hello friends,
greetings.
by refering to ASN1.1 standards i understand that following trap
are part of snmpv2-mib ie of oid (1.3.6.1.6)
 1) linkup ( define in IF-MIB ?)
 2) linkdown ( IF-MIB  ?)
 3) coldstart ( SNMPv2-MIB)
 4) warmstart ( SNMPv2-MIB )
 5) authentication failure ( SNMPv2-MIB )                                     

 under this oid node(ie snmpv2-mib ) it has snmptrap defined u can  refer
 to this link for more details
 [ http://www.muonics.com/Docs/MIBSmithy/UserGuide/fmt-oidtree.php ]
 or this for complete view [ http://asn1.elibel.tm.fr/cgi-bin/oid/display?tree=1.3.6.1(2.1,6.3.1.1(4,5  ]
                                                                                                                            
 so looking at this links i observere that linkup, linkdown this trap are part of snmpv2-mib
 still they are define in IF-MIB.txt so question is
 why they are define in this IF-MIB.txt file because this file for interface MIB ?
                                                                                                                            
 one more question ie not related to net-snmp .
 are there any snmp trap defined in MIB-II like coldstart, warmstart(which are defined in snmpv2-mib) ?
 Thanks in advance
 Regards
 bhushan. E . Sonawane