[c-nsp] SNMP descrepancy

[Drew Weaver]

router#sh ip arp vlan 643
Protocol  Address          Age (min)  Hardware Addr   Type   Interface
Internet  10.1.164.46          2   0080.a38c.33d4  ARPA   Vlan643
Internet  10.1.164.41          -   000f.f8a6.6d40  ARPA   Vlan643
Internet  10.1.164.42        146   0030.48bf.3230  ARPA   Vlan643

[root at dev html]# snmpwalk -v2c -c public at 643 192.168.0.1 .1.3.6.1.2.1.17.4.3.1.1
SNMPv2-SMI::mib-2.17.4.3.1.1.0.15.248.166.109.64 = Hex-STRING: 00 0F F8 A6 6D 40 
SNMPv2-SMI::mib-2.17.4.3.1.1.0.128.163.140.51.212 = Hex-STRING: 00 80 A3 8C 33 D4

Does anyone know why I appear to get different data from SNMP than I do from the switch? 

I assume I am doing something moronic and I'm sure you'll prove me right =)

I'm mainly interested in why 10.1.164.42   0030.48bf.3230  is not included in the SNMP output.

-Drew