After reading several white papers from various vendors and listening to hours of computer based training I think I have finally wrapped my head around this technology and decided to share it with you here at a high level, so I will call this the introduction to a Series in FCoE and dig deeper into the technology as time progresses.
Fibre Channel over Ethernet or commonly referred as FCoE is the technology that encapsulates Fibre Channel (FC) frames over a Ethernet packet. Ethernet is everywhere let’s face it, the technology is not going anywhere, so let’s explore the FCoE technology that is gaining more and more popularity due to the 10, 40 & 100GBE transmit rates with its primary use case being in the Storage world of course.
First let’s briefly define some common terminology associated with FCoE, and then get into the weeds of how this thing really works.
- Unified Fabric: Combining multiple types of traffic IE. Ethernet and SAN on the same physical link, leveraging the CNA (Converged Network Adapter) that processes both traffic types.
- FIP (FCOE initialization Protocol) A integral part of the process which basically gets the conversation going it is the control plane protocol used in the discovery and initialization stages of establishing the links in the Fabric. FIP frames contain discovery and Login/Logout parameters in its simplest form.
- DCB (Data Center Bridging): A requirement that uses priority based flow control that allows the lossless Ethernet capability’s utilizing pause frames and priority pause frames, which you could look at as splinting a single link into several links to prioritize traffic at a granular level with control. Another aspect of DCB is Enhanced transmission selection (ETC) which prioritizes and allocates traffic with different characteristics of traffic classes.
- CoS (Class of service): Is the method to manage multiple traffic types using tags providing traffic priorities
Additional Notes:
- FCoE Port Types: VN, VF, VE and VNP which are similar to the Node, Fabric, Expansion & Node Port Virtualization ports they are simply virtual ports in the world of FCoE that have similar functionality.
- FCoE frames are 2242 Byte Jumbo Frames
FCoE Stoarge Specific Set Up Example:
NetApp CDOT
- FCoE must be configured at the switch level before your FC service can run over the existing Ethernet infrastructure.
- Verifying the license for FC
- Enabling block access for a Vserver with FC
- create LIFs for a Vserver and assign the FC protocol to those LIFs
- Create LUNs and map igroups for FC