HSRP Question

[afo99]

Hi guys,

I am doing practice questions to make sure what i have learnt is enough for my ccnp switch exam, and i may be wrong in this one.

But from what i learnt in HSRP v1, that the the last 2 hexi decimal is the HSRP group
And in one of the questions it mentions:

"Which virtual MAC address does HSRP group 37 USE with default configuration?
A. 00:00:c:07ac:25
B. 00:00:c:07ac:37
C. 00:00:c:37:00:00
D. 00:00:c:25:00:00
Answer: A"

Now i am confused as to why the answer is A and not B.
Please advise 

Thanks

[acampbell]

Hi AFO99,

The mac address numbers are in hex. But HSRP groups are defined in Decimal.

so Decimal HSRP group 37 = 25Hex

37/16 = 2R5 = 25Hex.

"A" is correct

[Ankt Tiwari]

hi afo99,

As you know that HSRP uses this virtual MAC address, 0000.0C07.ACxy, where xy is the HSRP group number in hexadecimal.

so your HSRP group no is 37 which is in a decimal format so we need to change it into hexadecimal

37 = 0010 0101 binary

0010 0101 = 25 hex

so by this process, for HSRP Group 37 the  Mac address will be : 00:00:c:07ac:25