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NGN Cases
Update Time:
2009-05-27 16:50:08
Views:
4
Author:
q92670
Product Family:
Integrated Access
Fault Type:
Narrow-band Voice Service
Keywords:
Packet loss, dtu
Permission
04Common Users Permission
Level:
Phenomenon De
A UA5000R13C02B032 is deployed under a softswitch. Subscribers often complain that no tone
scription:
is displayed upon off hook.
Alarm Informati
Null
on:
Cause Analysi
1. The network quality is poor.
s:
2. The softswitch does not send the dial tine event correctly.
3. The AG processes H.248 signaling incorrectly.
Handling Proce
1. Send 1000 ping packet from the AG to the softswitch. No packet is lost and the delay is
ss:
stable.
2. Capture packets on the softswitch and the AG simultaneously and compare the signaling
messages.
Signaling captured on the AG:
When the fault occurs, the AG reports offhook and the softswitch sends a dial tone event as
cg/dtu instead of cg/dt. Because cg/dtu is not an H.248 descriptor. The AG cannot identify it and
therefore does not send the dial tone. Because no response is received from the AG, the
softswitch sends five Modify messages to send the dial tone.
Signaling on the softswitch:
The softswitch sends five Modify message continuously to the AG to send the dial tone after a
subscriber hooks off. The dial tone event is cg/dt. Because the AG does not respond, the
softswitch starts the retransmission mechanism and stops sending messages after sending the
message for five times.
But why signaling captured on the softswitch is different from that captured on the AG. On the
AG side, packets are captured by an Ethereal capturer and the dial tone event captured is cg/dtu.
On the softswitch side, packets are captured by the network management application and the
dial tone event captured is cg/dt. Because of modular design, different modules of the softswitch
system accomplish different functions. The signaling capture on the softswitch is signaling of
the protocol processing module. That this signaling is normal does not mean the signaling sent
from the softswitch is normal.
By tracing the Debug message, the softswitch engineer finds that the HSCI is faulty so that error
packets are delivered. Replace the HSCI board. The fault is rectified.
Detailed signaling and analysis are described in the attachment.
Suggestions and
For an inter-product fault (related to the softswitch and the bearer network), it is necessary to
Summary:
capture packets on both sides simultaneously to find which product is faulty.
5.12 FAQ-Voice Subboard Round Robin Mechanism of the PVM Board
Title:
FAQ-Voice Subboard Round Robin Mechanism of the PVM Board
ID:
SE0000392267
Update Time:
2009-05-27 16:50:51
Views:
6
Author:
l92637
Product Family:
Integrated Access
Fault Type:
Narrow-band Voice Service
82
Confidential Information of Huawei. No Spreading without Permission
Chapter 5 UA5000 Narrow-band Service
Product:
UA5000
Product:
UA5000
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