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MSAN UA5000 Cases
2.7
Pause Point in the Program Caused by the Loss of the UDP Fragment in the Multicast
Service of the Smart MA5600T
Pause Point in the Program Caused by the Loss of the UDP Fragment in the
Title:
Multicast Service of the Smart MA5600T
ID: SE0000337594
Information
Troubleshooting Cases
Type :
Update Time: 2008-07-15 17:19:22
Views: 14
Author: y69494
Product Family: Broadband Access
Fault Type: BTV Service
Keywords: UDP fragment BTV
Permission
04Common Users Permission
Level:
Phenomenon De
Version:
scription:
V800R005C32B056
Networking:
Multicast-sever------Cisco SW ------ MA5600T ------ xdsl-board ------ modem ------STB
------TV
|--------- other-produce----xdsl-board---- the same modem ------STB ----TV
Description:
The multicast service is normal, but the picture quality of the program is a little poorer
than that of the competitor and the program has pause point. In addition, the comparison
between the packets captured by the two PCs that are in the place of the two clients
shows that the third fragment of some UDP packets captured by the PC connected to
the MA5600T is discarded. See the attachment for the packet capturing file.
Alarm Informatio
Null
n:
Cause Analysi
1. The packet capturing file in the feedback from the filed engineer shows that the third
s:
fragment of some UDP packets captured on the client in a certain period is discarded.
Surely, this is the cause of the pause point and what is next is to find out the location in
which this fragment is discarded.
2. Capture packets respectively in three locations of the topology:
①Capture packets on the egress port of Cisco and perform the port mirroring on the
Cisco device. Check the sequence of the packets transmitted from the upper layer
device, analyze the packets (about 10 M) captured from the Cisco router, and find that
the problem of discarded fragment does not occur. Only some multicast UDP packets
with fewer bytes are found , which is not the problem.
②Perform the egress port mirroring on our LSW. Mirror the packets that are transmitted
to the service board to the GIU port and capture packets.
MA5600T(diagnose)%%debugging lswdrv bcm-cli
BCM.0> _Mirror mode=add OutPort=8 ToPort=6
8===>This refers to the egress direction of this GE port on the LSW. The 8GE port maps
the service board in slot 1
6===>This is to mirror the packet in the egress direction of port 8 to this GE port of the
LSW. The 6GE port maps port 0/20/0 of this uplink board.
Analyze the captured packets (14 M) of the LSW and find that only the fragments of
some two-frame packets are discarded; however, the number of discarded fragments is
very small and this problem may occur only in the case of the multicast server burst.
③Use the PC to capture packets on the modem of our service board and find that the
symptom is the same as that in the feedback. The third fragment of many multicast UDP
packets is discarded. We are sure that the fragment is discarded by either the board or
the modem.
Confidential Information of Huawei. No Spreading without Permission
Chapter 2 MA5600T (IP DSLAM) Cases
Quality Level:
B
Product: MA5600T MSAN
31
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