50 Implementing the IBM Storwize V7000 with IBM Spectrum Virtualize V8.2.1
Clients might be able to use the intelligence in domain name servers (DNSs) to provide partial 
failover. Figure 3-1 shows a simple IP addressing scheme that uses a single subnet for iSCSI 
and management.
Figure 3-1   IP addressing scheme: Use of a single subnet
3.5.1  Firewall planning
After you have your IP network planned, identify network flows that are required for the 
correct functioning of the environment. The list must specify source IP address, destination IP 
addresses, and required protocols or ports for each flow. Present the list to the firewall 
administrators and request the set up of appropriate firewall rules. 
For a list of mandatory and optional network flows that are required for operating IBM SAN 
Volume Controller, search for “TCP/IP requirements for the system” at IBM Knowledge 
Center.
3.6  SAN configuration planning
Storwize V7000 cluster can be configured with a minimum of two (and up to eight) Storwize 
V7000 nodes. These nodes can use SAN fabric to communicate with back-end storage 
subsystems and hosts. 
3.6.1  Physical topology
The switch configuration in an Storwize V7000 fabric must comply with the switch 
manufacturer’s configuration rules, which can impose restrictions on the switch configuration. 
For example, a switch manufacturer might limit the number of supported switches in a SAN. 
Operation outside of the switch manufacturer’s rules is not supported.