Traps sent by VCS are reversible to SNMPv2 after an SNMPv2 to SNMPv1 conversion.

For reversible translations between SNMPv1 and SNMPv2 trap PDUs, the second-last ID of the SNMP trap OID must be zero. This ensures that once you make a forward translation (SNMPv2 trap to SNMPv1; RFC 2576 Section 3.2), the reverse translation (SNMPv1 trap to SNMPv2 trap; RFC 2576 Section 3.1) is accurate.

The VCS notifier follows this guideline by using OIDs with second-last ID as zero, enabling reversible translations.