Cascaded Ficon Topology; Example Of A Switched Point-To-Point Topology - HP XP20000/XP24000 Operation Manual

Hp storageworks xp disk array mainframe host attachment and operations guide (a5951-96154, september 2010)

Hide thumbs Also See for XP20000/XP24000:

Table of Contents

Sharing a control unit through a Fibre Channel switch allows communication between a number of

channels and the control unit to occur either:

Over one switch-to-CU link, such as when a control unit has only one link to the Fibre Channel

switch, or

Over multiple-link interfaces, such as when a control unit has more than one link to the Fibre

Channel switch.

In a FICON switched point-to-point topology, one Fibre Channel link is attached to the FICON channel.

From the switch, the FICON channel communicates with a number of FICON CUs on different switch

ports. At the control unit, the control unit and device-addressing capability is the same as the

point-to-point topology. However, communication and addressing capabilities are increased for the

channel when it is connected to a Fibre Channel switch, and can use the domain and port address

portion of the 24-bit N_Port address to access multiple control units.

The communication path between a channel and a control unit consists of the physical channel path

and the logical path. In a FICON switched point-to-point topology with a single switch, the physical

paths are the Fibre Channel links (interconnection of two Fibre Channel links connected by a Fibre

Channel switch) that provide the physical transmission path between a channel and a control unit.

Figure 9 Example of a switched point-to-point topology

Cascaded FICON topology

A FICON channel in FICON native (FC) mode connects one or more processor images to a Fibre

Channel link, which connects to a Fibre Channel switch, and then dynamically through one or more

FC switch ports (internally within the switch) to a second FC switch in a remote site via FC link(s).

From the second FC switch port, a number of Fibre Channel links connect to FICON CU ports, which

interconnect with one or more control units and/or images (logical control units). This forms a cascaded

FICON topology (see the following figure). The cascaded FICON directors topology is only supported

by IBM zSeries processors.

XP Disk Array Mainframe Host Attachment and Operations Guide

Table of Contents

Storageworks xp20000 Storageworks xp24000