a lot! Though I'm not sure what it would take for me to make the leap into a distributed system such as TRILL. Given TRILL is a layer 2 only protocol (which I complained about a while ago), I wonder how they handle layer 3 traffic, is it distributed in a similar manor? What is the performance at layer 3? Honestly I haven't read much on TRILL at this point (mainly because it hasn't really interested me yet), but one thing that is not clear to me(maybe someone can clarify), is is TRILL just a traffic management protocol or does it also include more transparent system management(e.g. manage multiple devices as one), or does that system management part require more secret sauce by the manufacturer.

My own, biased(of course), thoughts on this architecture, while innovative:

  • Uses a lot of power / consumes a lot of space
  • Lots of devices to manage
  • Lots of connections - complicated physical network
  • Worries over resiliency of TRILL (or any tightly integrated distributed design - getting this stuff right is not easy)
  • On paper at least seems to be very scalable
  • The Z9000 32-port 40GbE switch certainly seems to be a nice product from a pure hardware/throughput/formfactor perspective. I just came across Arista's new 1U 40GbE switch and I think I'd prefer the Force10 design with twice the size and twice the ports purely for more line rate ports in the unit.

It would be interesting to read a bit more in depth about this architecture.

I wonder if this is going to be Force10s approach going forward, the distributed design, or if they are going to continue to offer more traditional chassis products for customers who prefer that type of setup. In theory it should be pretty easy to do both.

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I called it! – Force10 bought by Dell

TechOps Guy: Nate

Not that it matters to me too much either way but Dell just bought Force10. I called it! Well it matters to me in that I didn't want Dell near my Extreme Networks :)

It is kind of sad that Force10 was never able to pull off their IPO. I have heard that they have been losing quite a bit of talent recently, but don't know to what degree. It's also unfortunate they weren't able to fully capitalize on their early leadership in the 10 gigabit arena, Arista seems to be the new Force10 in some respects, though it wouldn't surprise me if they have a hard time growing too barring some next gen revolutionary product.

I wonder if anyone will scoop up BlueArc, they have been trying to IPO as well for a couple of years now, I'd be surprised if they can pull it off in this market.  They have good technology just a whole lot of debt. Though recently I read they started turning a profit..


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Who’s next

TechOps Guy: Nate

I was thinking about this earlier this week or late last week I forget.

It wasn't long ago that IBM acquired Blade Network Technologies, a long time partner of IBM as Blade made a lot of switches for the Blade Center, and also for the HP blade system as well I believe.

I don't think that Blade Networks was really well known outside of their niche of being a supplier to HP and IBM (and maybe others I don't recall and haven't checked recently) on the back end. I certainly never heard of them until in the past year or two and I do keep my eyes out there for such companies.

Anyways that is what started my train of thought. The next step in the process was watching several reports on CNBC about companies pulling their IPOs due to market conditions. Which to me is confusing considering how high the "market" has come recently. It apparently just boils down to investors and IPO companies not able to agree on a "market price" or whatever. I don't really care what the reason is, but the point is this -- earlier this year Force10 Networks filed for IPO, and well haven't heard much of a peep since.

Given the recent fight over 3PAR between Dell and HP, and the continuing saga of stack wars, it got me speculating.

What I think should happen, is Dell should go buy Force10 before they IPO. Dell obviously has no networking talent in house, last I recall their Powerconnect crap was OEM'd from someone like SMC or one of those really low tier providers. I remember someone else making the decision to use that product last year, and then when we tried to send 5% of our network traffic to the site that was running those switches they flat out died, had to get remote hands to reboot them. Then shortly afterwards one of them bricked themselves when upgrading the firmware on them, had to RMA. I just pointed and laughed, since I knew it was a mistake to go with them to begin with, the people making the decisions just didn't know any better. Several outages later they ended up replacing them, and I tought them the benefits of a true layer 3 network, no more static routes.

Then HP should go buy Extreme Networks, which is my favorite network switching company, I think HP could do well with them. Yes we all know HP bought 3COM last year, but we also know HP didn't buy 3COM for the technology (no matter what the official company line is), they bought them for their presence in China. 3COM was practically a Chinese company by the time HP bought them, really! And yes I did read the news that HP finished kicking Cisco out of their data centers replacing their stuff with a combination of Procurve and 3COM. Juniper tried & failed to buy Extreme a few years ago shortly after they bought Netscreen.

That would make my day though, a c-Class blade system with an Extreme XOS-powered VirtualConnect Ethernet fabric combined with 3PAR storage on the back end. Hell, that'd make my year :)

And after that, given that HP bought Palm earlier in the year (yes I own a Palm Pre - mainly so I can run older Palm apps otherwise I'd still be on a feature phone). HP likes the consumer space so they should go buy Tivo and break into the set top box market. Did I mention I use Tivo too? I have 3 of them.


What a mouthful

TechOps Guy: Nate

I've thought about this off and on and I better write about it so I can forget about it.

I think Force10 is way too verbose in choosing the phrase to describe their company, it's quite a mouthful -

Force10 Networks, Inc., a global technology leader that data center, service provider and enterprise customers rely on when the network is their business[..]

I like Force10, I have been watching them for five years now, I just think any phrase you choose to describe your company should be short enough to say it in one (casual) breath.

How about "Force10 Networks Inc., a global networking technology leader".

Force10's marketers are very nice folks I've sent them two corrections over the years to their web site(one concerning the number of ports a competitor offers in their products, the other with a math error in a graphic showing much you can save on their products), they were very kind and responsive(and fixed both problems pretty quickly too). This one I won't send to them directly since it's more than a cosmetic change :)

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