(IMS 8.2) CSCF Internal Message Trace Guide

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Internal Message Trace Guide - Training Slide 2011-03-25

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After completing this course, you will understand:  CSCF architecture: internal module (PID) and its functions  PIDs through which the basic message processing flow passes  Procedure of locating problems by using internal messages  Typical cases about locating problems by using internal messages

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Chapter 1 CSCF Architecture: Internal Module (PID) and Its Functions Chapter 2 Functions of the PIDs in the Basic Message Flow Chapter 3 Procedure of Locating Problems by Using Internal Messages Chapter 4 Typical Cases

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Chapter 1 CSCF Architecture: Internal Module (PID) and Its Functions 1.1 CSCF Architecture 1.2 Processes of the CSCF NE and Their Functions 1.3 Diagrams of the Application Layers of the P-CSCF, I-CSCF, and S-CSCF NEs 1.4 Main PID Functions of Different Processes

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1.1 CSCF Architecture Call Session Control Function (CSCF) 

Based on locations and functions, CSCFs can be classified into three types: P-CSCF, S-CSCF, and I-CSCF: 



P-CSCF (Proxy CSCF): As the first interaction point between the IMS network and users, the P-CSCF provides the proxy function. That is, the P-CSCF accepts and forwards service requests but cannot modify the Request URI field in an INVITE message. The P-CSCF also provides the user agent (UA) function, that is, interrupting and independently generating SIP sessions when a fault occurs.  S-CSCF (Serving CSCF): As the core of the IMS core network, the S-CSCF performs the registration authentication, session control of UEs, and the implements the basic session routing functions for the IMS users on the calling side and called side. In addition, based on the IMS triggering rules to which the user have subscribed, the S-CSCF triggers value-added service routes to ASs and completes service control interaction when the conditions are met.  I-CSCF (Interrogating CSCF): Similar to a gateway node on the IMS network, the I-CSCF allocates service nodes to the users in the current domain, queries routes, and hides topologies between IMS domains. The P-CSCF, S-CSCF, and I-CSCF can be physically integrated. In the actual networking, factors such as the IMS service access mode, positions of IMS access points, CSCF capacities and capabilities, and user traffic requirements, need to be considered for the division and deployment of CSCFs. The network topology hiding and interconnection requirements of the operator also need to be considered.

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1.1 CSCF Architecture Processing on

Processing on

Processing on

Processing on

Processing on

the P-CSCF

the S-CSCF

the I-CSCF

the BCF

the MRFC

Protocol processing and

...

message distribution

Protocol processing and message distribution

IPv4 and IPv6 packet distribution and processing

IP Core

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1.1 CSCF Architecture 

IPv4 and IPv6 packet distribution and processing layer:  Provides the function of converging multiple IP addresses.  Supports the IPv4 and IPv6 dual-stack  Distributes IP packets according to the quintuple (source IP address, destination IP address, source port number, destination port number, and protocol ID) or IPSec SA.



Protocol processing and message distribution layer:  Supports network layer processing, for example, IPSec processing.  Supports the processing of transport layer protocols, such as the SCTP, TCP, and UDP.  Supports the coding and decoding in the DNS/ENUM, Diameter, and COPS protocols.  Supports the upward distribution and downward forwarding of protocol messages.



Application processing layer:  Supports the coding and decoding of SIP messages and transaction-layer processing of protocols.  Completes the application processing on the P-CSCF, I-CSCF, S-CSCF, and BCF.

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Chapter 1 CSCF Architecture: Internal Module (PID) and Its Functions 1.1 CSCF Architecture 1.2 Processes of the CSCF NE and Their Functions 1.3 Diagrams of the Application Layers of the P-CSCF, I-CSCF, and S-CSCF NEs 1.4 Main PID Functions of Different Processes

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1.2 Processes of the CSCF NE and Their Functions 

Functions of the processes:



Dispatch Unit (DPU): As the system egress, the DPU receives IP packets from external systems and forwards the IP packets to the corresponding BSU and out of the system.



Broadband Signaling Unit (BSU): As the signaling processing process, the BSU terminates TCP/SCTP connections, completes the coding and decoding in the COPS and Diameter protocols, and converts the coded and decoded messages into internal messages before forwarding the messages to the SCU and ASU.



Session Control Unit (SCU): As the call control process, the SCU completes functions such as SIP processing, DIAMETER coding/decoding and protocol processing, call connection and service triggering, service logic control, and charging. The SCU and ASU complete the service logic functions of the P-CSCF, I-CSCF, S-CSCF, BCF, MRFC, and GT-AS.



Central Database (CDB): As the central database process, the CDB maintains the global data and user distribution data in the system.

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1.2 Processes of the CSCF NE and Their Functions  As a global database, the CDB centrally controls the distribution.

CDB (central database)

SCU (service processing)

BSU (protocol processing)

SCU (service processing)

BSU (protocol processing)

DPU (IP packet distribution)

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 The SCU completes the secondary distribution of SIP signaling and service processing.

BSU (protocol processing)

 The DPU distributes IP messages, including UDP messages and connection-oriented messages, to the BSU and SCU.

DPU kernel

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 The BSU establishes, manages, and deletes connection-oriented links, including the TCP links carrying SIP signaling.

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Chapter 1 CSCF Architecture: Internal Module (PID) and Its Functions 1.1 CSCF Architecture 1.2 Processes of the CSCF NE and Their Functions 1.3 Diagrams of the Application Layers of the P-CSCF, I-CSCF, and S-CSCF NEs 1.4 Main PID Functions of Different Processes

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Related Tasks on the Application Layer of the P-CSCF P registration processing

P session processing

P user data management

P P/IM processing

P subscription processing

Charging

SIPCB

QoS

NAT

SCU P user index management

SIP transaction layer

DIAMETER RM

SIP distribution COPS

DNS

SIP TPT, CODEC COMPRESS, IPSec

DPU

DIAMETER distribution DIAMETER CM

UDP/IP

TCP/IP

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Related Tasks on the Application Layer of the I-CSCF Processing on the I-CSCF

SIPCB

SCU

Charging

DIAMETER RM

SIP transaction layer

DIAMETER distribution

SIP distribution DNS SIP TPT, CODEC UDP/IP

DIAMETER CM TCP/IP

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Cx/Dx

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Related Tasks on the Application Layer of the S-CSCF S registration processing

S calling party processing

S called party processing

S ILCM

S OLCM

S subscription data management

SCU S user index management

SP/IM processing

S subscription processing

Charging

SIPCB

Cx/Dx

ENUM transaction DIAMETER RM

SIP transaction layer

SIP distribution DNS/ENUM SIP TP, CODEC

CDB

DIAMETER distribution DIAMETER CM

UDP/IP

TCP/IP

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Chapter 1 CSCF Architecture: Internal Module (PID) and Its Functions 1.1 CSCF Architecture 1.2 Processes of the CSCF NE and Their Functions 1.3 Diagrams of the Application Layers of the P-CSCF, I-CSCF, and S-CSCF NEs 1.4 Main PID Functions of Different Processes

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1.4 Main PID Functions of Different Processes 

PID-SIPC: It is the SIPC module and the adaptation layer of the SIP protocol stack. All the SIP messages, for example, the request and response messages exchanged between the PReg module and the SIPC module, are reported by the PID-SIPC to the service layer.



PID-DBMS: Queries the configuration and static configuration related to user access.



PID-PREG: Module that the P-CSCF uses to process the registration flow



PID-IMSG: Service processing module of the I-CSCF



PID-PCALL: Module that the P-CSCF uses to process the call flow



PID-SCALL: Module that the S-CSCF uses to process the call flow



PID-DiamRM: Diameter protocol stack



PID-MRC: Internal processing control module of the MRC



PID-CRO: Module responsibility or H.248 processing and distribution

Remarks: PID: In this document, a PID refers to the sub-module of a process (module). A PID is the basic unit used for message communication. For example, the PREG, PCALL, SREG, and SCALL are the sub-modules of the SCU process. MID: It indicates the module ID. In this document, the internal message trace mainly involves the SCU and CDB processes.

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Chapter 1 CSCF Architecture: Internal Module (PID) and Its Functions Chapter 2 Functions of the PIDs in the Basic Message Flow Chapter 3 Procedure of Locating Problems by Using Internal Messages Chapter 4 Typical Cases

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Chapter 2 Functions of the PIDs in the Basic Message Flow 2.1 Internal Message Format 2.2 Registration Process 2.3 Basic Call Flow 2.4 Flow of Tone Playing and Number Receiving on the MRFC

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2.1 Internal Message Format User message trace information:

Column No.

Content

Meaning

1

NO

Message sequence number It indicates the sequence in which the message is generated (In the case of network delay, a message sent later may arrive beforehand).

2

Time Stamp

Timestamp It indicates the message generation time, which is the same as the host time.

3

Source Address

It indicates the source IP address of the message and has a value only for an external (inter-NE) message.

4

Source port

It indicates the source port number of the message and has a value only for an external (inter-NE) message.

5

Destination Address

It indicates the destination IP address of the message and has a value only for an external (inter-NE) message.

6

Destination port

It indicates the destination port number of the message and has a value only for an external (inter-NE) message.

7

Message Interface Type

Message interface type: Indicates the message that module A sends to module B. For example, TRC_MI_SIPC_P indicates the message that the SIPC sends to the PREG and PCALL. CSCF_TRACE_MI_PREG_SIPC indicates the message that the PREG sends to the SIPC.

8

Message Type

Message type name For example, SIG_TRACE_MSG_INVITE_REQ indicates the INVITE message that the SIPC sends to the PCALL. CSCF_TRACE_MSG_ANID_QUERY indicates the message that the PREG sends to the DBMS to query the access network ID.

9

Hex Message

Hexadecimal code stream data of the message

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2.1 Internal Message Format Focus on the messages in the first eight columns:

Message interface type: Specifies whether the message is between two modules (PIDs) or between NEs. For example: TRC_MI_SIPC_P: Indicates a message sent by the SIPC to the PREG and PCALL. CSCF_TRACE_MI_IMSG_DBMS: Indicates a message sent by the IMSG to the DBMS for data query. Remarks: On the message trace interface, Diameter messages and SIP messages are identified in different colors. Message Type: Describes the type of the message. For example: CSCF_TRACE_MSG_AN_INFO_QUERY: Indicates a request message that the PREG and PCALL send to the DBMS to query the access network information. CSCF_TRACE_MSG_DIAM_USER_AUTHORIZATION: Indicates a message that the IMSG sends to the DIAMRM to query the user registration status.

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Examples of Inter-NE Message Interface Types 

SIP-based message interface type: TRC_MI_SIPC_UP, TRC_MI_SIPC_DOWN: external message interaction between a UE and P-CSCF TRC_MI_SIPC_SHORT: external message interaction among the P-CSCF, I-CSCF, and S-CSCF



DIAMETER-based message interface type: TRC_MI_DIAM_CXDX_ACCT: external message interaction among the I-CSCF, S-CSCF, and HSS based on the Cx and Dx interfaces, including message types such as UAR, UAA, MAR, MAA, SAR, SAA, LIR, and LIA TRC_MI_DIAM_GQ: external message interaction among the P-CSCF, BCF, and PDF based on the Gq interface, including message types such as the AAR, AAA, STR, and STA



H.248-based message interface type: BCCOMP_TRACE_MI_H248_MGW: interaction of the external messages that the P-CSCF and BCF send to the MGW based on the Ia interface, including message types, such as the ADD_REQ, MOD_REQ, SUB_REQ, and NTFY_REQ BCCOMP_TRACE_MI_MGW_H248: interaction of the external messages that the MGW sends to the P-CSCF and BCF based on the Ia interface, including message types, such as the ADD_REPLY, MOD_REPLY, SUB_REPLY, and NTFY_REPLY

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Chapter 2 Functions of the PIDs in the Basic Message Flow 2.1 Internal Message Format 2.2 Registration Process 2.3 Basic Call Flow 2.4 Flow of Tone Playing and Number Receiving on the MRFC

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2.2 Registration Process Caller UE

P-CSCF

1.REGISTER

DNS

I-CSCF

S-CSCF

HSS

2.DNS Query 3.DNS Query Resp 4. REGISTER

5. Diameter: UAR 6. Diameter: UAA 7.REGISTER 8.Diameter: MAR 10. 401 Unauthorized

11. 401 Unauthorized

12. 401 Unauthorized 13.REGISTER

9.Diameter: MAA

14.DNS Query 15.DNS Query Resp 16. REGISTER

17. Diameter: UAR 18. Diameter: UAA 19.REGISTER

23. 200 OK

22. 200 OK

20.Diameter: SAR 21.Diameter: SAA AS

24. 200 OK 25.REGISTER 26. 200 OK

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Example of the Interaction Between PIDs in the Registration Flow SIPC

PREG

DBMS

IMSG

SREG

1.REGISTER(req) 2.DBMS_QUERY(req) 3.DBMS_QUERY(rsp) 4.REGISTER(rsp) 5.REGISTER(req) 6.DBMS_QUERY(req) 7.DBMS_QUERY(rsp) 8.REGISTER(rsp)

9.REGISTER(req) 10.DBMS_QUERY(req) 11.DBMS_QUERY(rsp) 12.REGISTER(rsp)

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PIDs in the Registration Flow 

PID-SIPC: It is the SIPC module and the adaptation layer of the SIP protocol stack. All the SIP messages, for example, the request and response messages exchanged between the PReg module and the SIPC module, are reported by the PID-SIPC to the service layer.



PID-PREG: Module that the P-CSCF uses to process the registration flow



PID-SREG: Module that the S-CSCF uses to process the registration flow



PID-IMSG: Service processing module of the I-CSCF



PID-PSDB: This module stores the dynamic data of users, including the P user data. The PReg module interacts with this module to create, query, update, and delete user data.



PID-BILL: This module is used for charging.



PID-NAT: This module is used by the PReg module to update the users after NAT translation or create NAT mappings.



PID-DiamRM: This module is used by the PReg module to query the location information about fixed users, instruct the CLF to release the user subscription, and process the IP information release request messages reported by the CLF.



PID-PSA: This module is used by the PReg module to exchange SA-related information with the PSDB, including creating, querying, deleting, and updating SAs.



PID-HTMAIL: This module is used by the PReg module to query the location information about fixed users by using HTMAIL.



PID-LI: This module is used to support monitoring, including the functions such as obtaining the monitoring handle and sending monitoring reports.



PID-DBMS: Queries the configuration and P static configuration related to user access.

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Chapter 2 Functions of the PIDs in the Basic Message Flow 2.1 Internal Message Format 2.2 Registration Process 2.3 Basic Call Flow 2.4 Flow of Tone Playing and Number Receiving on the MRFC

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2.3 Basic Call Flow Caller UE

P-CSCF INVITE

S-CSCF

I-CSCF

S-CSCF

P-CSCF

Callee UE

INVITE INVITE

INVITE INVITE INVITE

INVITE183

INVITE183

INVITE183

INVITE183

INVITE183

INVITE183

PRACK PRACK PRACK

PRACK200

PRACK200

INVITE180 INVITE180

INVITE180 INVITE200 ACK BYE

PRACK PRACK200

PRACK200

PRACK200

INVITE180

PRACK

INVITE180 INVITE200

INVITE180 INVITE200

INVITE200 INVITE200

INVITE200 ACK BYE

ACK

ACK

BYE

ACK

BYE BYE BYE200

BYE200

BYE200

BYE200 BYE200

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PIDs in the Basic Call Flow 

PID-SIPC: It is the SIPC module and the adaptation layer of the SIP protocol stack. All the SIP messages, for example, the request and response messages exchanged between the PReg module and the SIPC module, are reported by the PID-SIPC to the service layer.



PID-DBMS: Data management module used to query static databases.



PID-PCALL: Module that the P-CSCF uses to process the call flow



PID-SCALL: Module that the S-CSCF uses to process the call flow



PID-IMSG: Service processing module of the I-CSCF



PID-PSDB, SSDB: This module stores user dynamic data, including the P user data.



PID-BILL: This module is used for charging.



PID-NAT: This module is used by the Pcall module to update the users after NAT translation or create NAT mappings.



PID-DiamRM: Diameter protocol stack



PID-PSA: This module manages SA data.



PID-LI: This module is used to support monitoring, including the functions such as obtaining the monitoring handle and sending monitoring reports.



PID-DBMS: Queries the configuration information and P static configuration related to user access.

Message capture:

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Chapter 2 Functions of the PIDs in the Basic Message Flow 2.1 Internal Message Format 2.2 Registration Process 2.3 Basic Call Flow 2.4 Flow of Tone Playing and Number Receiving on the MRFC

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2.4 Flow of Tone Playing and Number Receiving on the MRFC The MP interface is an H.248 interface. On the Mr interface, the tone playing and number receiving functions can be implemented according to the MSML standards .

PID_SIPC

AS

R1: INVITE(S1) R2: 100

PID_MRC

R3: INVITE_REQ R4: FEED_BACK

CDB::PID_DBMS

R15: INFO

R11: INVITE_2XX_RSP

MRFP

R5: APPLY_REQ R6: APPLY_RSP

R7: PREPARE-BEARER-REQ

R12: 200 OK R13: ACK

PID_CRO

R10: PREPARE-BEARER-RSP

R8: ADD_REQ R9:ADD_RLY

R14: ACK_REQ

R16: INFO_REQ R17: INFO_RSP

R18: PLAY-MEDIA-REQ

R19: 200 OK

R22: PLAY-MEDIA-RSP

R25: MEDIA-COMPLETED-IND R26: STOP-MEDIA-REQ

R29: STOP-MEDIA-RSP

R20: MOD_REQ R21: MOD_REPLY R23: NTFY_REQ R24: NTFY_REPLY

R27: : MOD_REQ R28: MOD_REPLY

R30: DETECT-DTMF-REQ

R31: MOD_REQ R32: MOD_REPLY R33: DETECT-DTMF-RSP

R36: REPORT-DTMF-IND

R34: NTFY_REQ R35: NTFY_REPLY

R37: STOP-DTMF-DETECT-REQ

R40: STOP-DTMF-DETECT-RSP

R42: INFO R43: 200 OK R45: BYE

R38: MOD_REQ R39: MOD_REPLY

R41: INFO-REQ

R44: INFO-RSP

R46: BYE-REQ R47: BYE-RSP R48: REL-SIPC-REQ

R51: 200 OK

R49: DB-MRFPRELEASE-REQ R50: RELEASE-TERM-REQ R53: DB-MRFPRELEASE-RSP

R55: RELEASE-TERM-RSP

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R52: SUB_REQ R54: SUB_REPLY

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PIDs in the Flow of Tone Playing and Number Receiving on the MRFC 

AS: service NE



PID-SIPC: SIP protocol stack



PID-MRC: internal processing control module of the MRC



CDB::PID-DBMS: multimedia center data module on the CDB



PID-CRO: module responsible or H.248 processing and distribution



MRFP: multimedia resource processing module

Message capture:

MRFC·ÅÒôÊÕºÅÁ÷³Ì

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Chapter 1 CSCF Architecture: Internal Module (PID) and Its Functions Chapter 2 Functions of the PIDs in the Basic Message Flow Chapter 3 Procedure of Locating Problems by Using Internal Messages Chapter 4 Typical Cases

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Chapter 3 Procedure of Locating Problems by Using Internal Messages 3.1 Warning Header Field 3.2 Procedure of Locating Problems

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3.1 Warning Header Field The following describes the structure of the warning header field by using two examples: Example 1: Warning: 399 0154601493.P.huawei.com.204.020.011.0000361D "Fail to validate the user“ Structure analysis: Item

Value

Description

Attention Required or Not

File name

01546

PID_PCALL_PCALLSIP, specifically pcallsip.c

Internal information that does not require attention

Line No.

1493

Line 943 of pcallsip.c

Internal information that does not require attention

CSCF host name

P.huawei.com

Host name of the configured P-CSCF

Attention required

PID name

204

It refers to PID_PCALL. Find out the PID corresponding to the PID name. Then, locate the problem based on the PID function.

Attention required

Module number

011

It corresponds to the SCU module No. The module No. can be displayed on the Module Management interface on the OMU client.

Attention required

Error cause

0000361d

It refers to the failure to compare the received SIP message from the access side with the contact address specified during the registration.

Internal information that does not require attention

Fail to validate the user

The contents enclosed within quotation marks "" are the error information. Currently, most errors are represented by Server internal error, which provides no information about the error. A user can find out the error only after querying codes. This problem needs to be solved.

Attention required

Error description

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3.1 Warning Header Field Example 2: Warning: 399 154.12.17.1 "SS010006F06580L00289[0000] No Response From Network“ After a message is sent, if no response is received within the timeout time, the protocol stack reports an error response to inform the service NE of the timeout.

Structure analysis: Item

Value

Description

Attention Required or Not

CSCF address

154.12.17.1

Address of the service NE to which the protocol stack sends the error response

Attention required

Code line No.

SS010006F06580L00289[0000

Position of the code for the protocol stack to report the error

Internal information that does not require attention

No Response From Network

It refers to no response from the peer network. Generally, the cause is that the address carried in the sent message is incorrect.

Attention required

Error description

The following attachment summarizes the release points of the CSCF service processing:

F:\IMSÖúÊÖ\ CSCFÒµÎñ´¦ÀíÊͷŵã»ã×Ü.rar

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Chapter 3 Procedure of Locating Problems by Using Internal Messages 3.1 Warning Header Field 3.2 Procedure of Locating Problems

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3.2 Procedure of Locating Problems Step 1: Capture internal traced messages. Generally, if the registration and call flow fails, an important method of locating problems is user message trace. Remarks: For details about capturing user trace message, see section 2.1 in CSC3300 V100R006C03 Internal Message Trace Guide.doc. This document does not detail the message capture procedure. In addition, during the capture of user message trace when a problem occurs, it is recommended to select the Log option so that certain user data information is recorded.

Step 2: Based on the contents in the Warning header field, check which NE sends the error response. According to the message flows before and after the error response is returned, locate the message that the NE receives before sending the failure response. Then, according to the main functions of the NEs in the flow, infer the possible causes of the release.

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3.2 Procedure of Locating Problems Step 3: Analyze the contents of the release message. Focus on the information such as the release status code and release cause description. As shown in the following message and log output, the PID_IMSG fails to query the HSS address.

Step 4: Based on the functions of the PID and release cause prompt text, analyze the possible causes. Generally, possible causes can be classified into the following types: 1. The system configuration is incorrect. Incorrect system configuration causes basic call and number analysis flow failures. In this case, check whether the related data configuration is correct, for example, whether the link is Up. Check whether the terminal is connected to a correct access network. 2. The user is not defined. The user information carried in the SIP message that the user sends for registration is inconsistent with the user definition information on the HSS. 3. The message does not conform to the protocol specifications. For example, the media negotiation does not conform to the protocol specifications and a mandatory header field is missing. In this case, in addition to checking whether the processing on the CSCFs is correct, analyze whether the messages sent by the terminals and other NEs are correct. Step 5: Based on the analysis result obtained in Step 4, check the related configuration. Remarks: If the cause of the problem fails to be located after careful configuration check by performing the preceding procedure, save the internal trace messages and contact the R&D personnel for locating the problem.

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Chapter 1 CSCF Architecture: Internal Module (PID) and Its Functions Chapter 2 Functions of the PIDs in the Basic Message Flow Chapter 3 Procedure of Locating Problems by Using Internal Messages Chapter 4 Typical Cases

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Chapter 4 Typical Cases 4.1 Typical Problems in the Registration Flow 4.2 Typical Problems in the Call Flow

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4.1 Typical Problems in the Registration Flow Symptom

Possible Cause

Troubleshooting

Key Parameter Line

Key Parameter

The I-CSCF returns a 500 response during registration.

The peer HSS of the I-CSCF is faulty.

Check the traced messages. Check whether the I-CSCF sends any UAR. If not, check whether the IHSSL link is Up.

Lines 47 and 57

ulErrorCode in line 47 and Warning in line 57

The P-CSCF returns a 403 response during registration.

The P-CSCF fails to query the PACN table.

Check the traced messages between the Preg and DBMS. Check whether the PACN query is successful. If not, check whether the IP address of the terminal belongs to the network segment configured on the PACN.

Lines 11 and 22

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ulErrorCode in line 11 and Warning in line 22

Message Capture

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4.1 Typical Problems in the Registration Flow Symptom

Possible Cause

Troubleshooting

Key Parameter Line

Key Parameter

The S-CSCF returns a 403 response during registration.

During the registration, the P-CSCF fails to set the integrity-protected field to Yes. Therefore, the SCSCF considers the registration request as invalid.

Check whether access security is configured in the access network security policy of the PACN.

Lines 6, 173, and 189

integrityprotected, PACN Warning in line ÖнÓÈë²à°²È«²ßÂÔÅäÖôíÎó,×¢²áS»Ø40 189, and ucAccessSecuri ty in line 6

During registration, the protocol stack reports a 408 timeout response.

The P-CSCF, I-CSCF, or S-CSCF fails to locate the nexthop route or locates an incorrect route.

Check whether the DNSSRV and DNSRESA are configured correctly.

Lines 28, 29, 30, 31, and 56

Warning in line 56 and ulIpAddress in line 31

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Message Capture

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Chapter 4 Typical Cases 4.1 Typical Problems in the Registration Flow 4.2 Typical Problems in the Call Flow

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4.2 Typical Problems in the Call Flow Symptom

Possible Cause

Troubleshooting

Key Parameter Line

Key Parameter

During the call flow, the PCSCF returns a 403 message.

The Contact address used during the registration carries Userinfo, whereas the Contact address in the INVITE message of the call does not carry Userinfo. According to the PACN configuration, however, users need to be differentiated according to Userinfo. As a result, the PCSCF fails to query the user data.

If the P-CSCF fails to query the user data, check whether the query keyword and the user keyword saved during the registration are different. If the Userinfo information is different, check whether the PACN table is configured to differentiate users according to Userinfo.

Lines 210, 228, 233, and 254

acPIpDispatchKey in line 210, ulErrorCode and acPDispatchKey in ×¢²áʱCONTACTµØ line 233, and Ö·ÀïЯ´øUSRINFO£¬µ«INVITEÎ ucAccessSecurity in line 228

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Message Capture

4.2 Typical Problems in the Call Flow Symptom

Possible Causes

Troubleshooting

Key Parameter Line

Key Parameter

During the call flow, the calling S-CSCF returns a 404 message.

The calling S-CSCF fails to locate the called I-CSCF. A possible cause is that the called number is a TEL number and number analysis is not configured.

Check the number type of the called number in the INVITE message. If the number type is TEL, check whether the SNRTANA, SRTADDR, and SRTANA configuration is correct.

Lines 336, 337, and 357

Warning in line 357 and tEnumRspRe cord in line 337

During the bearer control flow, the PCSCF returns a 500 message.

The PADA configuration or PLNI configuration of the access network on which the user resides is incorrect.

Run command LST PLNI to check whether the local domain network attribute is configured. Then, check whether the P-CSCF queries the PDF device successfully. If not, run command LST PADA to check whether the PDF device is attached to the correct access network.

Lines 179 and 215

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Message Capture

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ulErrorCode in line 179 and Warning in line 215

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