Consider the following steps when you are planning for your FCIP TCP/IP links: 

GLYPH<SM590000> For redundancy purposes use as many TCP/IP links between sites as you have fabrics in each site that you want to connect. In most cases, there are two SAN FC fabrics in each site, so you need two TCP/IP connections between sites. 

GLYPH<SM590000> Try to dedicate TCP/IP links only for storage interconnection. Separate them from other LAN/WAN traffic. 

GLYPH<SM590000> Make sure that you have a service level agreement (SLA) with your TCP/IP link vendor that meets your needs and expectations. 

GLYPH<SM590000> If you do not use Global Mirror with Change Volumes (GMCV), make sure that you have sized your TCP/IP link to sustain peak workloads. 

GLYPH<SM590000> The use of FlashSystem 9100 internal Global Mirror (GM) simulation options can help you test your applications before production implementation. You can simulate the GM environment within one FlashSystem 9100 system without partnership with another. Use the chsystem  command with the following parameters to perform GM testing: 

– gminterdelaysimulation 

– gmintradelaysimulation 

Further details on GM planning are described in Chapter 6, “Copy services” on page 141. 

GLYPH<SM590000> If you are not sure about your TCP/IP link security, enable Internet Protocol Security (IPSec) on the all FCIP devices. IPSec is enabled on the Fabric OS level, so you do not need any external IPSec appliances. 

In addition to planning for your TCP/IP link, consider adhering to the following preferred practices: 

GLYPH<SM590000> Set the link bandwidth and background copy rate of partnership between your replicating FlashSystem 9100 to a value lower  than your TCP/IP link capacity. Failing to do that can cause an unstable TCP/IP tunnel, which can lead to stopping all your remote copy relations that use that tunnel. 

GLYPH<SM590000> The best case is to use GMCV when replication is done over long distances. 

GLYPH<SM590000> Use compression on corresponding FCIP devices. 

GLYPH<SM590000> Use at least two ISLs from your local FC switch to local FCIP router. 

GLYPH<SM590000> On a Brocade SAN, use the Integrated Routing feature to avoid merging fabrics from both sites. 

For more information about FCIP, see the following publications: 

GLYPH<SM590000> IBM System Storage b-type Multiprotocol Routing: An Introduction and Implementation , SG24-7544 

GLYPH<SM590000> IBM/Cisco Multiprotocol Routing: An Introduction and Implementation , SG24-7543 

## 2.5.4 SAN extension with Business Continuity configurations 

FlashSystem 9100 HyperSwap technology provide Business Continuity solutions over metropolitan areas with distances up to 300 km. Usually this is achieved using SAN extension over WDM technology. Furthermore, in order to avoid single points of failure, multiple WDMs and physical links are implemented. When implementing these solutions, particular attention must be paid in the intercluster connectivity set up. 

