u have to define 4 cases 2 for valid class & 2 for invalid
class, like if u have user name max 6 char for that u have
to enter 1.Blank 2.one char 3.six char. 4.seven char that is
boundary value analysis.

in above answer use 2 & 4 for BVA 
& for equivalence use all 1 to 4 step.

Boundary value analasys:
Let the upper limit and Lower limits be N and M for a 
system then 
N-1, N , N+1 , M-1, M and M+1are considered as inputs for 
Boundary value

Equivalent partitioning :
When N amd M are lower and upper limits of a system the 
Equivalent partitioning includes "N. M and any input 
between "N and M".

Boundary Analysis- This is a black box test design tech. In 
boundry analysis tester will test the software at tha edges 
of the equivalence partition. Idea is to assume if software 
work perfectly at the edges it will work properly else 
where. e.g. if a text field accepts value between 0-100 
boundry value test should include values as lower limit-1 
i.e. -1 & valid value anything between 0 to 100 & Upper 
limit +1. Boundry value analysis is used to reduce the 
redundancy in test cases.

Equivalence Partition- This is a blk box test design tech. 
in which the whole input domain is divided in to few no of 
logical partitions. These logical partitions are termed as 
Equivalence Partitions. It is assumed that all values in a 
partition are supposed to have same system responce.
e.g. if a text field accepts value between 0-100 then 
according to eqv Partition less than 0 is one partition, 0-
100 will be second partition & more than 100 will be third 
partition. Equivalence partitioning  is used to reduce the 
redundancy in test cases.