Hello,
In normal Redundancy the redundant procesor has the same configuration of the active processor.
In case of a failover the redundat processor is brought online, and all the Layer 2 and Layer 3 information has to be rebuild.
When you are using SSO redundancy, the time of interrupcion is minimal because protocol and session information for Layer 2 and Layer 3 connections are maintained.
SSO maintain the following information:
- Link negotiation
- Vlan, VTP, trunks, DTP, STP
- UDLD
- SPAN, RSPAN
- 802.1x
- Port Security
- Traffic Storm Control
- L2TP
- Inline Power
- LACP, PAgP
- MAC move notification
- ARP
- Diagnostic
- Securoty and IP Phone Stage
- FIB and adjacency table
- QoS Policies and ACLs
- MAC address tables
The time for a switchover in normal redundancy is between 30 seconds to 4 minutes.
The time for a switchover with SSO is between 0-3 seconds.
Hope this information help,
Osvaldo U.
