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CCNA Recap: Hot Standby Routing Protocol (HSRP)






https://www.cisco.com/c/en/us/td/docs/switches/datacenter/sw/5_x/nx-os/unicast/configuration/guide/l3_cli_nxos/l3_hsrp.html

Redundance | Load Balancing 
for ipv4
hosts

default priority for standby routers are 100

Virtual Router Redundancy Protocol is the non cisco proprietary version of HSRP
—————  HSRP ——————


Cisco proprietary
Group # 0 - 255, int. signif only.
  • v. 2 expands to 4095 groups
  • v . 2 uses 224.0.0.102 multicast ipv4
    • ipv6 multicast is FF02::66

224.0.0.2 is multicast address for v. 1

standby preempt to force a new election


last eight bits of the Virtual Mac = standby group
priority range 0 - 255, default 100
hello timer def. 3 sec, holddown, 10 sec.
preempt is not enabled by default
‘cisco’ for default auth
u can use MD5 ( - v.2)
active router election; Highest priority wins, highest IP if a tie
  • v.2 mac range 0000.0C9F.F000 to 0000.0C9F.FFFF (Ipv4)
  • v2. mac range 0005.73A0. 0000 -  0005.73A0.0FFF for ipv6 
Fasted router to boot becomes the active one, irregardless of config. priority, if there is no preempt configured
——— hot standby ————————

Virtual Router: “I’m not in active or standby, I’m just listening and knowing infnormation.” 

In standby, you’re a candidate to be the active router


  • Spanning tree priority = lower = better
  • HSRP priority = higher = better

Consider legacy routing protocols

————— Configuration ————
First Router 
int ____
ip add [add][mask]
standby version 2 

standby [group #] ip [default gateway / virtual router IP]
must match on each router involved.

standby [group #] priority [up to 250 I believe? Higher = better]
standby [group #] preempt forcing election 
no shut

Second Router 

int ____
ip add [add][mask]
standby version 2 

standby [group #] ip [default gateway / virtual router IP] 
must match on each router involved.

no shut


EMPLOYERS: This shows that I review material I have tested and passed to refresh myself.
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