我通过以下方式使用Windupm来获取本机VLAN信息：
WinDump.exe -nn -v -i \Device\NPF_{55C9305C-C681-49FB-8604-1A7XXXXXXXX} -s 1500 -c 1 "ether[20:2] == 0x2000"
我确实获得了CDP软件包，但是VLAN信息不存在。
17:49:31.191283 CDPv2, ttl: 180s, checksum: 692 (unverified), length 443
Device-ID (0x01), length: 34 bytes: 'switch.example.com'
Version String (0x05), length: 264 bytes:
Cisco IOS Software, Catalyst 4500 L3 Switch Software (cat4500e-IPBASEK9-M)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2011 by Cisco Systems, Inc.
Compiled Thu 27-Jan-11 12:19 by prod_rel_team
Platform (0x06), length: 15 bytes: 'cisco WS-C4900M'
Address (0x02), length: 13 bytes: IPv4 (1) switch.example.com
Port-ID (0x03), length: 18 bytes: 'GigabitEthernet0/1'
Capability (0x04), length: 4 bytes: (0x00000029): Router, L2 Switch, IGMP snooping
Prefixes (0x07), length: 5 bytes: IPv4 Prefixes (1): 10.0.0.0/20
VTP Management Domain (0x09), length: 0 byte: ''
当我使用的CISCO CDP Monitor（https://www.tallsoft.com/cdpmonitor.htm）在后面使用Windump ...时，它显示VLAN正确性。
可能是什么问题？我如何获得完整的CPD？