<Jeremy's IT Lab> Day 29: FHRP(First Hop Redundancy Protocols)

FHRP(First Hop Redundancy Protocols)

 

 

https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipapp_fhrp/configuration/xe-16/fhp-xe-16-book/fhp-hsrp-mgo.html

 

-> prob: clinet can't determine which router they have to send

-> sol: FHRP

- Active/ Standby elected

- Virtual IP/ MAC gererated

- end-host use VIP/ VMAC as their communication

  (process)

    - PC request ARP

    - Active router replies ARP with virtual MAC

    - if Active router fails, standby router send gratuitous ARP so switch update MAC adrs table

    * previous active router doesn't take back automatically (can config 'preemption')

 

* gratuitous ARP: ARP replies without being requested

* active router priority:

 (1) highest priority

 (2) highest IP adrs

 

 

FHRP	Terminology	Mulicast IP	Virtual MAC	Cisco proprietary	config
HSRP	Active/Standby	v1: 224.0.0.2 v2: 224.0.0.102	v1: 0000.0c07.acXX v2: 0000.0c9f.fXXX	Y	single router with single VLAN or subnet
VRRP	Master/Backup	224.0.0.18	0000.5e00.01XX	N	single router with single VLAN or subnet
GLBP	AVG/AVF	225.0.0.102	0007.b400.XXYY (X= GLBP group#, Y= AVF #)	Y	multi router with single VLAN or subnet

AVG (Ative Virtual Gateway)

AVF (Active Virtual Forwardings)