You are here: CSP Developer’s Guide: Internet Protocol > 5 Session-Initiation Protocol (SIP) Software > Report REFER Request URI in PPL Event Indication

Report REFER Request URI in PPL Event Indication

Overview

The REFER message implements a call transfer service.

A user agent (referrer) uses the REFER message to request another user agent (referee) that it is in session-establish state with, to contact a third user agent (refer target).

The Refer target is identified by a SIP URI in the Refer-To header field in the REFER message.

You can enable this feature to get the Request-URI, in the Request-Line of the REFER message, reported to the host.

Example: With a SIP-to-ISDN call, if any ISDN related information like UUI, UUI encoding, or presentation indicator is present as a parameter in the Request-URI, this feature allows the host to get this data.

Pertinent Specification

RFC 3261

Description

This feature enhances the CSP SIP stack to report the Request-URI in the REFER message, including the parameters, to the host. This reporting is a configurable option in the CSP SIP stack and is disabled by default. This feature does not provide write access to Request-URI for a REFER message generated by CSP SIP stack.

Prior to this feature, the CSP SIP could not report the Request-URI in REFER to the host. When this feature is enabled, the Request-URI in the inbound REFER message is reported to the host using the following TLVs within the PPL Event Indication for REFER (Comp: 0x00A7, Event: 0x0021/0x0022 for Blind and Consultative REFER respectively)

• SIP Request URI User Name - 0x2954

• SIP Request URI Password - 0x2946

• SIP Request URI Host Name - 0x2955

• SIP Request URI Port - 0x2956

• SIP Request URI Parameters - 0x2958

• SIP Request URI Headers - 0x2947

Important! All TLVs except the port number TLV ends with a NULL terminator, therefore the actual data supported is one less than the maximum length supported for the TLVs. Also note that the CSP nacks all SIP requests of a size greater that 1500 bytes with the 513 message, Too Large

API Call Control Messages

PPL Event Indication (0x0043)

API and CSA Configuring and Querying

This feature can be configured either using the API or CSA.

API Configuring and Querying

Reporting of Request-URI in the REFER message is a configurable option and is be disabled by default. To enable this reporting, set bit 21 of PPL Event Notification Mask TLV (0x027F) and send it in the VoIP Protocol Configure (0x00EE) message.

CSA Configuring and Querying

To configure and query the SIP stack for this feature, view the Configure SIP Advanced screen, Additional Host Signaling Parameters, and select Report of Request-URI.

Call Flow - Refer Request

The call flow below is a simplified scenario to depict this feature. Assume the CSP is enabled to report Request-URI in inbound REFER to the host. The CSP acts an endpoint, though in most scenarios it acts as a gateway. Once the CSP and UA1 are in session-established state (answered), UA1 puts the session on-hold (Re-INVITE), sends a REFER request to CSP and releases the call. The CSP accepts the Re-INVITE. After the CSP receives the REFER, it responds with the appropriate response (202 in the example) and reports the Request-URI to the host within the PPL Event Indication for the REFER message.

Call Trace - Refer Request

API Trace:

X->H

[01 f2 00 2d 00 0c 01 00 01 0d 03 00 64 0c 00 33 01 03 00 33 01 de 00 1a 27 4e 00 02 00 05 27 7e 00 03 08 00 00 29 19 00 06 31 31 31 31 31 00 29 1b 00 0c 31 30 2e 31 30 2e 31 2e 32 35 30 00 29 1c 00 04 00 00 13 c4 29 23 00 06 32 30 35 39 37 00 29 25 00 0c 31 30 2e 31 30 2e 31 2e 32 35 30 00 29 26 00 04 00 00 13 c4 29 28 00 08 22 53 75 62 62 75 22 00 29 2d 00 06 32 30 35 39 37 00 29 2f 00 0a 31 30 2e 31 30 2e 31 2e 32 00 29 30 00 04 00 00 13 c4 29 33 00 01 01 27 18 00 08 02 00 00 00 05 20 59 70 27 17 00 06 02 00 05 11 11 10 29 16 00 01 01 29 54 00 06 31 31 31 31 31 00 29 55 00 0c 31 30 2e 31 30 2e 31 2e 32 35 30 00 29 56 00 04 00 00 13 c4 29 50 00 36 33 61 30 36 66 61 33 30 66 65 33 30 64 64 34 33 40 63 33 4a 68 61 6d 56 75 5a 48 4a 68 4c 57 6c 69 62 53 35 44 62 33 4a 77 4c 6e 68 73 4c 6d 4e 76 62 51 2e 2e 00 29 51 00 09 33 39 30 65 37 34 30 31 00 29 52 00 09 39 33 36 33 31 31 32 36 00 2a 0e 00 04 0a 0a 01 02 29 9a 00 20 29 9b 00 02 00 22 29 9c 00 16 29 5e 00 0a 31 30 2e 31 30 2e 31 2e 32 00 29 5f 00 04 00 00 13 c4 29 4a 00 04 80 00 00 00 29 ff 00 91 2a 0e 00 04 0a 0a 01 02 2a 01 00 85 2a 03 00 01 00 2a 07 00 04 00 00 20 72 2a 13 00 01 00 2a 02 00 13 2a 08 00 02 00 02 2a 09 00 01 02 2a 0b 00 04 00 00 1f 40 2a 02 00 13 2a 08 00 02 00 01 2a 09 00 01 01 2a 0b 00 04 00 00 1f 40 2a 02 00 13 2a 08 00 02 00 16 2a 09 00 01 16 2a 0b 00 04 00 00 1f 40 2a 02 00 13 2a 08 00 02 00 12 2a 09 00 01 12 2a 0b 00 04 00 00 1f 40 2a 02 00 13 2a 08 00 02 00 17 2a 09 00 01 17 2a 0b 00 04 00 00 1f 40]

H->X

[00 0c 00 2d 00 0c 01 00 01 0d 03 00 64 0c]

H->X

[00 0c 00 2d 00 0c 01 00 01 0d 03 00 64 0c]

H->X

[00 11 00 bf 00 00 01 00 02 0d 03 00 64 0c 0d 03 00 64 0c]

X->H

[00 07 00 bf 00 00 01 00 10]

H->X

[00 0d 00 ba 00 00 01 00 01 0d 03 00 64 0c 01]

X->H

[00 07 00 ba 00 00 01 00 10]

X->H

[00 51 00 43 00 18 01 00 01 0d 03 00 64 0c 00 a7 00 1e 01 03 00 33 00 3b 00 01 29 ff 00 35 2a 0e 00 04 00 00 00 00 2a 01 00 29 2a 03 00 01 00 2a 07 00 04 00 00 20 72 2a 13 00 01 02 2a 02 00 13 2a 08 00 02 00 02 2a 09 00 01 02 2a 0b 00 04 00 00 1f 40]

H->X

[00 05 00 43 00 18 01]

X->H

[00 70 00 43 00 19 01 00 01 0d 03 00 64 0c 00 a7 00 21 01 03 00 33 00 5a 00 08 29 2d 00 06 32 30 35 39 37 00 29 19 00 06 31 32 33 34 35 00 29 1b 00 0c 31 30 2e 31 30 2e 31 2e 32 35 30 00 29 1c 00 04 00 00 13 c4 29 29 00 06 32 30 35 39 37 00 29 54 00 06 31 31 31 31 31 00 29 55 00 0c 31 30 2e 31 30 2e 31 2e 32 35 30 00 29 56 00 04 00 00 13 c4]

H->X

[00 05 00 43 00 19 01]

X->H

[00 57 00 69 00 0c 01 00 01 0d 03 00 64 0c 02 02 1e 2a 00 05 01 04 00 04 00 00 00 00 01 05 00 04 00 00 00 41 01 11 00 04 00 00 01 1c 01 10 00 04 00 00 28 a0 01 12 00 04 00 00 b1 80 03 00 33 00 18 00 03 27 4e 00 02 00 10 27 92 00 04 0a 0a 01 bf 27 93 00 04 00 00 3e c4]

H->X

[00 05 00 69 00 0c 01]

SIP Trace:

1 -RECEIVED From 10.10.1.2:5060 at 4390

INVITE sip:11111@10.10.1.250:5060 SIP/2.0

Via: SIP/2.0/UDP 10.10.1.2:5060;branch=z9hG4bK-d87543-a35cc125786fec3e-1--d87543

-;rport

Max-Forwards: 70

Contact: <sip:20597@10.10.1.2:5060>

To: <sip:11111@10.10.1.250:5060>

From: "Subbu"<sip:20597@10.10.1.250:5060>;tag=390e7401

Call-ID: 3a06fa30fe30dd43@c3JhamVuZHJhLWlibS5Db3JwLnhsLmNvbQ..

CSeq: 1 INVITE

Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY, MESSAGE, SUBSCRIBE, INF

O

Content-Type: application/sdp

Supported: eventlist

User-Agent: eyeBeam release 3010n stamp 19039

Content-Length: 425

v=0

o=- 146862411 146862468 IN IP4 10.10.1.2

s=eyeBeam

c=IN IP4 10.10.1.2

t=0 0

m=audio 8306 RTP/AVP 100 0 8 3 18 98 97 5 101

a=alt:1 1 : EAF29E5C 000000DE 10.10.1.2 8306

a=fmtp:101 0-15

a=rtpmap:100 speex/16000

a=rtpmap:0 pcmu/8000

a=rtpmap:8 pcma/8000

a=rtpmap:3 gsm/8000

a=rtpmap:18 g729/8000

a=rtpmap:98 ilbc/8000

a=rtpmap:97 speex/8000

a=rtpmap:5 dvi4/8000

a=rtpmap:101 telephone-event/8000

a=sendrecv

2 -SENT To 10.10.1.2:5060 at 4390

SIP/2.0 100 Trying

To: <sip:11111@10.10.1.250:5060>;tag=93631126

From: "Subbu"<sip:20597@10.10.1.250:5060>;tag=390e7401

Call-ID: 3a06fa30fe30dd43@c3JhamVuZHJhLWlibS5Db3JwLnhsLmNvbQ..

CSeq: 1 INVITE

Contact: 11111<sip:11111@10.10.1.250:5060>

Via: SIP/2.0/UDP 10.10.1.2:5060;branch=z9hG4bK-d87543-a35cc125786fec3e-1--d87543

-;rport

User-Agent: Excel_CSP/83.10.66

Content-Length: 0

3 -SENT To 10.10.1.2:5060 at 4391

SIP/2.0 180 Ringing

To: <sip:11111@10.10.1.250:5060>;tag=93631126

From: "Subbu"<sip:20597@10.10.1.250:5060>;tag=390e7401

Call-ID: 3a06fa30fe30dd43@c3JhamVuZHJhLWlibS5Db3JwLnhsLmNvbQ..

CSeq: 1 INVITE

Contact: 11111<sip:11111@10.10.1.250:5060>

Via: SIP/2.0/UDP 10.10.1.2:5060;branch=z9hG4bK-d87543-a35cc125786fec3e-1--d87543

-;rport

User-Agent: Excel_CSP/83.10.66

Content-Length: 0

4 -SENT To 10.10.1.2:5060 at 4391

SIP/2.0 200 OK

To: <sip:11111@10.10.1.250:5060>;tag=93631126

From: "Subbu"<sip:20597@10.10.1.250:5060>;tag=390e7401

Call-ID: 3a06fa30fe30dd43@c3JhamVuZHJhLWlibS5Db3JwLnhsLmNvbQ..

CSeq: 1 INVITE

Contact: 11111<sip:11111@10.10.1.250:5060>

Supported: timer

Session-Expires: 1800; refresher=uas

Via: SIP/2.0/UDP 10.10.1.2:5060;branch=z9hG4bK-d87543-a35cc125786fec3e-1--d87543

-;rport

User-Agent: Excel_CSP/83.10.66

Content-Type: application/sdp

Content-Length: 131

v=0

o=sip 1155656630 1155656630 IN IP4 10.10.1.250

s=SIP_Call

c=IN IP4 10.10.1.191

t=0 0

m=audio 16068 RTP/AVP 0

a=sendrecv

5 -RECEIVED From 10.10.1.2:5060 at 4392

ACK sip:11111@10.10.1.250:5060 SIP/2.0

Via: SIP/2.0/UDP 10.10.1.2:5060;branch=z9hG4bK-d87543-7f2675358918741f-1--d87543

-;rport

Max-Forwards: 70

Contact: <sip:20597@10.10.1.2:5060>

To: <sip:11111@10.10.1.250:5060>;tag=93631126

From: "Subbu"<sip:20597@10.10.1.250:5060>;tag=390e7401

Call-ID: 3a06fa30fe30dd43@c3JhamVuZHJhLWlibS5Db3JwLnhsLmNvbQ..

CSeq: 1 ACK

User-Agent: eyeBeam release 3010n stamp 19039

Content-Length: 0

6 -RECEIVED From 10.10.1.2:5060 at 4393

INVITE sip:11111@10.10.1.250:5060 SIP/2.0

Via: SIP/2.0/UDP 10.10.1.2:5060;branch=z9hG4bK-d87543-b6777511fb20a408-1--d87543

-;rport

Max-Forwards: 70

Contact: <sip:20597@10.10.1.2:5060>

To: <sip:11111@10.10.1.250:5060>;tag=93631126

From: "Subbu"<sip:20597@10.10.1.250:5060>;tag=390e7401

Call-ID: 3a06fa30fe30dd43@c3JhamVuZHJhLWlibS5Db3JwLnhsLmNvbQ..

CSeq: 2 INVITE

Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY, MESSAGE, SUBSCRIBE, INF

O

Content-Type: application/sdp

Supported: eventlist

User-Agent: eyeBeam release 3010n stamp 19039

Content-Length: 187

v=0

o=- 146862411 146865057 IN IP4 10.10.1.2

s=eyeBeam

c=IN IP4 0.0.0.0

t=0 0

m=audio 8306 RTP/AVP 0

a=alt:1 1 : EAF29E5C 000000DE 10.10.1.2 8306

a=rtpmap:0 pcmu/8000

a=sendonly

7 -SENT To 10.10.1.2:5060 at 4393

SIP/2.0 100 Trying

To: <sip:11111@10.10.1.250:5060>;tag=93631126

From: "Subbu"<sip:20597@10.10.1.250:5060>;tag=390e7401

Call-ID: 3a06fa30fe30dd43@c3JhamVuZHJhLWlibS5Db3JwLnhsLmNvbQ..

CSeq: 2 INVITE

Contact: 11111<sip:11111@10.10.1.250:5060>

Via: SIP/2.0/UDP 10.10.1.2:5060;branch=z9hG4bK-d87543-b6777511fb20a408-1--d87543

-;rport

User-Agent: Excel_CSP/83.10.66

Content-Length: 0

8 -SENT To 10.10.1.2:5060 at 4393

SIP/2.0 200 OK

To: <sip:11111@10.10.1.250:5060>;tag=93631126

From: "Subbu"<sip:20597@10.10.1.250:5060>;tag=390e7401

Call-ID: 3a06fa30fe30dd43@c3JhamVuZHJhLWlibS5Db3JwLnhsLmNvbQ..

CSeq: 2 INVITE

Contact: 11111<sip:11111@10.10.1.250:5060>

Supported: timer

Session-Expires: 1800; refresher=uas

Via: SIP/2.0/UDP 10.10.1.2:5060;branch=z9hG4bK-d87543-b6777511fb20a408-1--d87543

-;rport

User-Agent: Excel_CSP/83.10.66

Content-Type: application/sdp

Content-Length: 131

v=0

o=sip 1155656630 1155656630 IN IP4 10.10.1.250

s=SIP_Call

c=IN IP4 10.10.1.191

t=0 0

m=audio 16068 RTP/AVP 0

a=sendrecv

9 -RECEIVED From 10.10.1.2:5060 at 4393

ACK sip:11111@10.10.1.250:5060 SIP/2.0

Via: SIP/2.0/UDP 10.10.1.2:5060;branch=z9hG4bK-d87543-316c255f587e511b-1--d87543

-;rport

Max-Forwards: 70

Contact: <sip:20597@10.10.1.2:5060>

To: <sip:11111@10.10.1.250:5060>;tag=93631126

From: "Subbu"<sip:20597@10.10.1.250:5060>;tag=390e7401

Call-ID: 3a06fa30fe30dd43@c3JhamVuZHJhLWlibS5Db3JwLnhsLmNvbQ..

CSeq: 2 ACK

User-Agent: eyeBeam release 3010n stamp 19039

Content-Length: 0

10-RECEIVED From 10.10.1.2:5060 at 4395

11-RECEIVED From 10.10.1.2:5060 at 4396

REFER sip:11111@10.10.1.250:5060 SIP/2.0

Via: SIP/2.0/UDP 10.10.1.2:5060;branch=z9hG4bK-d87543-011a1e4f53392f2d-1--d87543

-;rport

Max-Forwards: 70

Contact: <sip:20597@10.10.1.2:5060>

To: <sip:11111@10.10.1.250:5060>;tag=93631126

From: "Subbu"<sip:20597@10.10.1.250:5060>;tag=390e7401

Call-ID: 3a06fa30fe30dd43@c3JhamVuZHJhLWlibS5Db3JwLnhsLmNvbQ..

CSeq: 3 REFER

User-Agent: eyeBeam release 3010n stamp 19039

Refer-To: <sip:12345@10.10.1.250:5060>

Referred-By: <sip:20597>

Content-Length: 0

12-SENT To 10.10.1.2:5060 at 4396

SIP/2.0 202 Accepted

To: <sip:11111@10.10.1.250:5060>;tag=93631126

From: "Subbu"<sip:20597@10.10.1.250:5060>;tag=390e7401

Call-ID: 3a06fa30fe30dd43@c3JhamVuZHJhLWlibS5Db3JwLnhsLmNvbQ..

CSeq: 3 REFER

Contact: 11111<sip:11111@10.10.1.250:5060>

Via: SIP/2.0/UDP 10.10.1.2:5060;branch=z9hG4bK-d87543-011a1e4f53392f2d-1--d87543

-;rport

User-Agent: Excel_CSP/83.10.66

Content-Length: 0

13-RECEIVED From 10.10.1.2:5060 at 4397

BYE sip:11111@10.10.1.250:5060 SIP/2.0

Via: SIP/2.0/UDP 10.10.1.2:5060;branch=z9hG4bK-d87543-97128e3806547b59-1--d87543

-;rport

Max-Forwards: 70

Contact: <sip:20597@10.10.1.2:5060>

To: <sip:11111@10.10.1.250:5060>;tag=93631126

From: "Subbu"<sip:20597@10.10.1.250:5060>;tag=390e7401

Call-ID: 3a06fa30fe30dd43@c3JhamVuZHJhLWlibS5Db3JwLnhsLmNvbQ..

CSeq: 4 BYE

User-Agent: eyeBeam release 3010n stamp 19039

Content-Length: 0

14-SENT To 10.10.1.2:5060 at 4397

SIP/2.0 200 OK

To: <sip:11111@10.10.1.250:5060>;tag=93631126

From: "Subbu"<sip:20597@10.10.1.250:5060>;tag=390e7401

Call-ID: 3a06fa30fe30dd43@c3JhamVuZHJhLWlibS5Db3JwLnhsLmNvbQ..

CSeq: 4 BYE

Via: SIP/2.0/UDP 10.10.1.2:5060;branch=z9hG4bK-d87543-97128e3806547b59-1--d87543

-;rport

User-Agent: Excel_CSP/83.10.66

Content-Length: 0

Session-Initiation Protocol. A signaling protocol used for establishing sessions in an IP network. A session could be a simple, two-way telephone call, or it could be a collaborative multi-media conference session.
See Integrated Services Digital Network.
See Programmable Protocol Language.
A computer, attached to the Excel platform through an RS-232 or Ethernet link, from which you run the telecommunications application that controls the Excel platform.
The point in the Excel platform where a DS0 connects to a network. Also known as a "socket."
Tag-Length-Value block. A standardized block that allows data to inserted in a standard way into API messages.
Setting up, monitoring, and tearing down calls.
A condition that, when met, drives a state machine from one state to another. A condition that drives a Component out of its current state by invoking an associated primitive.
See Converged Services Administrator.
Voice over Internet Protocol. The delivery of voice information in digital form in discrete packets rather than in the traditional circuit-committed protocols of the public-switched telephone network (PSTN).
Positive acknowledgment to a message
Real-Time Transport Protocol. Supports transport of real-time data like interactive voice and video over packet-switched networks.
In PPL, a condition that, when met, drives a state machine (PPL Component) from one state to another, by invoking an associated Primitive. In PPL files, an Event is marked by an arrow and text.