Five Tips for I/O Consolidation and FCoE in Your Data Center

The path to a successful FCoE deployment is not as daunting as you might think.

By Ron Fuller, Technical Solutions Architect, Cisco

One of the emerging data center trends is the consolidation of I/O on to a common transport, Ethernet. This provides many benefits to the organization including reduction of infrastructure -- such things as cables, optics, ports, and Fibre Channel switches. Although reducing costs sounds appealing, you also realize that your data is invaluable and you don’t want to participate in a science fair project to implement leading-edge technology. Finding the balance between justified cost reduction and undue organizational risk is not easy, but this article can help.

First, a quick review of Fibre Channel over Ethernet (FCoE) is in order. FCoE is a full standard defined by the T11 organization in FC-BB-5 and was finalized in June 2009. FCoE enables Ethernet networks to carry native Fibre Channel frames. The Fibre Channel frame is completely encapsulated in an Ethernet frame for transport across the network. This means the same wire that carries Ethernet frames can now do double duty and transport Fibre Channel frames as well. This capability is the heart of what drives the reduction in cabling, optics, ports, and devices. The figures below illustrate the concept.

  

How can you be successful with FCoE? Follow these five tips.

Tip #1: Ensure your network supports FCoE.

FCoE, as its name implies, uses Ethernet as a transport and more than likely you have Ethernet in your data center. The real question is if the Ethernet you have is lossless Ethernet. Lossless Ethernet is the Ethernet we all use today with added capabilities to ensure FCoE frames are not dropped like traditional Ethernet frames. If we reflect back on the way Fibre Channel works, it relies on the network transport to guarantee frame delivery, like buffer-to-buffer (B2B) credits and different classes of traffic.

Ethernet networks on the other hand, rely on upper-layer protocols such as TCP to detect loss of data and retransmit the missing information. Lossless capability needed to be built into Ethernet to safely and reliably accommodate Fibre Channel traffic. Checking your current switches will be a first step towards the implementation of FCoE.

Tip #2: Upgrade to 10Gb Ethernet.

If we examine the feeds and speeds of modern networks, we immediately see a disparity between Ethernet and Fibre Channel networks. Ethernet typically runs at speeds of 10/100/1000/10000 Megabits per second (Mbps) or also annotated at 1G/10G (for Gigabits per second). Emerging technologies in Ethernet are stepping up to 40G and 100G but at this time are not priced for end-host connectivity but rather geared towards interconnections or trunks.

Fibre Channel, on the other hand, operates at 1G/2G/4G/8G with 16G and 32G emerging. If we think about how we transport an 8G Fibre Channel flow in an Ethernet topology, we see the need for 10G Ethernet. 1G Ethernet simply doesn’t have the bandwidth to carry modern Fibre Channel flows. Converged network adapters (CNAs), which are the combined Fibre Channel HBA and Ethernet NIC all in one card, are also required to connect to the FCoE network.

Tip #3: Validate the technology.

As a key stakeholder in a data center’s infrastructure, it is your responsibility to validate new technology. Due to the dramatic changes FCoE and I/O consolidation brings to the data center, you may be concerned about the operational changes it will bring. I’ve worked with many companies on understanding, validating, and implementing FCoE and each of them expressed similar concerns. Topics such as performance, interoperability, operational changes to troubleshooting and support, and change management all are top of mind. To be honest, some processes will change, but the fundamental model and roles and responsibilities don’t change. My experience has been that once you see, touch, and validate the technology, what seemed like a huge hurdle becomes a small modification of a process.

Tip #4: Deploy where it makes sense.

FCoE is an evolutionary technology, not a revolutionary one. Many seem to think FCoE is an all or nothing proposition when it really is not. FCoE has been designed from the beginning to integrate seamlessly into existing Fibre Channel networks. As we mentioned, FCoE transports the entire Fibre Channel frame in Ethernet, so the FC targets don’t need to be FCoE enabled. This means your investment in FC infrastructure is maintained while the edge of your network transforms and drives cost down.

Most companies start small in their test and development environment, as they retire or refresh their equipment. The platform of choice has been the X86 compute space primarily because of the availability of CNAs. Additionally, when calculating the financial ROI, the sheer number of X86 devices lends itself nicely to I/O consolidation, though we are seeing FCoE make its way into the bigger systems in the data center.

Tip #5: Set realistic expectations.

Although this may sound trite, setting realistic expectations is a key attribute to success. Because FCoE is evolutionary, not revolutionary. I frequently see FCoE discussed for data center interconnect (DCI). Although very appealing and something we’ll see in the near future, keep in mind that it’s still Fibre Channel. Depending on your DCI transport, the requirement for lossless delivery may not be met. In those cases, traditional transport using IP may be more appropriate. Also, FCoE isn’t the death knell for Fibre Channel -- we’ll still use it for years to come. Who still has some token ring in their network? Exactly.

The Last Word

The path to a successful FCoE deployment is not as daunting as some make out to be. It yields real world benefits for many enterprises. These five tips will help guide you as you adopt FCoE in your data center.

Ron Fuller, CCIE #5851 (Routing and Switching/Storage Networking) is a Technical Solutions Architect for Cisco specializing in data center architectures. He has 19 years of experience in the industry and has held certifications from Novell, HP, SNIA, and Cisco. His focus is working with enterprise customers to address their challenges.