H.225 / Q.931 Half Packet support (Avaya VoIP Problem

  • Hi All,

    we got a serious problem getting Avaya VoIP Phones to connect to the PBX (Avaya PBX) through a Netscreen<->Netscreen Lan2Lan VPN.

    The Netscreen seem to drop special Acknowledge Packets, which the two members send to the other party.

    The Message we get in the Netscreen debug log:

    RAS packet received ( -> (
    ##2003-05-28 10:59:09 system-debugging: RAS not processed in route or transparent mode.
    ##2003-05-28 10:59:09 system-debugging: Error - Half packet not supported - dropped.
    ##2003-05-28 10:59:09 system-debugging: Error - TPKT out of sync.
    ##2003-05-28 10:59:09 system-debugging:

    When we sniff the normal traffic when both parties are on the same lan, Avaya uses TCP Packets H.255/Q.931 Packets with zero bytes data as Acknowledge packets.

    There is an Avaya Whitepaper available which states how to configure the Netsceen for VoIP Traffic. They use a special untrust-vr router to route the VPN traffic over.

    Is Netscreen handling traffic through a untrust-vr in a different way than the default trust-vr?

    The Firmware versions of the devices:
    Main Site: Netscreen 25, 4.0.3r1
    Remote Site: Netscreen 5XP, 4.0.1r3
    Remote Site2: Netscreen 5XT, 4.0.3r3

    Has anyone solved the problem to connect Avaya IP Hardphones to the PBX over a Netscreen VPN?

    Please help. Its seriously urgent.

    Thanks for your help,


  • I agree with rm89.  With 5.1 they put alot of focus on VoIP support.  4.0 is quite old nowadays.  Only issue I see is with your 5XP.  But at the very least I would upgrade that to the latest in the 5.0 branch.

  • When you say Avaya PBX do you mean the IP Office?  We had an issue connecting the hard phone back to the IP office 403.  What I did was put a static IP on the hard phone and then I created a policy on the netscreen to take the hard phone traffic over the vpn to the network with the IP Office.  In the police select Service H.323 and select Application Ignore.  Did this on the netscreens running 5.1.0r4.  Juniper made many changes regarding QoS and VOIP with Avaya in the 5.1 rev and later.