How Does SDN Fit Into The Virtual Data Center?
One thing that needs to be cleared up is the definition of Network or Networking Hardware. In the definition of SDN from ONF they discuss the decoupling of the Control and Data Plane with the Data Plane being defined as Network Hardware. Here is where things can get confusing.
What is Network Hardware?
Wikipedia says the following :
“Networking hardware or networking equipment typically refers to devices facilitating the use of a computer network. Typically, this includes gateways, routers, network bridges, switches, hubs, and repeaters. Also, hybrid network devices such as multilayer switches, protocol converters, bridge routers, proxy servers, firewalls, network address translators, multiplexers, network interface controllers, wireless network interface controllers, modems, ISDN terminal adapters, line drivers, wireless access points, networking cables and other related hardware.”
Essentially anything that is not a end system is network hardware. The current reality of SDN is that it tends to mean Programmable Switches when it says Network Hardware. Switches are generally made built on fabrics that allow ports to transmit traffic to and from other ports.
If we were to be true to the current SDN message, we would only look at Programmable Switches. Reality is there are other ways you can create a Data Plane i.e. Network Hardware. One of these ways is using a Network Processor (which I covered in the earlier article on Vyatta).
A Computer with a few (or many) Interfaces and a Network Processor is what a Router is. We can easily see this by looking at the design of Juniper Networks Routers.
This is one of the interesting things I see in the SDN space: Companies that can take advantage of generic hardware and add value. These companies will create more tools for the architects and operators to use when pushing packets.
We plan to cover as many SDN related topics as possible here at SDN Testing, those that exist today and those that will come in the future.
Vyatta and their approach to Cloud Routers
A few weeks ago I had the pleasure of speaking with Scott Sneddon, Cloud Solutions Architect at Vyatta Inc. I’ve known Scott since the late 1990’s when he and I both worked for Exodus Communications.
Vyatta is one of the few full featured software based routing vendors in the market today. Their product is a mix of OpenSource and proprietary software combined together creating a router that can not only live in the cloud but will in the future be able to utilize some of the hardware such as Intel’s Sandy Bridge (and later generation Ivy Bridge) processors as Network Processors.
Network Processors are key to hardware forwarding routers such as the Juniper T series and the Cisco Carrier Routing System allowing them to perform forwarding and features at line rate, something that routers using software based forwarding struggle with. To get a better picture of software vs hardware forwarding you can read Router Analysis’ Enterprise Edge Router Upgrade Guide where I discuss the Cisco 7200 which uses a software forwarding engine and compare it with higher performance routers with hardware forwarding capabilities.
Vyatta offers a full featured router solution by including VPN, Firewall and other features normally found in hardware locked solutions in their software product. I feel that Vyatta has a jump on other vendors in the True Virtual Data Center space. One of the most important parts of the Virtual Data Center is the router and it’s ability to perform equal to or greater than the hardware based router it is replacing. Using software forwarding alone Vyatta claims to be able to handle up to 2Mpps, which depending on packet size can easily be multiple gigabits of traffic. In testing Vyatta is seeing up to 11Mpps using an Intel Sandy Bridge processor as a network processor.
A quick note about integrated firewalls: While software firewalls contained within the same hardware as the routers, switches and/or hosts are very useful, they are not a replacement for hardware firewalls. In security (which I do not claim to be an expert at) the separation of networks using physical links is key. There is some great information available in this thread on the Cisco support forums where they are discussing the ASA 1000V.
Vyatta keeps a tight relationship with the OpenSource community by hosting Vyatta.org where you can find free versions of Vyatta’s Core Software along with community support, documentation and forums.
SDN Testing, the software defined side of Router Analysis plans to put the Vyatta product through rigorous testing in the coming weeks.
Virtual Data Centers start to become reality.
Previously posted on Router Analysis
With the recent announcement of the CSR 1000v from Cisco, there are now two commercial Virtual Data Center stories (three if we look at the VMWare vCNS products and use one of the other vendors products for a router) Cisco and Vyatta.
What is a Virtual Data Center? There will be a lot of different answers but in my view it consists of the following:
- A pair of redundant Routers with multiple provider uplinks
- A pair of redundant Firewalls
- A pair of Load Balancers
- Front and Backend Servers
In my previous life designing and building Internet Data Centers we would have build this entire setup out of separate parts taking up an entire rack or two. Now it could be done in a single blade server with multiple redundant power supplies or a pair of highly spec’d servers.
Now, I want to be clear here: I don’t think that the software based Firewalls are up to the task of the hardware based ones. I think most security companies/consultants would agree that there is a danger when you host both your servers and your firewall on the same shared hardware. You could design the setup in a way that the ASA is only hosted on it’s own blade(s) but there is still the inherent risk of a misconfiguration or privilege escalation hack allowing someone to bypass the firewall.
Sadly the way around the security issue is to put a physical firewall in the line. This can be easily done, so it’s mainly just a CapEx issue.
For routers at this time, we only have Cisco and Vyatta commercially. They both are offering strong products but Cisco’s CSR 1000v is more feature rich supporting many protocols and features that come from using the previously designed and coded Cisco code base.
In the coming weeks and months I am going to be writing about the products available in the space and what limitations still need to be overcome. I will be working with Cisco, Vyatta, VMWare and others to try and compile as much information as possible.
Summary: The Virtual Datacenter is here. It’s not perfect, but all of the parts exist from multiple vendors. The world of Virtualization just got a lot more interesting.
What are your thoughts?
SDN stands for “Software Defined Network”, a simple name with thousands of different meanings. As defined by WikiPedia “SDN separates the control plane from the data plane in network switches and routers. Under SDN, the control plane is implemented in software in servers separate from the network equipment and the data plane is implemented in commodity network equipment.”
The most important aspect of SDN is the separation of the control and data planes. This decoupling allows end users (Service Providers, Enterprises) to use commodity hardware to build and expand their networks.
Some of the major players in the SDN space are Vyatta, Cisco, Big Switch and Nicira. Nicira was recently purchased by VMWare and is being merged into VMWares core product offerings.
Vyatta offers a Quagga based software router with firewall and VPN support. I recently talked with Vyatta and found their vision and commitment to the Open Source community great. Vyatta is currently the top player when it comes to software defined routers.
Cisco offers many of the parts needed to create SDNs but some parts have not been released yet. Cisco has released the Nexus 1000v software switch, the ASA 1000v software firewall and has announced the CSR 1000v IOS XE based software router. Once Cisco gets the full solution out, they have a chance to leapfrog over the competition due to their history and ability to re-use their current software features.
Big Switch offers an SDN Controller. Currently they are offering Floodlight, a Open Source version of their product with promises of a commercial version coming soon.
The last company I will cover is Nicira. Nicira provides what they call NVP, or the Nicira Virtualization Platform. They combine their software with the Open Source OpenVSwitch to provide a fully software controlled and forwarded network.