eSpace 6805 IP Phone
Administrator Guide
6 Appendix
Issue 01 (2014-01-06)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
139
Figure 6-60
Transport control layer of the SIP protocol
At the transport control layer, check whether:
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The destination port is correct.
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The application process port is correct.
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The checksum information is correct.
The network adapters of certain devices may calculate the checksum of the User
Datagram Protocol (UDP) layer. If the checksum is incorrect, the network adapter of
the device may discard the packet.
Application layer
The fifth layer in the protocol layer description window is the application layer, which
contains the SIP protocol details.
The signaling record consists of Request-Line and Message Header. If a message
includes a message body, Message Body is also included, as shown in
Figure 6-61
Request messages at the application layer of the SIP protocol
The message header information can be used to locate faults, as shown in