Fibre Channel Primer

50 Fibre Channel: Connection to the Future
Login Server
The login server is a logical entity within the switch which
receives and responds to the switch login requests. The login server
also confirms or assigns the N_Port address of the node that initiates
the login. The login server can be a proxy agent to provide a name
server with the login attributes of the N_Port.
Fabric/Switch Controller
A fabric/switch controller provides both required and optional
services, such as initialization, configuration, routing management,
and optional fabric-assisted services.
Name Server
The primary function of the name server is to give all nodes
attached to a fabric the ability to discover other nodes, their attributes,
and N_Port identifiers. A node name is an 8-byte value that may be
an IEEE address (worldwide unique) or may be locally assigned. In
either case, it is unique within the switch address space. N_Port
identifiers are assigned (optionally by the login server) when login
takes place. After this point, a node or N_Port may register the
association between the node and related N_Ports. Translation for
IP address, upper-layer protocols, and classes of service supported is
also provided.
Figure 7.1 Name servers are a directory for Fibre Channel networks
l Native port identifier
l Port type
l Port name
l Node name
l Classes of service