Extension Mobility Login is Unavailable (23)

Posted by
Facebooktwitterredditpinterestlinkedintumblr

Issue: Cisco 7821 SIP IP Phone intermittently login to Extension Mobility service. Error displayed on the phone was Login is Unavailable (23).

Platform:
Cisco 7821 SIP IP Phone running on firmware version 10.1(1)SR1
Cisco Unified Communications Manager version 10.5.1.10000-7

Time        Source                Destination           Protocol Length Info
0.000000    192.168.60.69        192.168.101.242       TCP      70     51493 > http-alt [SYN] Seq=0 Win=14480 Len=0 MSS=1460 TSval=195791 TSecr=619720525
0.000095    192.168.101.242       192.168.60.69        TCP      70     http-alt > 51493 [SYN, ACK] Seq=0 Ack=1 Win=14480 Len=0 MSS=1460 TSval=619767712 TSecr=195791
0.000686    192.168.60.69        192.168.101.242       TCP      66     51493 > http-alt [ACK] Seq=1 Ack=1 Win=14480 Len=0 TSval=195791 TSecr=619767712
0.006832    192.168.60.69        192.168.101.242       HTTP     510    GET /emapp/EMAppServlet?device=SEP00082F1B6653 HTTP/1.1 
0.006880    192.168.101.242       192.168.60.69        TCP      66     http-alt > 51493 [ACK] Seq=1 Ack=445 Win=15544 Len=0 TSval=619767719 TSecr=195792
0.062434    192.168.101.242       192.168.60.69        HTTP/XML 814    HTTP/1.1 200 OK 
0.063115    192.168.60.69        192.168.101.242       TCP      66     51493 > http-alt [ACK] Seq=445 Ack=749 Win=15708 Len=0 TSval=195797 TSecr=619767774
0.065465    192.168.60.69        192.168.101.242       TCP      66     51493 > http-alt [FIN, ACK] Seq=445 Ack=749 Win=15708 Len=0 TSval=195797 TSecr=619767774
0.065564    192.168.101.242       192.168.60.69        TCP      66     http-alt > 51493 [FIN, ACK] Seq=749 Ack=446 Win=15544 Len=0 TSval=619767777 TSecr=195797
0.065973    192.168.60.69        192.168.101.242       TCP      66     51493 > http-alt [ACK] Seq=446 Ack=750 Win=15708 Len=0 TSval=195798 TSecr=619767777
10.020709   192.168.60.69        192.168.101.242       TCP      70     51494 > http-alt [SYN] Seq=0 Win=14480 Len=0 MSS=1460 TSval=196793 TSecr=619767777
10.020821   192.168.101.242       192.168.60.69        TCP      70     http-alt > 51494 [SYN, ACK] Seq=0 Ack=1 Win=14480 Len=0 MSS=1460 TSval=619777733 TSecr=196793
10.021377   192.168.60.69        192.168.101.242       TCP      66     51494 > http-alt [ACK] Seq=1 Ack=1 Win=14480 Len=0 TSval=196793 TSecr=619777733
10.026852   192.168.60.69        192.168.101.242       HTTP     534    GET /emapp/EMAppServlet?device=SEP00082F1B6653&seq=35600&userid=35600 HTTP/1.1 
10.026900   192.168.101.242       192.168.60.69        TCP      66     http-alt > 51494 [ACK] Seq=1 Ack=469 Win=15544 Len=0 TSval=619777739 TSecr=196794
10.166359   192.168.101.242       192.168.60.69        HTTP/XML 576    HTTP/1.1 200 OK 
10.167019   192.168.60.69        192.168.101.242       TCP      66     51494 > http-alt [ACK] Seq=469 Ack=511 Win=15544 Len=0 TSval=196808 TSecr=619777878
10.176926   192.168.60.69        192.168.101.242       TCP      66     51494 > http-alt [FIN, ACK] Seq=469 Ack=511 Win=15544 Len=0 TSval=196809 TSecr=619777878
10.177023   192.168.101.242       192.168.60.69        TCP      66     http-alt > 51494 [FIN, ACK] Seq=511 Ack=470 Win=15544 Len=0 TSval=619777889 TSecr=196809
10.177447   192.168.60.69        192.168.101.242       TCP      66     51494 > http-alt [ACK] Seq=470 Ack=512 Win=15544 Len=0 TSval=196809 TSecr=619777889

Hypertext Transfer Protocol
    GET /emapp/EMAppServlet?device=SEP00082F1B6653&seq=35600&userid=switch HTTP/1.1\r\n
        [Expert Info (Chat/Sequence): GET /emapp/EMAppServlet?device=SEP00082F1B6653&seq=35600&userid=switch HTTP/1.1\r\n]
            [Message: GET /emapp/EMAppServlet?device=SEP00082F1B6653&seq=35600&userid=switch HTTP/1.1\r\n]
            [Severity level: Chat]
            [Group: Sequence]
        Request Method: GET
        Request URI: /emapp/EMAppServlet?device=SEP00082F1B6653&seq=35600&userid=35600
        Request Version: HTTP/1.1
    Host: 192.168.101.242:8080\r\n
    Accept: x-CiscoIPPhone/Menu, x-CiscoIPPhone/Text,  x-CiscoIPPhone/IconMenu, x-CiscoIPPhone/IconFileMenu, x-CiscoIPPhone/Directory, x-CiscoIPPhone/Input, x-CiscoIPPhone/Execute, text/*, */*\r\n
    Accept-Language: en_GB\r\n
    Accept-Charset: utf-8,iso-8859-1;q=0.8\r\n
    x-CiscoIPPhoneModelName: CP-7821\r\n
    x-CiscoIPPhoneSDKVersion: 8.5.1\r\n
    x-CiscoIPPhoneDisplay: 396,133,1,G\r\n
    \r\n
    [Full request URI: http://192.168.101.242:8080/emapp/EMAppServlet?device=SEP00082F1B6653&seq=35600&userid=35600]
    [HTTP request 1/1]
    [Response in frame: 16]

Solution: Logging in to Cisco 7821 IP Phone via Extension Mobility was a hit and miss. Some phones worked okay after phone reboot and others didn’t. I took a packet capture on the Cisco Unified Communications Manager side, it showed the user ID and PIN passed were received correctly, user ID and PIN were 35600. Didn’t have a chance to get the Cisco Unified Communications Manager logs as I knew this kind of behaviour was a bug either on the phone or server side. I started to search over Cisco bug database and found this bug ID CSCuo99592 (problem description: 7841 Intermittently will not login to Extension Mobility). The bug ID I found was relevant to Cisco 7841 SIP IP phone but very close enough as they were in the same phone series. I went back to Cisco 7821 download page, guess what? A new firmware just released, version 10.2(1). I read the release notes but no mention of Extension Mobility bug fixed, however I still downloaded the firmware and installed it to three test phones. Tried to login and all login attempts were successful. Added more phones in my test setup, still I could login without any hiccups. Finally, I upgraded all the phones firmware to 10.2(1).