RFC 2089: V2ToV1 Mapping SNMPv2 onto SNMPv1 within a bi-lingual SNMP agent
RFC 2576: Coexistence between Version 1, Version 2, and Version 3 of the Internet-standard Network Management Framework
V2ToV1 Mapping SNMPv2 onto SNMPv1 within a bi-lingual SNMP agent