How tcpdump command is used to find out the network switch information which is connected to the physical server?

Run the below tcpdump command on physical server.

[root@testserver001 ~]# tcpdump -nn -v -i eth0 -s 1500 -c 1 'ether[20:2] == 0x2000'
tcpdump: WARNING: eth0: no IPv4 address assigned
tcpdump: listening on eth0, link-type EN10MB (Ethernet), capture size 1500 bytes
05:51:39.526913 CDPv2, ttl: 180s, checksum: 692 (unverified), length 434
        Device-ID (0x01), length: 21 bytes: 'TEST01.switch.com'
        Version String (0x05), length: 295 bytes:
          Cisco Internetwork Operating System Software
          IOS (tm) s72033_rp Software (s72033_rp-ADVIPSERVICESK9_WAN-M), Version 12.2(18)SXF17a, RELEASE SOFTWARE (fc1)
          Technical Support: http://www.cisco.com/techsupport
          Copyright (c) 1986-2010 by cisco Systems, Inc.
          Compiled Tue 02-Mar-10 01:50 by tinhuang
        Platform (0x06), length: 16 bytes: 'cisco WS-C6506-E'
        Address (0x02), length: 13 bytes: IPv4 (1) 159.166.128.131
        Port-ID (0x03), length: 16 bytes: 'FastEthernet3/12'
        Capability (0x04), length: 4 bytes: (0x00000029): Router, L2 Switch, IGMP snooping
        VTP Management Domain (0x09), length: 0 byte: ''
1 packets captured
3 packets received by filter
0 packets dropped by kernel