What are the default HSRP Hello and Hold timers, and what are the recommended minimum values?
The default HSRP (Hot Standby Router Protocol) Hello timer is 3 seconds and the Hold timer is 10 seconds. Don't set Hello below 1 second or Hold below 4 seconds to avoid instability.
Timer details:
| Timer | Default | Purpose | Minimum Recommended |
|---|---|---|---|
| Hello | 3 seconds | Interval between Hello messages sent by active and standby routers | 1 second |
| Hold | 10 seconds | How long the standby waits without a Hello before declaring the active router dead | 4 seconds |
Relationship: The hold timer should always be at least 3× the hello timer. If hellos arrive every 3 seconds, and you wait 10 seconds → you tolerate missing ~3 hellos before declaring failure.
Tuning trade-offs:
- Lower timers → faster failover but more CPU usage, more bandwidth for Hellos, and risk of false failovers (a brief network congestion could cause a missed Hello)
- Higher timers → slower failover but more stable, less overhead
Configuration:
Router(config-if)# standby 1 timers 1 4 ! Hello=1s, Hold=4s
Router(config-if)# standby 1 timers msec 200 msec 700 ! Sub-second timers
With default timers: Failover takes approximately 10 seconds — the standby must wait the full hold time before assuming the active role.
With tuned timers (1s/4s): Failover takes approximately 4 seconds — significantly faster, suitable for environments where sub-10-second failover is important (e.g., VoIP).