Brocade Access Gateway Admin Guide v6.1.0 (53-1000605-02, June 2008)

Access Gateway Administrator’s Guide 3

53-1000605-02

Access Gateway port types

Access Gateway differs from a typical fabric switch because it is not a switch; instead, it is a mode

that you enable on a switch using the ag command. After a switch is set in ag mode, it can connect

to the fabric using node ports (N_Ports). Typically fabric switches connect to the Enterprise fabric

using ISL (InterSwitch Link) ports, such as E_Ports.

Following are the Fibre Channel (FC) ports that AG uses:

• F_Port - fabric port that connects a host, HBA, or storage device to a switch in AG mode.

• N_Port - node port that connects a switch in AG mode to the F_Port of the fabric switch.

Comparison of Access Gateway ports to standard switch ports

Access Gateway multiplexes host connections to the fabric. It presents an F_Port to the host and an

N_Port to an edge fabric switch. Using N_Port ID virtualization (NPIV), AG allows multiple FC

initiators to access the SAN on the same physical port. This reduces the hardware requirements

and management overhead of hosts to the SAN connections.

A fabric switch presents F_Ports (or FL_Ports) and storage devices to the host and presents

E_Ports, VE_Ports, or EX_Ports to other switches in the fabric. A fabric switch consumes SAN

resources, such as domain IDs, and participates in fabric management and zoning distribution. A

fabric switch requires more physical ports than AG to connect the same number of hosts.

Figure 2 shows a comparison of the types of ports a switch in AG mode uses to the type of ports

that a standard fabric switch uses.

FIGURE 2 Port usage comparison

N_Port

F_Port

N_Port

F_Port

N_Port

F_Port

Hosts

Switch in AG mode

Edge Switch

Fabric

enabled

NPIV

N_Port

F_Port

E_Port

N_Port

F_Port

Hosts

Switch in standard

Fabric Switch

E_Port

Fabric

Access Gateway Ports

Fabric Switch Ports

default mode