CDP: 3550 sending hello to 2950.

For a week I have not touched my switches, thanks to a new game which I’ve got… Playing game is a waste of time…zzzzz

Today I started practising with a MLS and a switch, switch receive cdp updates from MLS, but MLS did not receive updates from switch.

I turn on debug cdp events and debug cdp adjaceny, no outputs…. zzz

Anyway later I have found that the switch port has non-negotiate turned on and my MLS port connecting to this switch port was configured as dynamic desirable. This means switch refused MLS port’s request to negotiate a trunk… lol… great…. so i think if not a trunk then the port should be an access port.

Anyway in my MLS port i hardcode the port as a trunk, before that I type this command:
3550-2(config-if)#switchport trunk encapsulation dot1q

cat3550 supports ISL as well as 802.1q. After I have set MLS port manually to trunk, MLS receives cdp updates from 2950 switch.. great…

CDP-EV: CDP sending protocol-hello notification
CDP-EV: protocol-hello notification, contents:
CDP-EV: notification_count = 1
CDP-EV: OUI =0x00000C, Protocol ID=0x0112
CDP-EV: payload len=27, value=00000000FFFFFFFF010221FF00000000000000169D055080FF0000
CDP-EV: receiving IDB name = ‘FastEthernet0/1’
CDP-EV: remote device name = ‘2950-1’, CDP device number = 1
CDP-EV: remote interface name = ‘FastEthernet0/1’
CDP-EV: src_mac = 0016.9D05.5081, capabilities = 28
CDP-EV: duplex = 3, native-vlan = 100
CDP-EV: received_vtp_mgmt_domain = 1, vtp_mgmt_domain_length = 5
CDP-EV: vtp-management-domain-name = ‘cyrus’