Well Known Addresses

          Every switch has reserved three byte addresses known as Well Known Addresses. The services residing at these addresses provide a service to either nodes or management applications in the fabric.

           Fabric Login : Before a fabric node can communicate with services on the switch or other nodes in the fabric an address is assigned by the fabric login server.

           Directory Server/Name server: The directory server/name server is where fabric/public nodes register themselves and query to discover other devices in the fabric.

            The fabric controller provides state change notifications to registered nodes when a change in the fabric topology occurs

Control Flow :

1. Fabric Login (Flogi) from host to switch at FFFFFE  (FABRIC LOGIN)

2. Switch(FFFFFE) responds with an ACCEPT

3. Host does an N-port login (Plogi) to the switch at FFFFFC

4. Switch FFFFFC Accepts

5. Host registers (SCR) to receive RSCN at FFFFFD

5. Host can then

       a) Register attributes

       b) Query for devices

6. Switch(FFFFFC) will respondas appropriate for type of request

7. Host may logout the Name Server (LOGO)- not the Fabric

SAN Attached Initiators and Target

        Initiator Communication Process Review

             Fabric Initiators are typically server HBAs that will:

             FLOGI to FFFFFE and obtain 24-bit Fabric address

             PLOGI to FFFFFC

                SCR to FFFFFD

                Register and query FFFFFC for database of Storage/Tape targets

  

                      FFFFFC matches HBA to zones (Fabric subsets containing devices you“allow” to communicate) and returns 24-bit addresses of targets that HBA requested within authorized  zones

 

                      PLOGI and then sends SCSI probes to fabric destination addresses of targets returned from Name Server

Assign target ids (with server OS) to each node