Port names in FC/FCoE Topology

Following are most common port names used in FC/FCoE Technology:

N_port(Node port)/VN_port:

  • Ports on end host(i:e HBA) and storage array(target port) are called as N_port in FC topology.
  • Called as VN_port in FCoE terminology.
  • HBA’s that handles IP traffic are called as CNA in FCoE terminology.
  • Each N-port will have a unique WWPN (64 bit) assigned by vendor. We use this WWPN while configuring Zoning on FC switch.
  • Fabric Provided Mac Address (FPMA) is a 48-bit mac-address that uniquely identifies a single VN_port(CNA) on an Enode. FPMA is assigned to an VN_port by FC switch during FLOGI process.
  • FPMA (48-bit mac) = FC-map (24 bits) + FC_ID (24 bits)
    • FC-MAP: 24 bit value that identifies the FC switch. Default value: 0efc00
    • FC_ID:  Also called as N_port ID. A 24-bit value assigned to a VN_Port by the FC switch to uniquely identify it in the local fabric network.
  • So, there will be one-one mapping between physical N-port WWPN and FPMA/N_port ID in a fabric network.

F_port(Fabric port):

  • Ports on the FC switch that is connected to N-port
  • Called as VF_port in FCoE terminology.

E_port(Expansion Port):

  • Interconnecting ports between the FC switches.
  • Called as VE-ports in FCoE terminology.
  • Link connecting two E-ports are called ISL(Inter-switch link)

E_node(Ethernet Node) is the end host that equips CNA.

So, a CNA will have three MAC addresses:

  • Universal MAC (Assigned by vendor for IP traffic)
  • E-node MAC (Assigned by vendor for FIP protocol)
  • VN-port MAC(allocated by FC switch to use for FCoE frames).






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One Response to Port names in FC/FCoE Topology

  1. Pingback: NPG (NPIV Proxy Gateway) Mode Vs Full Fabric Mode in FCoE | Internet Protocols

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