HP 1606 FICON Administrator's Guide v6.4.0 (53-1001771-01, June 2010) - Page 54

4 Configuration requirements for switches and directors Traffic Isolation zoning The Traffic Isolation Routing feature may be used to control the flow of interswitch traffic through the Brocade 7500 SAN router or FR4-18i VE_Port or E_Port connections. This feature can be used with Allow/Prohibit settings on M-Series directors to create complete flow through paths between end points connected through M-Series and Fabric OS products. Traffic Isolation Routing uses a special zone, called a Traffic Isolation zone (TI zone), to create dedicated paths for specific traffic. For more information on Traffic Isolation Routing and creating zones, refer to the Fabric OS Administrator's Guide. When setting up TI zones in your FICON environment, it is not recommended to have failover enabled for the following reasons: • FICON Emulation will not occur on a failed over path. • FICON devices are identified at one time during channel path activation (ELP/LPE exchange) - if the paths do not fail, the MVS system will not re-issue this sequence over the recovery path. • Multiple error periods will be perceived at the connected LPARs (first link failure, movement of traffic to recovery path and then again when the primary path is restored). • There is no good way to perform a forced or controlled fallback. Keep the following best practices in mind when using TI zoning: • If TI Zones are used to provide routes for Emulated traffic then TI Zone Fail-over cannot be enabled. • Keep the configurations as simple as possible, this will make the systems more supportable. • Include virtual E_Ports in the Traffic Isolation zone. • Use TI zoning for route selection on a port-to-port basis. • Use port zoning to restrict data flows. • Look at TI zoning, link costs, and zoning definitions to understand the routing paths used in your data center. • Understand bandwidth requirements, available network resources, etc. • Collect information on all new installations or after network changes by running the portCmd --ipPerf command. • Separate disaster recovery networks from production networks. Cross-coupled configurations A cross-coupled configuration establishes Ethernet connections between pairs of Brocade 7500 SAN routers or an FR4-18i blade using both gigabit Ethernet ports so there is only one IP path between any pair. In Figure 14, there is one IP path between A and B, one IP path between A and D, one IP path between C and B, and one IP path between C and D. Either FSPF or TI Zoning may be used to control traffic. The ISL locally connecting the 7500 pair allows failover to a second one-hop path. Without the ISL, a connection failure results in a multi-hop path. For example, if the connection between A and B fails, and there is no ISL to C, traffic is routed to D, then C, and finally to B, resulting in excessive network utilization and probable failures. 42 FICON Administrator's Guide 53-1001771-01