Tag Archives: Tofino

Network Visibility with Barefoot Deep Insight

Posted on by
2

As you may have heard this week, Barefoot Networks is back in the news with the release of their newest product, Barefoot Deep Insight. Choosing to go down the road of naming a thing after what it actually does, Barefoot has created a solution to finding out why network packets are behaving the way they are.

Observer Problem

It’s no secret that modern network monitoring is coming out of the Dark Ages. ping, traceroute, and SNMP aren’t exactly the best tools to be giving any kind of real information about things. They were designed for a different time with much less packet flow. Even Netflow can’t keep up with modern networks running at multi-gigabit speeds. And even if it could, it’s still missing in-flight data about network paths and packet delays.

Imagine standing outside of the Holland Tunnel. You know that a car entered at a specific time. And you see the car exit. But you don’t know what happened to the car in between. If the car takes 5 minutes to traverse the tunnel you have no way of knowing if that’s normal or not. Likewise, if a car is delayed and takes 7-8 minutes to exit you can’t tell what caused the delay. Without being able to see the car at various points along the journey you are essentially guessing about the state of the transit network at any given time.

Trying to solve this problem in a network can be difficult. That’s because the OS running on the devices doesn’t generally lend itself to easy monitoring. The old days of SNMP proved that time and time again. Today’s networks are getting a bit better with regard to APIs and the like. You could even go all the way up the food chain and buy something like Cisco Tetration if you absolutely needed that much visibility.

Embedding Reporting

Barefoot solves this problem by using their P4 language in concert with the Tofino chipset to provide a way for there to be visibility into the packets as they traverse the network. P4 gives Tofino the flexibility to build on to the data plane processing of a packet. Rather than bolting the monitoring on after the fact you can now put it right along side the packet flow and collect information as it happens.

The other key is that the real work is done by the Deep Insight Analytics Software running outside of the switch. The Analytics platform takes the data collected from the Tofino switches and starts processing it. It creates baselines of traffic patterns and starts looking for anomalies in the data. This is why Deep Insight claims to be able to detect microbursts. Because the monitoring platform can analyze the data being fed to it and provide the operator with insights.

It’s important to note that this is info only. The insights gathered from Deep Insight are for informational purposes. This is where the skill of network professional comes into play. By gaining perspective into what could be causing issues like microbursts from the software you gain the ability to take your skills and fix those issues. Perhaps it’s a misconfigured ECMP pair. Maybe it’s a dead or dying cable in a link. Armed with the data from the platform, you can work your networking magic to make it right.

Barefoot says that Deep Insight builds on itself via machine learning. While machine learning is seems to be one of the buzzwords du jour it could be hoped that a platform that can analyze the states of packets can start to build an idea of what’s causing them to behave in certain ways. While not mentioned in the press release, it could also be inferred that there are ways to upload the data from your system to a larger set of servers. Then you can have more analytics applied to the datasets and more insights extracted.

Tom’s Take

The Deep Insight platform is what I was hoping to see from Barefoot after I saw them earlier this year at Networking Field Day 14. They are taking the flexibility of the Tofino chip and the extensibility of P4 and combining them to build new and exciting things that run right alongside the data plane on the switches. This means that they can provide the kinds of tools that companies are willing to pay quite a bit for and do it in a way that is 100% capable of being audited and extended by brilliant programmers. I hope that Deep Insight takes off and sees wide adoption for Barefoot customers. That will be the biggest endorsement of what they’re doing and give them a long runway to building more in the future.

Tomahawk II – Performance Over Programmability

Posted on by
3

tomahawk2

Broadcom announced a new addition to their growing family of merchant silicon today. The new Broadcom Tomahawk II is a monster. It doubles the speed of it’s first-generation predecessor. It has 6.4 Tbps of aggregate throughout, divided up into 256 25Gbps ports that can be combined into 128 50Gbps or even 64 100Gbps ports. That’s fast no matter how you slice it.

Broadcom is aiming to push these switches into niches like High-Performance Computing (HPC) and massive data centers doing big data/analytics or video processing to start. The use cases for 25/50Gbps haven’t really changed. What Broadcom is delivering now is port density. I fully expect to see top-of-rack (ToR) switches running 25Gbps down to the servers with new add-in cards connected to 50Gbps uplinks that deliver them to the massive new Tomahawk II switches running in the spine or end-of-row (EoR) configuration for east-west traffic disbursement.

Another curious fact of the Tomahawk II is the complete lack of 40Gbps support. Granted, the support was only paid lip service in the Tomahawk I. The real focus was on shifting to 25/50Gbps instead of the weird 10/40/100Gbps split we had in Trident II. I talked about this a couple of years ago and wasn’t very high on it back then, but I didn’t know the level of apathy people had for 40Gbps uplinks. The push to 25/50Gbps has only been held up so far by the lack of availability of new NICs for servers to enable faster speeds. Now that those are starting to be produced in volume expect the 40Gbps uplinks to be a relic of the past.

A Foot In The Door

Not everyone is entirely happy about the new Broadcom Tomahawk II. I received an email today with a quote from Martin Izzard of Barefoot Networks, discussing their new Tofino platform. He said in part:

Barefoot led the way in June with the introduction of Tofino, the world’s first fully programmable switches, which also happen to be the fastest switches ever built.

It’s true that Tofino is very fast. It was the first 6.4 Tbps switch on the market. I talked a bit about it a few months ago. But I think that Barefoot is a bit off on its assessment here and has a bit of an axe to grind.

Barefoot is pushing something special with Tofino. They are looking to create a super fast platform with programmability. P4 is not quite an FPGA and it’s not an ASIC. It’s a switch stripped to its core and rebuilt with a language all its own. That’s great if you’re a dev shop or a niche market that has to squeeze every ounce of performance out of a switch. In the world of cars, the best analogy would be looking at Tofino like a specialized sports car like a Koenigsegg Agera. It’s very fast and very stylish, but it’s purpose built to do one thing – drive really fast on pavement and carry two passengers.

Broadcom doesn’t really care about development shops. They don’t worry about niche markets. Because those users are not their customers. Their customers are Arista, Cisco, Brocade, Juniper and others. Broadcom really is the Intel of the switching world. Their platforms power vendor offerings. Buying a basic Tomahawk II isn’t something you’re going to be able to do. Broadcom will only sell these in huge lots to companies that are building something with them. To keep the car analogy, Tomahawk II is more like the old F-body cars produced by Chevrolet that later went on to become Camaros, Firebirds, and Trans Ams. Each of these cars was distinctive and had their fans, but the chassis was the same underneath the skin.

Broadcom wants everyone to buy their silicon and use it to power the next generation of switches. Barefoot wants a specialist kit that is faster than anything else on the market, provided you’re willing to put the time into learning P4 and stripping out all the bits they feel are unnecessary. Your use case determines your hardware. That hasn’t changed, nor is it likely to change any time soon.

Tom’s Take

The data center will be 25/50/100Gbps top to bottom when the next switch refresh happens. It could even be there sooner if you want to move to a pod-based architecture instead of more traditional designs. The odds are very good that you’re going to be running Tomahawk or Tomahawk II depending on which vendor you buy from. You’re probably only going to be running something special like Tofino or maybe even Cavium if you’ve got a specific workload or architecture that you need performance or programmability.

Don’t wait for the next round of hardware to come out before you have an upgrade plan. Write it now. Think about where you want to be in 4 years. Now double your requirements. Start investigating. Ask your vendor of choice what their plans are. If their plans stink, as their competitor. Get quotes. Get ideas. Be ready for the meeting when it’s scheduled. Make sure you’re ready to work with your management to bury the hatchet, not get a hatchet jobbed network.

Running Barefoot – Thoughts on Tofino and P4

Posted on by
1

barefootgrass

The big announcement this week is that Barefoot Networks leaped out of stealth mode and announced that they’re working on a very, very fast datacenter switch. The Barefoot Tofino can do up to 6.5 Tbps of throughput. That’s a pretty significant number. But what sets the Tofino apart is that it also uses the open source P4 programming language to configure the device for everything, from forwarding packets to making routing decisions. Here’s why that may be bigger than another fast switch.

Feature Presentation

Barefoot admits in their announcement post that one of the ways they were able to drive the performance of the Tofino platform higher was to remove a lot of the accumulated cruft that has been added to switch software for the past twenty years. For Barefoot, this is mostly about pushing P4 as the software component of their switch platform and driving adoption of it in a wider market.

Let’s take a look at what this really means for you. Modern network operating systems typically fall into one of two categories. The first is the “kitchen sink” system. This OS has every possible feature you could ever want built in at runtime. Sure, you get all the packet forwarding and routing features you need. But you also carry the legacy of frame relay, private VLANs, Spanning Tree, and a host of other things that were good ideas at one time and now mean little to nothing to you.

Worse yet, kitchen sink OSes require you to upgrade in big leaps to get singular features that you need but carry a whole bunch of others you don’t want. Need routing between SVIs? That’s an Advanced Services license. Sure, you get BGP with that license too, but will you ever use that in a wiring closet? Probably not. Too bad though, because it’s built into the system image and can’t be removed. Even newer operating systems like NX-OS have the same kitchen sink inclusion mentality. The feature may not be present at boot time, but a simple command turns it on. The code is still baked into the kernel, it’s just loaded as a module instead.

On the opposite end of the scale, you have newer operating systems like OpenSwitch. The idea behind OpenSwitch is to have a purpose built system that does a few things really, really well. OpenSwitch can build a datacenter fabric very quickly and make it perform well. But if you’re looking for additional features outside of that narrow set, you’re going to be out of luck. Sure, that means you don’t need a whole bunch of useless features. But what about things like OSPF or Spanning Tree? If you decide later that you’d like to have them, you either need to put in a request to have it built into the system or hope that someone else did and that the software will soon be released to you.

We Can Rebuild It

Barefoot is taking a different track with P4. Instead of delivering the entire OS for you in one binary image, they are allowing you to build the minimum number of pieces that you need to make it work for your applications. Unlike OpenSwitch, you don’t have to wait for other developers to build in a function that you need in order to deploy things. You drop to an IDE and write the code you need to forward packets in a specific way.

There are probably some people reading this post that are nodding their heads in agreement right now about this development process. That’s good for Barefoot. That means that their target audience wants functionality like this. But Barefoot isn’t for everyone. The small and medium enterprise isn’t going to jump at the chance to spend even more time programming forwarding engines into their switches. Sure, the performance profile is off the chart. But it’s also a bit like buying a pricy supercar to drive back and forth to the post office. Overkill for 98% of your needs.

Barefoot is going to do well in financial markets where speed is very important. They’re also going to sell into big development shops where the network team needs pared-down performance in software and a forwarding chip that can blow the doors off the rest of the network for East <-> West traffic flow. Give that we haven’t seen a price tag on Tofino just yet, I would imagine that it’s priced well into those markets and beyond the reach of a shop that just needs two leaf nodes and a spine to connect them. But that’s exactly what needs to happen.

Tom’s Take

Barefoot isn’t going to appeal to shops that plug in a power cable and run a command to provision a switch. Barefoot will shine where people can write code that will push a switch to peak performance and do amazing things. Perhaps Barefoot will start offering code later on that gives you the ability to program basic packet forwarding into a switch or routing functions when needed without the requirement of taking hours of classes on P4. But for the initial release, keeping Tofino in the hands of dev shops is a great idea. If for no other reason than to cut down on support costs.