Normally the Max concurrent Vuser to IP address is a One to one (1:1) ratio. This is depend on your Load Balancer setting and how your application assigns Sessions. When a LG(s) are setup to work with IP spoofing the software adds XX number of IPs to each LGs. These IPs are available to LoadRunner load test with the IP spoofing is enable in the Test design.
Note each LG must be assigned different IPs
EXAMPLE:
LG1 is assigned
10.10.10.1
10.10.10.2
10.10.10.3
10.10.10.4
10.10.10.5
LG2 is assigned
10.10.10.6
10.10.10.7
10.10.10.8
10.10.10.9
10.10.10.10
When running a load test with IP Spoofing enabled the Vuser are assign a IP address from the LG in a ''Round Rodin'' method (or by code from within the script)
For a 5 Vuser test with 1 LG with 5 IPs assigned the Vusers will each get an IP address to use. I if you run 10 Vuser on the LG with 5 IP addresses, Vuser 6 will use the same IP as Vuser 1
Example 2a:
5 Vuser test LG1 (with 5 IPs) the IP are assigned
10.10.10.1 --> Vuser 1
10.10.10.2 --> Vuser 2
10.10.10.3 --> Vuser 3
10.10.10.4 --> Vuser 4
10.10.10.5 --> Vuser 5
Example 2b:
10 Vuser test LG1 (with 5 IPs) the IP are assigned
10.10.10.1 --> Vuser 1, --> Vuser 6
10.10.10.2 --> Vuser 2, --> Vuser 7
10.10.10.3 --> Vuser 3, --> Vuser 8
10.10.10.4 --> Vuser 4, --> Vuser 9
10.10.10.5 --> Vuser 5, --> Vuser 10
If you application and/load balancer require a IP per user the Vusers 6 on will fail. Is some cases ,depend on how the IP session are handle both Vusers assigned to the Same IP will fail to run properly