Hi,
GET VPN uses time-based anti-replay (TBAR), which is
based on a pseudo-time clock that is maintained on the KS. An advantage of using pseudotime for
TBAR is that there is no need to synchronize time on all the GET VPN devices using NTP.
http://www.cisco.com/c/dam/en/us/products/collateral/security/group-encrypted-transport-vpn/GETVPN_DIG_version_1_0_External.pdf
Regards,
Rahul chhabra
Network Engineer
Spooster IT Services