Sun Microsystems 96257 manual McData/CNT Channel Extension Interoperability

McData/CNT Channel Extension Interoperability

Figure B-6. VTSS-to-VTSS Channel Extension – Between Cascaded FICON Switches / Directors

	FICON	Channel	FICON
	Director/Switch		Director/Switch
		Extender
z/OS			CLINKs
Host	CLINKs
		Channel
		Extender
	Local		Remote
	Clustered
			Tape Silo
	VTSS
			with RTDs

Channel

Extender

Local

Tape Silo

Remote

Clustered

VTSS A502_053

■McData/CNT Channel Extension Interoperability

The following interoperability and configuration information and guidelines apply when us- ing McData/CNT USD-X and Edge3000 channel extenders with a VSM-VTSS.

Set Buffer-to-Buffer Credits at Director Ports

In FICON fabric topology, configure buffer-to-buffer (BB) credits on all director ports that are part of all channel-extended end-to-end paths to ‘extended distance’, i.e., ≥ 60 BB credits. This includes host ports, CU ports, and ISL1 ports that carry I/O on a channel-ex- tended path, regardless of which link is physically extended. For example, consider a sin- gle director configuration with three CHPIDs configured to perform I/O with two CU ports, where one CU port is channel-extended. In this case, four director ports should have their

BBcredits set to ‘extended distance’: Each of the three F_Ports attached to the three hosts, and the F_Port attached to the extension equipment that extends to the CU port.

Set Extension-Attached Director Ports to Fixed Speeds

When channel extension is added to a FICON link, the result is two FICON links which are coupled by the two channel extension chassis through a WAN. The link speed setting on at least one side of the pair of FICON links must be set to a fixed speed to avoid exposure to an issue where the link may not initialize once a fibre/SFP2 cable is attached, or where the link may not reinitialize after a loss of synchronization during operations.

1.Inter-switch link; the fibre channel link providing connectivity between two switches

2.Short form factor pluggable connectors

96257	Sun Confidential: Internal Only	B-81
	Revision A