V Model stands for Verification and Validation.

The V Model is a more interactive model which requires the
testing team to involve after the FRS is prepared. There is
much scope for adding the new features into the application
at any stage of the application. The testing phases are in
congruence with the development phases, for ex. while the
Coding happens, simultaneously the WBT also happens.

BUssiness Requirements(BR)- ----------> User Acceptence Testing
       \                                      /
     System Requirements(SRS)---------------> System Testing
         \                                    /
 High Level Design(HLD)--------------> System Integratioon
Testing
            \                                /
Low Level Design(LLD)--------> Component Integration Testing
               \                           /
             Coding  ---------->  Unit Testing
                  \                     /
                    \                  /
                      \               /
                        \            /
                            Build


V Model is a popular Software development model. It large
number of resources to implement.
In v model every development stage will have corresponding
testing stage.
Here test will be prepared in parallel with development phases.
i.e
After receiving  the business requirements are prepared 
then testing team will develop User acceptence Testcases.
But these testcases will be executed and the end of the project.

Here Business Requirements are very abstract in nature and
it talks just about What user/customer actually needs.
System Requirement Specifications will be prepared From
Business Requirements specifications.
SRS will be more elaborated then the Business requirements.
SRS tell what are system features need to be developed.
After seeing SRS Document Testing People will start 
preparing System Functional Test cases.

After receiving High level Design Doc,Testing people will
prepare the System Integration Test cases.
After seeing Low level Design doc,Development team will will
prepare the Component integration Test cases.
After coding development team will prepare uint test cases
and executes the unit test on the each individual unit or
function.
Thus there is a mapping between the each development  phase
with testing.