HP 316095-B21 - StorageWorks Edge Switch 2/24 Planning Manual page 89

SAN High Availability Planning Guide
— No response from attached switch — After a fabric is created, each
element in the fabric periodically verifies operation of all attached
switches and directors. An ISL segments if a director or switch does not
respond to a verification request.
— ELP retransmission failure timeout — A director or switch that
exhibits a hardware failure or connectivity problem cannot transmit or
receive Class F frames. The director or switch did not receive a response
to multiple exchange link parameters (ELP) frames, did not receive a
fabric login (FLOGI) frame, and cannot join an operational fabric.
Fabric services and state change notifications — In a multi-switch fabric,
services provided by each director or switch (such as name service, registered
state change notifications [RSCNs], and zoning) are provided on a
fabric-wide basis. For example, if a fabric-attached device queries a director
or switch name server to locate all devices that support a specified protocol,
the reply includes all fabric devices that support the protocol that are in the
same zone as the requesting device, not just devices attached to the director or
switch.
RSCNs are transmitted to all registered device N_Ports attached to the fabric
if either of the following occur:
— A fabric-wide event occurs, such as a director or switch logging in to the
fabric, a director or switch logging out of the fabric, or a reconfiguration
because of a director, switch, or ISL failure.
— A zoning configuration changes.
Zoning configurations for joined fabrics — In a multi-switch fabric, zoning
is configured on a fabric-wide basis, and any change to the active zone set is
applied to all directors and switches. To ensure zoning is consistent across a
fabric, the following rules are enforced when two fabrics (zoned or unzoned)
join through an ISL.
— Fabric A unzoned and Fabric B unzoned — The fabrics join
successfully, and the resulting fabric remains unzoned.
— Fabric A zoned and Fabric B unzoned — The fabrics join successfully,
and fabric B automatically inherits the zoning configuration from fabric
A.
— Fabric A unzoned and Fabric B zoned — The fabrics join successfully,
and fabric A automatically inherits the zoning configuration from fabric
B.
Planning Considerations for Fibre Channel Topologies
89