Skip to end of metadata
Go to start of metadata

This section lists the SIP response codes VX sends out and the corresponding Q.850 (ISDN) cause values. VX's default mapping is based on RFC 3398. This section also provides instructions on how to adjust the mappings between SIP and ISDN for differing network conditions. (This section only covers the cause code mappings for the call failures. Successful calls are not covered. This section also does not cover the actual message mapping or mapping features like "Call Hold" or "Suspend and Resume" between SIP and ISDN/ISUP.)

Mapping Q.850 to SIP

The table hows the default RFC3398 mappings of Q.850 to SIP response codes.

ISUP/ISDN (Release) Cause code

SIP Gateway

1 unallocated number

404 Not Found

2 no route to network

404 Not found

3 no route to destination

404 Not found

17 user busy

486 Busy here

18 no user responding

408 Request Timeout

19 no answer from the user

480 Temporarily unavailable

20 subscriber absent

480 Temporarily unavailable

21-usr - call rejected

403 Forbidden (cause location is non user)

21-nonusr - call rejected

603 Decline (cause location is user)

22-nondiag - number changed (w/o diagnostic)

410 Gone

23 redirection to new destination

410 Gone

26 non-selected user clearing

404 Not Found

27 destination out of order

502 Bad Gateway

28 address incomplete

484 Address incomplete

29 facility rejected

501 Not implemented

31 normal unspecified

480 Temporarily unavailable

34 no circuit available

503 Service unavailable

38 network out of order

503 Service unavailable

41 temporary failure

503 Service unavailable

42 switching equipment congestion

503 Service unavailable

47 resource unavailable

503 Service unavailable

55 incoming calls barred within CUG

403 Forbidden

57 bearer capability not authorized

403 Forbidden

58 bearer capability not presently available

503 Service unavailable

65 bearer capability not implemented

488 Not Acceptable Here

70 only restricted digital available

488 Not Acceptable Here

79 service or option not implemented

501 Not implemented

87 user not member of CUG

403 Forbidden

88 incompatible destination

503 Service unavailable

102 recovery of timer expiry

504 Gateway timeout

111 protocol error

500 Server internal error

127 inter-working unspecified

500 Server internal error

Default (any other)

500 Server internal error

Adjusting the SIP-to-Q.850 Cause Code Mapping

VXbuilder has two items in the Telephony branch of Directory tree so you can use to adjust the mapping of cause codes. These two items are:

  • SIP to Q.850 Cause codes
  • Q.850 to SIP Cause codes

To adjust SIP-to-Q.850 cause code mappings, access the SIP-to-Q.850 Cause Code Table in VXbuilder by selecting the Telephony-> SIP to Q.850 Cause Code Tables links in the VXbuilder Directory tree.

The VXbuilder interface only shows exceptions from the standard RFC3398 mappings. The default mappings are not shown. You can view these via the command line interface.

When you use the UC wizard, additional configurations that are unique to OCS are added. These include:

  • Q.850 cause code "88 - incompatible destination" is mapped to SIP response code "400 - Bad Request".
  • SIP response code "487 Request Terminated" maps is mapped to Q.850 cause code "127 -Internet working unspecified".

VXbuilder with Cause Code Table Entries

SIP-to-Q850 Cause Codes

When you select one of the SIP response codes, the SIP-to-Q.850 cause code mapping dialog appears which allows you to map the selected SIP response code to any of the Q.850 cause codes listed. (It is also possible to map multiple SIP response codes to same Q.850 cause code.)


SIP to Q.850 Cause Code Mapping Dialog

;

Q.850-to-SIP Cause Codes

Similarly when you select any of the Q.850 cause codes, the Q.85- to-SIP cause code mapping dialog displays. It is also possible to map multiple Q.850 cause codes to a single SIP response code.


SIP to Q.850 Cause Code Mapping Dialog

;

Command Line Interface

Command line interface has two commands show maptablesip-Q850 and show maptableQ850-sip to show the mappings between SIP and Q.850 cause codes.

show maptable sip-Q850 Command

This command outputs all the default mappings between SIP response codes and the Q.850 cause code values (per RFC3398). When the user configures any mapping, the default mapping is replaced with the exception and is denoted by "<>" in the output display.

Show maptable sip-Q850 output

show maptable Q850-sip Command

This command lists all the default mappings between Q.850 cause codes to SIP response codes (per RFC3398). As mentioned above, when you configure any mapping, the default mapping is replaced with the exception and is denoted by "<>" in the output display.

Show maptable sip-Q850 output

Q.850 Cause Code Interworking

It is also possible that same SIP/Q.850 code gets mapped to different Q.850/SIP codes. In this case, during transmit/config verify, a warning message will display saying that the SIP/Q.850 cause code is already mapped to a Q.850/SIP code and the latest selection will overwrite all previous mappings.

The Q.850 cause code mapping selections allow you to choose the same cause code based on the location or other deciding factors. VX allows you to choose 21-nonusr-call rejected (location - nonusr) if the location is non user and 21-user-call rejected (location-usr) if the location is user. Similarly 22 - nondiag -Number changed (without diagnostic) will be used to select the cause code without diagnostic option.

  • No labels