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eSpace U1930 Failed to Connect a Call When the Calling Number Is Empty

Publication Date:  2015-07-14 Views:  402 Downloads:  0
Issue Description
In one South Africa office where the eSpace U1930 is used, the customer, by analyzing Internet service provider (ISP) call logs, finds that the eSpace U1930 does not perform any operations when receiving INVITE messages with the empty calling number from the ISP. As a result, a large number of similar calls fail to be connected.
Handling Process
This fault occurs because the format of INVITE messages sent by the ISP is invalid. Contact the ISP to correct the format.
Root Cause
Based on the UCMaint logs captured on the eSpace U1930, the eSpace U1930 does not process the INVITE message received from the ISP or return the 100 trying message, resulting in a call connection failure. The INVITE message received by the eSpace U1930 is as follows:

INVITE sip:27117159000@ SIP/2.0 
Via: SIP/2.0/UDP;branch=z9hG4bKanomi9000og1ll042080.1 
P-Asserted-Identity: Anonymous <sip:> 
h323-conf-id: 1434894174-3020831274-3055019666-2148325140 
From: Anonymous <sip:>;tag=h5pbr6kuuu5d2bdg.o 
Content-disposition: session 
Expires: 300 
User-Agent: Sippy 
To: <sip:27117159000@> 
Remote-Party-ID: Anonymous <sip:>;party=calling 
Contact: Anonymous <sip:;transport=udp> 
CSeq: 409 INVITE 
cisco-GUID: 1434894174-3020831274-3055019666-2148325140 
Max-Forwards: 69 
Call-ID: BW115329348210613-518645148@ 
Content-Length: 286 
Content-Type: application/sdp 
o=Sippy 27610256 0 IN IP4 
t=0 0 
m=audio 30086 RTP/AVP 4 18 101 
c=IN IP4 
a=rtpmap:4 G723/8000 
a=rtpmap:18 G729/8000 
a=rtpmap:101 telephone-event/8000 
a=fmtp:101 0-15 
a=fmtp:18 annexb=yes 
a=bsoft: 1

The standard format of an anonymous call is as follows (Anonymous can be replaced by other characters):

From: <sip:Anonymous@;user=phone>;tag=xxx

The actual format of the obtained message, however, is as follows:

From: Anonymous <sip:>;tag=h5pbr6kuuu5d2bdg.o

In the obtained message, the calling party information, which is empty, is not in the standard format. As a result, the eSpace U1930 failed to process the INVITE message and failed to set up the call.