Which OSI layer does HSRP , VRRP and GLBP operate and why?

[joshiaroon]

Dear Expert

I want to know which OSI layer does HSRP , VRRP and glbp operates ? In one of my techincal interview , they told me hsrp and glbp operate in layer 2 and vrrp operate in layer 3. Just want to confirm

Thanks in Advance

AJ

[cadet alain]

Hi,

hsrp and glbp are using udp whereas vrrp is using its own transport protocol so what you were told at the interview is false.

Regards.

Alain.

[Latchum Naidu]

Hi,

HSRP works on layer 3 and provides a standby IP address for hosts on that network to use as their gateway

And GLBP is a little different and runs on layer 2. Instead of one router taking all the traffic all the time, GLBP provides a mechanism to load-balance the standby IP. I’m sure you figured that out by the name, though. When configured, GLBP provides a standby IP just as HSRP does, but it also provides multiple virtual MAC addresses.

Please click on the correct answer on all posts if they answered your question.
Regards,
Naidu.

[davy.timmermans]

I would say for all:  L2 and L3

A mechanism for default gateway redundancy (L3) via an underlying mechanism at Layer2 (virtual MAC).

[burleyman]

Couldn't you make the argument that HSRP "Operates" at Layer 4. Layer 4 is described that it "Manages connections and provides reliable packet delivery. Operates in units of messages."  HSRP sends hello messages and they are used to communicate between router in the HSRP group. So wouldn't that indicate HSRP "operates" at layer 4?

Mike

[er.vansh17091]

Hi Team,

As per my knowledge, HSRP and VRRP work on Layer 3 and GLBP works on layer 2.

And all of these work on UDP.

HSRP-UDP-1985

VRRP -UDP -112

GLBP-UDP-3222