FCoE: Converging Ethernet and SAN

Fibre Channel over Ethernet (FCoE) is an encapsulation of Fibre Channel frames over Ethernet networks. This allows Fibre Channel to use 10 Gigabit Ethernet networks (or higher speeds) while preserving the Fibre Channel protocol. In simple terms, FCoE allows running Fibre Channel protocol over 10 Gigabit ethernet. We will divide this discussion under the following heads.

1) Challanges with traditional data centers
2) Infrastructure required to implement FCoE.
3) Advantages of implementing FCoE.
4) Common challanges that enterprises face while migrating to FCoE.

Challanges with traditional data centers

A traditional data center will have separate infrastructure for Ethernet and SAN traffic. This basically would mean that every server will have a HBA and NIC. The data center will have both have an Ethernet switch and Fibre-Channel switch. There will be separate cabling for both Ethernet and SAN networks. It will look somewhat like in the following figure.

This setup has the following disadvantages.

• Since the Ethernet and SAN networks will be running parallely it will lead to overall complexity.
• High number of total number of overall adapters, cables, ports and switches.
• Underutilized bandwidth.
• High energy consumption

Infrastructure required to implement FCoE

As you can see that there is inherent complexity in the above architecture. FCoE provides a solution to this problem by converging Ethernet and SAN traffic. Let's see how. FCoE converges

• HBA and NIC into one CNA (Converged Network Adapter)
• Ethernet and FC switch into one FCoE switch
• Ethernet and Fibre-Channel cables into one FCoE cable.

This converged network is then made to run on a 10GB ethernet which provides enough bandwidth so that both Ethernet and Fibre-Channel traffic can run concurrently.

Advantages of implementing FCoE

• Reduces Complexity by 50%
• Reduces total number of adapters, cables, ports and switches
• Allows easy deploymeny in phases
• Reduction in energy consumption

Common challanges that enterprises face while migrating to FCoE

It is obvious that when you plan to adopt a new technology you are bound to face challanges. Moving to FCoE is no different. Let's look at some of the challanges that most IT admins face.

• Upper management in most of the organizations is hesistant in investing in FCoE infrastructure. Convincing them that despite of the initial investment FCoE will bring significant savings in future is a dawnting task.
• In most organizations normally there are separate teams (sometimes totally different hierarchy reporting to a different director) managing ethernet and SAN network. To implement and run FCoE successfully both of these teams need to interact and work wit each other at the deepest level possible which is not an easy task. Both the teams will need training to work with FCoE (Learning curve will be higher for LAN/WAN team)
• It is highly likely that your current vendor (For both LAN/WAN and SAN) does not has the expertise or support in FCoE infrastructure. It is also possible that switching to a different vendor will result in significant savings. If this is the situation you will have no option but to switch to a different vendor for implementing FCoE and this is not at all an east task. Most LAN/SAN adminsitrators and their teams have built-up an extensive experience in working with their current vendor. Hence a change to a different vendor is a bitter pill to swallow.

FCoE has come a long way. More and more vendors are coming with an end-to-end solution for FCoE. Recently NetApp and Cisco unveiled their End-to-End FCoE solution with VMWare. For more details look at: http://www.netapp.com/us/company/news/news-rel-20100728.html