IT Certification and Training Blog

First Hop Redundancy Protocol (FHRP)

Posted by Kelson Lawrence on Dec 19, 2014 10:12:00 AM

Differences between HSRP, VRRP, and GLBP — A Quick Reference

By Brian Scheibe

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HSRP

VRRP

GLBP

Preempt (Default)

Disabled

Enabled

Disabled1/Enabled2

Virtual MAC Address

One shared

One shared

Four distributed3

Virtual MAC Address Format

0000.0C07.ACxy4

0000.5e00.01xx5

0007.b400.xxyy6

Active Device Election 1

Highest priority

Virtual IP address matches interface7

Highest priority/Weighting8

Active Device Election 2

Highest IP address9

Highest priority

Highest IP address9

Active Device Election 3

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Highest IP address9

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RFC(s)

2281 – Cisco-proprietary

5798

None – Cisco-proprietary

IPv4 Multicast Address

v1 224.0.0.2 / v2 224.1.1.102

224.0.0.18

224.0.0.102

Text Authentication Max Characters

8

8

255

MD5 Key-String Authentication Max Characters

64

64

100

Router States

1 Active / 1 Standby / all others Listen10

1 Master / all others Backup10

1 Active / 1 Standby / all others Listen10

Maximum Active Forwarders

1

1

4

 

1 GLBP – Active virtual gateway (AVG) - disabled

2 GLBP – Active virtual forwarder (AVF) – enabled

3 GLBP – Each of up to four AVFs will be assigned a unique virtual media access control (MAC) address by the AVG6

4 HSRP – Where xy is the HSRP group number in hexadecimal based on the respective interface

5 VRRP – Where xx is the virtual group number in hexadecimal

6 GLBP – Where xx is the GLBP group number and yy is the AVF number in hexadecimal

7 VRRP – The device that has a VRRP virtual IP address that matches the physical interface’s IP address will always be the Active router, regardless of preemption or priority

8 GLBP – AVG determined by highest priority / AVF determined by load balancing type configuration and weighting

9 Highest IP address on the physical interface, not the virtual IP address

10 List of states for each FHRP type:



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HSRP

VRRP

GLBP11

Initial

x

x

x

Learn

x

----

---- 

Speak

x

x

x

Listen

x

x

x

Disabled

x

x

x

Active

x

---- 

x

Master

----

x

----

Standby

x

---- 

x

Backup

---- 

x

----

 

11 GLBP – Forwarders only support four states: Disabled, Initial, Listen, Active

 

Tags: Brian Scheibe, VRRP, quick reference, Differences between HSRP, and GLBP, guide