Fibre Channel over Ethernet: converging SAN and LAN onto one lossless Ethernet fabric.
FCoE encapsulates FC frames into Ethernet on a lossless CEE network. Host options: CNA (hardware NIC+HBA) or software FCoE adapter (OS-resident). FCoE switch provides Ethernet bridge + FCF for FC forwarding, zoning, and fabric services.
FCoE يغلّف إطارات FC داخل Ethernet على شبكة CEE بلا فقدان. يستخدم CNA (أو Software FCoE Adapter) على السيرفر، وFCoE Switch مع FCF.
Putting FC 'cargo' into Ethernet 'trucks' so storage and data share one road.
Wrapping FC frames inside Ethernet frames.
FC frame placed in an FCoE Ethernet frame.
Converged Network Adapter — hardware NIC + HBA in one card.
10GE + FC + FCoE ASICs on one adapter.
OS/hypervisor software performing FCoE processing on a standard NIC.
Software initiator for FCoE on supported NICs.
Switch with Ethernet bridge + FCF for FCoE traffic.
Top-of-rack converged switch.
FCoE Forwarder — FC switching, login, zoning, encapsulation/decapsulation.
Routes FC frames within the converged fabric.
FCoE virtualizes FC ports over Ethernet: VN_Port (virtual node port on CNA), VF_Port (virtual fabric port on FCF), VE_Port (virtual expansion port between FCFs).
في FCoE تُحاكى منافذ FC افتراضياً فوق Ethernet: VN_Port (عقدة)، VF_Port (Fabric)، VE_Port (بين سويتشين).
The same N/F/E port roles from FC, now running virtually on Ethernet.
| FCoE Port | FC Equivalent | Role |
|---|---|---|
| VN_Port | N_Port | Node port (on CNA) |
| VF_Port | F_Port | Fabric port (on FCF) |
| VE_Port | E_Port | Switch-to-switch (FCF-to-FCF) |
A VLAN logically segments an Ethernet/LAN; a VSAN logically segments an FC SAN. Both provide logical isolation but in different networks.
VLAN يقسم شبكة Ethernet منطقياً، وVSAN يقسم شبكة FC SAN منطقياً. كلاهما عزل منطقي لكن في عالمين مختلفين.
VLAN partitions the data 'building'; VSAN partitions the storage 'building'.
| Aspect | VLAN | VSAN |
|---|---|---|
| Network | Ethernet / LAN | Fibre Channel / SAN |
| Purpose | Segment broadcast domains | Segment fabric / isolate SAN traffic |
| Isolation | Layer 2 LAN | FC fabric services |
FCoE connectivity modes: (1) FCoE with existing FC SAN — FCoE switches bridge CEE network to FC SAN storage; (2) End-to-end FCoE — both compute and storage are FCoE-native, suitable for new deployments.
FCoE إما يتصل بـ FC SAN موجود (CNA → FCoE Switch → FC Storage) أو End-to-End حيث التخزين والسيرفرات كلاهما FCoE.
Existing FC SAN = adding a translation layer; end-to-end = everyone speaks the same converged language.
| Mode | Compute | Storage | Use Case |
|---|---|---|---|
| With existing FC SAN | CNA (FCoE) | FC ports | Leverage existing FC investment |
| End-to-end FCoE | CNA (FCoE) | FCoE ports | New greenfield deployment |
Converged Enhanced Ethernet (CEE/DCB) makes Ethernet lossless for FCoE: PFC (Priority Flow Control — pause per traffic class), ETS (Enhanced Transmission Selection — bandwidth allocation), CN (Congestion Notification), DCBX (DCB Exchange protocol — negotiates DCB settings).
لجعل Ethernet بلا فقدان (Lossless) لـ FCoE، أُضيفت تحسينات CEE: PFC للتحكم بالتوقف لكل أولوية، ETS لتوزيع النطاق، CN للتحكم بالازدحام، وDCBX لتبادل الإعدادات.
Traffic management for a shared road: PFC = lane-specific stop signs, ETS = lane width allocation, CN = congestion alerts, DCBX = agreeing on the rules.
Priority Flow Control — pauses specific traffic classes to prevent drops.
Pauses storage traffic class without stopping LAN.
Enhanced Transmission Selection — allocates bandwidth per class.
Guarantees 40% bandwidth to FCoE.
Congestion Notification — signals congestion back to the source.
Source slows down on congestion.
DCB Exchange — negotiates/exchanges DCB capabilities.
Switch and CNA agree on PFC/ETS config.
FCoE process: (1) Discovery — FCFs discover each other, nodes find FCFs; (2) Login — virtual FC links created, VN_Port gets FC address and MAC; (3) Data transfer — encapsulated FC frames over CEE. FIP handles discovery/login (FIP Solicitation, Advertisement, FLOGI). Addressing: FPMA (fabric-provided MAC) or SPMA (server-provided MAC).
FCoE يمر بثلاث مراحل: Discovery (اكتشاف FCF)، Login (إنشاء روابط VN/VF)، Data Transfer. FIP يدير الاكتشاف والتسجيل. العنونة: FPMA من الـ Fabric أو SPMA من السيرفر.
FIP = the check-in process; FPMA = the venue assigns your badge number; SPMA = you bring your own badge.
Finds FCFs and establishes virtual links over Ethernet.
CNA discovers available FCFs.
Performs FLOGI/FDISC over Ethernet to join the fabric.
VN_Port logs into the FCF.
Fabric Provided MAC Address (FC-MAP + FCID).
Most common; fabric assigns the MAC.
Server Provided MAC Address (server-assigned).
Server provides its own MAC.
FCoE reduces network adapters, cables, power consumption, and rack space in the data center. Protocol stack: SCSI/FCP → FC-2 → FCoE → Ethernet (CEE/lossless). FC protocol layers (FC-0 through FC-4) operate inside the FCoE encapsulation.
FCoE يقلل عدد adapters وكابلات واستهلاك الطاقة والمساحة في مركز البيانات. الـ stack: FCoE PDU → Ethernet → CEE (lossless). FC layers (FC-0 to FC-4) تعمل داخل FCoE frame.
One converged highway carrying both commuter (LAN) and freight (SAN) traffic with dedicated lanes (PFC).
Protocol Data Unit — encapsulated FC frame in Ethernet.
FC payload wrapped for CEE transport.
24-bit prefix in FPMA MAC address assigned by fabric.
MAC = FC-MAP (24 bits) + FCID (24 bits).
CEE/DCB Ethernet that never drops storage frames.
PFC pauses FCoE traffic class instead of dropping.
| Protocol | Network | Use Case | TCP? |
|---|---|---|---|
| FCoE | Lossless Ethernet | Converged LAN+SAN in DC | No |
| iSCSI | Standard IP/Ethernet | Host to block storage | Yes |
| FCIP | IP/WAN | Remote SAN extension | Yes |