HP StorageWorks 2.128 SAN Director Switch - Manual (Page 231)

Fabric OS 5.x administrator guide 231
C Using the HP Remote Switch feature
The HP Remote Switch feature (Remote Switch), which aids in ensuring gateway compatibility, was
formerly a licensed feature. Its functionality is now available as part of the Fabric OS standard feature set
through the use of the
portCfgIslMode
command, which is described in ” Linking through a gateway ”
on page 33.
Remote Switch, enables you to connect two remote HP StorageWorks switches over an IP network,
enabling communication of IP or ATM protocols as well as Fibre Channel traffic.
The Remote Switch functions with the aid of a bridging device or Fibre Channel gateway. The gateway
supports both a Fibre Channel physical interface and a secondary, non-Fibre Channel physical interface,
such as IP, SONET, or ATM. Remote Switch functions over E_Port connections. With Remote Switch on
both fabrics, the gateway accepts Fibre Channel frames from one fabric, tunnels them across the network,
and passes them to the other fabric. From the viewpoint of the connected hosts and storage devices,
fabrics using Remote Switch interact the same as locally connected switches.
Remote Switch provides many of the same capabilities of normal ISL links including the following:
• Coordinated fabric services: The Remote Switch fabric configuration fully supports all fabric services,
including distributed name service, RSCN, and alias service.
• Distributed management: Management tools, such as Advanced Web Tools, Fabric OS, and SNMP
are available from both the local switch and the remote switch. Switch management is routed through
the Fibre Channel connection; thus, no additional network connection is required between sites.
• Support for ISLs: Sites requiring redundant configurations can connect multiple E_Ports to remote sites
by using multiple gateways. Standard Fabric OS routing facilities maximize throughput and provide
failover during interruption on the wide area network (WAN) connection.
The Remote Switch feature operates with a gateway. The gateway provides an E_Port interface that links
to the E_Port. After the link between the two E_Ports has been negotiated, the gateway E_Port moves to
passthrough mode and passes Fibre Channel traffic from the E_Port to the WAN.
The gateway accepts Fibre Channel frames from one side of a Remote Switch fabric, transfers them
across a WAN, and passes them to the other side of the Remote Switch fabric.
Remote Switch can be used for these types of gateway devices:
• Fibre Channel over ATM
• Fibre Channel over IP
• Fibre Channel over SONET
• Fibre Channel over DWDM
Most of these gateway devices have enough buffers to cover data transfer over a WAN. The HP
StorageWorks switches on each side of the gateway must have identical configurations. Only qualified
SFPs should be used.
You must connect the fabrics through the gateway device, and make sure that the
configure
parameters are compatible with the gateway device.
You might be required to reconfigure the following parameters, depending on the gateway requirements:
NOTE: Consult your gateway vendor for supported and qualified configurations.
• R_A_TOV: Specify a Resource Allocation Timeout Value compatible with your gateway device.
• E_D_TOV: Specify an Error Detect Timeout Value compatible with your gateway device
• Data field size: Specify the maximum Fibre Channel data field reported by the fabric. Verify the
maximum data field size the network-bridge can handle. Some bridges might not be able to handle a
maximum data field size of 2112.
• BB credit: Specify the number of Buffer-to-Buffer credits for Nx_Port devices.