check the following link
http://www.allinterview.com/showanswers/118

EQUIVALENCE CLASS PARTITION : THIS IS A TECHNIQUE USED IN 
THE BLACK BOX TESTING METHOD, USED TO REFINE THE DATA INTO 
VALID AND INVALID CLASSES 
 FOR EXAMPLE : A TEXT BOX ACCEPTS ONLY ALPHABETS THEN CHECK 
WITH VALID : ENTRING a-z,A-Z THEN WITH INVALID :!@&* AND 
SPACES,12 ETC

BOUNDARY VALUE ANALYSIS: THIS IS A TECHNIQUE USED IN THE 
BLACK BOX TESTING METHOD,USE TO CHECK THROUGH RANGE TO 
MINIMIZE THE TIME , RATHER THAN TESTING WITH WHOLE DATA
FOR EXAMPLE :(1-1000)
HERE NO NEED OF TESTING RIGHT FROM START IE FROM 1 TO 100 
INSTEAD, CHECK WITH THE VALUES 0,1,2,99,100,101

ecp is amethod by which we can deferentiate the test cases
into valid and invalid
where as in bva we have the 3 classes
1)min and maximum
2)min-1& max+1
3)min+1&max-1

ECP:here we will partition the input data into various valid
and invalid subclass
BVA:we will check the input datarange with max and min values.

Equalance partion is a method of black box testing.for eg 
if the application is accept the values between 10 to 50.we 
are giving  valid and invalid inputs to the system and 
check the status.
  eg inputs valid:25,30
            invalid:9,60
boundary value analyses also method of blackbox testing.in 
this case we r taking boundary vaues for eg in abouve eg 
upper boundary value is 50,and lower boundary value is 10.
               inputs
                     upper boundary 49,51.
                     lower boundary 9,11
                      on boundary   10,50

Equivalence partitioning is the test case developed to
identify the maximum possible bugs, to ensure the
application is defect less.

Boundary value analysis is the test case to optimize the
Equivalence Partitioning. ie limit the number of inputs,
such that the application is behaving as expected.

in equalance class partion, we divide the test data into 
subsets of classes.
Example: 
Scanario
1-500
TEST CASES
1)<1     should invalid
2)>500     should invalid
3)in between 1-500     valid

iN BOUNDARY VALUE
WE WILL CHECK 0,1
AND 500,501

The main difference between EP and BVA is that EP 
determines the number of test cases to be generated for a 
given scenario where as BVA will determine the effectivenss 
of those generated test cases.

Equivalence partitioning :

Equivalence Partitioning determines the number of test 
cases for a given scenario.

Equivalence partitioning is a black box testing technique 
with the following goal:
1.To reduce the number of test cases to a necessary 
minimum. 
2.To select the right test cases to cover all possible 
scenarios. 
EV is applied to the inputs of a tested component. The 
equivalence partitions are usually derived from the 
specification of the component's behaviour. 

An input has certain ranges which are valid and other 
ranges which are invalid. This may be best explained at the 
following example of a function which has the pass 
parameter "month" of a date. The valid range for the month 
is 1 to 12, standing for January to December. This valid 
range is called a partition. In this example there are two 
further partitions of invalid ranges. The first invalid 
partition would be <= 0 and the second invalid partition 
would be >= 13.

... -2 -1  0   1 .............. 12     13  14  15 ..... 
      -------  --------------------   -----------------
 invalid 
partition 1     valid partition       invalid partition 2

The testing theory related to equivalence partitioning says 
that only one test case of each partition is needed to 
evaluate the behaviour of the program for the related 
partition. In other words it is sufficient to select one 
test case out of each partition to check the behaviour of 
the program. To use more or even all test cases of a 
partition will not find new faults in the program. The 
values within one partition are considered to 
be "equivalent". Thus the number of test cases can be 
reduced considerably.
Equivalence partitioning is no stand alone method to 
determine test cases. It has to be supplemented by boundary 
value analysis. Having determined the partitions of 
possible inputs the method of boundary value analysis has 
to be applied to select the most effective test cases out 
of these partitions.

Boundary Value Analysis :

Boundary Value Analysis determines the effectiveness of 
test cases for a given scenario.
To set up boundary value analysis test cases the tester 
first has to determine which boundaries are at the 
interface of a software component. This has to be done by 
applying the equivalence partitioning technique. Boundary 
value analysis and equivalence partitioning are inevitably 
linked together.
For the example of the month a date would have the 
following partitions:
        ... -2 -1  0 1 .............. 12 13  14  15 ..... 
      --------------|-------------------|-------------------
--
 invalid partition 1     valid partition    invalid 
partition 2
By applying boundary value analysis we can select a test 
case at each side of the boundary between two partitions . 
In the above example this would be 0 and 1 for the lower 
boundary as well as 12 and 13 for the upper boundary. Each 
of these pairs consists of a "clean" and a "dirty" test 
case. 
A "clean" test case should give a valid operation result of 
the program. A "dirty" test case should lead to a correct 
and specified input error treatment such as the limiting of 
values, the usage of a substitute value, or in case of a 
program with a user interface, it has to lead to warning 
and request to enter correct data. 
The boundary value analysis can have 6 test cases: n, n-1, 
and n+1 for the upper limit; and n, n-1, and n+1 for the 
lower limit.

1)Rather than selecting any element in an equi. class as
being, boundary - value analysis requires that one or more
elements be selected such that each edge of the equivalence
class 
2)boundary val depends more on input test condition whereas
equi value test cases depend more on output classes