ExtremeSwitching (EXOS)

  • 1.  Aastra VOIP phone and ELRP

    Posted 06-23-2016 19:44
    Hi All,

    We are currently struggling with an issue which appears to exist between our Extreme edge switches and certain models of VoIP phones.

    Basically, despite having ELRP configured, if a user creates a loop by plugging both the PC and LAN ports on the back of a phone into the same switch the switch does not detect it.

    We have carried out packet captures. With a laptop plugged directly into the switch, we see the ELRP packets every 2 seconds. If we put one of these phones in between (with the laptop plugged into the phones PC port) the ELRP packets do not arrive.

    This suggests that the phones are stripping/filtering the packets in some way.

    Any suggestions are welcome.

    Thank you,
    Mykhaylo


  • 2.  RE: Aastra VOIP phone and ELRP

    Posted 06-23-2016 20:09
    Do you use a separate VLAN for voice and data? if so, do you have the elrp client configured for both VLANs on the port?


  • 3.  RE: Aastra VOIP phone and ELRP

    Posted 06-23-2016 20:09
    One of our senior engineers was doing troubleshooting in the lab. Results below:

    As you could see from our tests in your lab , the other phones tested with ELRP operated as expected as does a direct cable loop ( using Loop vlan with all ports tagged ).

    It is only the old phones 4422 that present this unexpected behaviour.

    As we have already discussed ELRP uses a Multicast packet.. It would appear that the version of phone at your site , block these packets.

    So we have basically 2 answers from an Extreme hardware point of view:

    1:
    The 4422 version of phone are being replaced, if so you could priorities those units that are connected to Extreme edge switches .

    2:
    Configure a basic STP configuration which as demonstrated will block the port ( led still active ) when a loop is detected .
    SH STPD S0 detail , active port will be forwarding , other (looped ) port is shown as Blocked.

    Thank you all for your input on this,

    Mykhaylo


  • 4.  RE: Aastra VOIP phone and ELRP

    Posted 06-23-2016 20:15
    Was going to suggest the same as Matthew. ELRP is associated with one or more VLAN's.



  • 5.  RE: Aastra VOIP phone and ELRP

    Posted 06-24-2016 05:35
    Storm control (flood rate-limit) would help. ('disable port' option is available in 16.1 or later)

    # configure ports rate-limit flood broadcast out-actions disable-port


  • 6.  RE: Aastra VOIP phone and ELRP

    Posted 06-24-2016 09:30
    Hi Matthew,

    Just to confirm that this configuration works fine with Aastra 6731i model.

    Only Aastra 4425 or 4422 are affected.

    enable elrp-client
    configure elrp-client periodic B37 ports 1:1-46, 2:1-3, 2:5-40, 2:42-48, 3:1-46, 4:1-48, 5:1-5, 5:7-48 interval 2 log-and-trap disable-port duration 30
    configure elrp-client periodic B37_VOIP ports 1:1-46, 2:1-3, 2:5-40, 2:42-48, 3:1-46, 4:1-48, 5:1-5, 5:7-48 interval 2 log-and-trap disable-port duration 30

    Cheers,
    Mykhaylo