You are here: CSP Developer’s Guide: Internet Protocol > 5 Session-Initiation Protocol (SIP) Software > SIP Referred By Mechanism

SIP Referred By Mechanism

Overview

This feature supports the insecure refer technique using the Referred-By mechanism. This mechanism supports Call Agent Mode (CAM) and non-CAM configurations. The Referred-By header is disabled by default.

There are applications of the REFER where it is desirable to provide the refer target with the information about the referrer. The refer target can use this information when deciding whether to admit the referenced request. This feature provides the refer target with the SIP URI of the referrer.

Pertinent Specification

RFC 3892

Description

This feature allows the host to instruct the CSP SIP stack to insert the Referred-By header in the outbound REFER request. By default the CSP SIP stack does not include the Referred-By header. The Referred-By header is then reported to the host by the CSP receiving the REFER request (Referee) within the PPL Event Indication to report receipt of REFER message.

The host can use this Referred-By header data in either the Outseize Control (0x002C) or Route Control (0x00E8) message to instruct the CSP SIP stack to include Referred-By header in the INVITE request to the Refer Target (another CSP). The Refer target reports the Referred-By header in the INVITE to the host with in the RFS.

API Messages Used

• PPL Event Request (0x0044)

• PPL Event Indication (0x0043)

• Outseize Control (0x002C)

• Route Control (0x00E8)

• Request For Service with Data (0x002D)

These messages support the following TLVs.

• 0x2929 - SIP Referred By Header URI TLV

• 0x292A - SIP Referred By Header Parameters TLV

API and CSA Configuring and Querying

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

API Configuring and Querying

By default CSP does not report the Referred-By header, if it is present in the received REFER request or INVITE request message. To enable this feature, set bit 18 in the 0x027F - SIP Message Information Mask TLV and send it within the VoIP Protocol Configure (0x00EE) message.

See 0x027F - SIP Message Information Mask TLV

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 Referred by Header in Refer and Invite.

Call Flow - Insecure Refer

The call flow below shows the insecure Refer scenario.

Notes

• The call flow assumes that Referrer and Referee are in answered state.

• All CSPs have the Referred-By header reporting enabled.

• The PPL ER for REFER to Referrer instructs CSP SIP stack to include Referred-By mechanism in the REFER request.

• The referee receiving the REFER request reports the Referred-by header to the host in the PPL Event Indication used to report the receipt of REFER message.

• The host uses this Referred-By header data received in the PPL Event Indication, within the Outseize Control message to instruct the CSP SIP stack to include the Referred-By header in the INVITE message.

• The Refer Target receiving the INVITE, reports the Referred-By header to host in the Request for Service message.

Message Trace

Below is the API and SIP trace for the call flow above but the Refer target in the trace is an Eyebeam softphone not a CSP.

CSP1:

H->X

[00 83 00 2c 00 00 01 00 01 0d 03 00 64 1f 02 03 00 1e 00 0f 00 02 01 16 00 02 00 00 01 1a 00 03 00 00 00 03 00 33 00 5d 00 09 27 7e 00 03 08 00 00 29 19 00 06 32 32 32 32 32 00 29 1b 00 0c 31 30 2e 31 30 2e 31 2e 32 35 32 00 29 1c 00 04 00 00 13 c4 29 23 00 06 31 31 31 31 31 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 27 92 00 04 0a 0a 01 bf 27 93 00 04 00 00 10 7c]

X->H

[00 07 00 2c 00 00 01 00 10]

X->H

[00 20 00 43 00 09 01 00 01 0d 03 00 64 1f 00 a7 00 24 01 03 00 33 00 0a 00 01 29 4a 00 04 00 00 00 00]

H->X

[00 05 00 43 00 09 01]

H->X

[00 05 00 43 00 09 01]

X->H

[00 58 00 43 00 0a 01 00 01 0d 03 00 64 1f 00 a7 00 20 01 03 00 33 00 42 00 03 29 2b 00 06 32 32 32 32 32 00 29 2d 00 06 32 32 32 32 32 00 29 ff 00 28 2a 0e 00 04 0a 0a 01 ab 2a 01 00 1c 2a 03 00 01 00 2a 07 00 04 00 00 3d 7c 2a 13 00 01 00 2a 02 00 06 2a 08 00 02 00 02]

H->X

[00 05 00 43 00 0a 01]

H->X

[00 05 00 43 00 0a 01]

H->X

[00 48 00 44 00 00 01 00 01 0d 03 00 64 1f 00 a7 00 27 01 03 00 33 00 32 00 05 29 1e 00 06 32 32 32 32 32 00 29 20 00 0c 31 30 2e 31 30 2e 31 2e 32 35 32 00 29 21 00 04 00 00 13 c4 29 29 00 00 29 2a 00 06 70 61 72 61 6d 00]

X->H

[00 07 00 44 00 00 01 00 10]

X->H

[00 1e 00 43 00 0b 01 00 01 0d 03 00 64 1f 00 a7 00 27 01 03 00 33 00 08 00 01 29 15 00 02 00 ca]

H->X

[00 05 00 43 00 0b 01]

H->X

[00 05 00 43 00 0b 01]

X->H

[00 25 00 43 00 0c 01 00 01 0d 03 00 64 1f 00 a7 00 28 01 03 00 33 00 0f 00 02 29 15 00 02 00 64 29 48 00 03 02 00 00]

H->X

[00 05 00 43 00 0c 01]

H->X

[00 05 00 43 00 0c 01]

X->H

[00 30 00 43 00 0d 01 00 01 0d 03 00 64 1f 00 a7 00 28 01 03 00 33 00 1a 00 02 29 15 00 02 00 c8 29 48 00 0e 00 00 00 6e 6f 72 65 73 6f 75 72 63 65 00]

H->X

[00 05 00 43 00 0d 01]

H->X

[00 05 00 43 00 0d 01]

H->X

[00 11 00 08 00 00 01 00 02 0d 03 00 64 1f 0d 03 00 64

1f]

X->H

[00 07 00 08 00 00 01 00 10]

X->H

[00 57 00 69 00 02 01 00 01 0d 03 00 64 1f 02 02 1e 2a 00 05 01 04 00 04 00 00 00 00 01 05 00 04 00 00 01 14 01 11 00 04 00 00 01 15 01 10 00 04 00 00 ac 80 01 12 00 04 00 00 ad 20 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 10 7c]

H->X

[00 05 00 69 00 02 01]

H->X

[00 05 00 69 00 02 01]

2

Printing all SIP messages

1 -RECEIVED From 10.10.1.2:5060 at 490

2 -SENT To 10.10.1.252:5060 at 494

INVITE sip:22222@10.10.1.252:5060 SIP/2.0

Via: SIP/2.0/UDP 10.10.1.250

To: 22222<sip:22222@10.10.1.252:5060>

From: 11111<sip:11111@10.10.1.250:5060>;tag=412726821ee

Call-ID: EXCEL-CSP1.101f.494.180@10.10.1.250

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

User-Agent: Excel_CSP/83.10.15

Supported: timer

Session-Expires: 1800

Min-SE: 300

CSeq: 1 INVITE

Content-Type: application/sdp

Content-Length: 100

v=0

o=sip 0 0 IN IP4 10.10.1.250

s=SIP_Call

c=IN IP4 10.10.1.191

t=0 0

m=audio 4220 RTP/AVP 0

3 -RECEIVED From 10.10.1.252:5060 at 494

SIP/2.0 100 Trying

To: 22222<sip:22222@10.10.1.252:5060>;tag=26821eb

From: 11111<sip:11111@10.10.1.250:5060>;tag=412726821ee

Call-ID: EXCEL-CSP1.101f.494.180@10.10.1.250

CSeq: 1 INVITE

Contact: 22222<sip:22222@10.10.1.252:5060>

Via: SIP/2.0/UDP 10.10.1.250

User-Agent: Excel_CSP/83.10.15

Content-Length: 0

4 -RECEIVED From 10.10.1.252:5060 at 494

SIP/2.0 180 Ringing

To: 22222<sip:22222@10.10.1.252:5060>;tag=26821eb

From: 11111<sip:11111@10.10.1.250:5060>;tag=412726821ee

Call-ID: EXCEL-CSP1.101f.494.180@10.10.1.250

CSeq: 1 INVITE

Contact: 22222<sip:22222@10.10.1.252:5060>

Via: SIP/2.0/UDP 10.10.1.250

User-Agent: Excel_CSP/83.10.15

Content-Length: 0

5 -RECEIVED From 10.10.1.252:5060 at 495

SIP/2.0 200 OK

To: 22222<sip:22222@10.10.1.252:5060>;tag=26821eb

From: 11111<sip:11111@10.10.1.250:5060>;tag=412726821ee

Call-ID: EXCEL-CSP1.101f.494.180@10.10.1.250

CSeq: 1 INVITE

Contact: 22222<sip:22222@10.10.1.252:5060>

Require: timer

Supported: timer

Session-Expires: 1800; refresher=uas

Via: SIP/2.0/UDP 10.10.1.250

User-Agent: Excel_CSP/83.10.15

Content-Type: application/sdp

Content-Length: 131

v=0

o=sip 1152893505 1152893505 IN IP4 10.10.1.252

s=SIP_Call

c=IN IP4 10.10.1.171

t=0 0

m=audio 15740 RTP/AVP 0

a=sendrecv

6 -SENT To 10.10.1.252:5060 at 495

ACK sip:22222@10.10.1.252:5060 SIP/2.0

Via: SIP/2.0/UDP 10.10.1.250

To: 22222<sip:22222@10.10.1.252:5060>;tag=26821eb

From: 11111<sip:11111@10.10.1.250:5060>;tag=412726821ee

Call-ID: EXCEL-CSP1.101f.494.180@10.10.1.250

CSeq: 1 ACK

Content-Length: 0

7 -SENT To 10.10.1.252:5060 at 497

REFER sip:22222@10.10.1.252:5060 SIP/2.0

Via: SIP/2.0/UDP 10.10.1.250

From: 11111<sip:11111@10.10.1.250:5060>;tag=412726821ee

To: 22222<sip:22222@10.10.1.252:5060>;tag=26821eb

Call-ID: EXCEL-CSP1.101f.494.180@10.10.1.250

CSeq: 2 REFER

Max-Forwards: 70

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

Refer-To: <sip:22222@10.10.1.252:5060>

Referred-By: <sip:11111@10.10.1.250:5060>;param

User-Agent: Excel_CSP/83.10.15

Content-Length: 0

8 -RECEIVED From 10.10.1.252:5060 at 497

SIP/2.0 202 Accepted

To: 22222<sip:22222@10.10.1.252:5060>;tag=26821eb

From: 11111<sip:11111@10.10.1.250:5060>;tag=412726821ee

Call-ID: EXCEL-CSP1.101f.494.180@10.10.1.250

CSeq: 2 REFER

Contact: 22222<sip:22222@10.10.1.252:5060>

Via: SIP/2.0/UDP 10.10.1.250

User-Agent: Excel_CSP/83.10.15

Content-Length: 0

9 -RECEIVED From 10.10.1.252:5060 at 497

NOTIFY sip:11111@10.10.1.250:5060 SIP/2.0

Via: SIP/2.0/UDP 10.10.1.252

To: 11111<sip:11111@10.10.1.250:5060>;tag=412726821ee

From: 22222<sip:22222@10.10.1.252:5060>;tag=26821eb

Call-ID: EXCEL-CSP1.101f.494.180@10.10.1.250

CSeq: 3 NOTIFY

Event: refer

Contact: 22222<sip:22222@10.10.1.252:5060>

Subscription-State: active

Content-Type: message/sipfrag;version=2.0

Content-Length: 20

SIP/2.0 100 Trying

10-SENT To 10.10.1.252:5060 at 497

SIP/2.0 200 OK

To: 11111<sip:11111@10.10.1.250:5060>;tag=412726821ee

From: 22222<sip:22222@10.10.1.252:5060>;tag=26821eb

Call-ID: EXCEL-CSP1.101f.494.180@10.10.1.250

CSeq: 3 NOTIFY

Via: SIP/2.0/UDP 10.10.1.252

User-Agent: Excel_CSP/83.10.15

Content-Length: 0

11-RECEIVED From 10.10.1.2:5060 at 499

12-RECEIVED From 10.10.1.252:5060 at 500

NOTIFY sip:11111@10.10.1.250:5060 SIP/2.0

Via: SIP/2.0/UDP 10.10.1.252

To: 11111<sip:11111@10.10.1.250:5060>;tag=412726821ee

From: 22222<sip:22222@10.10.1.252:5060>;tag=26821eb

Call-ID: EXCEL-CSP1.101f.494.180@10.10.1.250

CSeq: 4 NOTIFY

Event: refer

Contact: 22222<sip:22222@10.10.1.252:5060>

Subscription-State: terminated;reason=noresource

Content-Type: message/sipfrag;version=2.0

Content-Length: 16

SIP/2.0 200 OK

13-SENT To 10.10.1.252:5060 at 500

SIP/2.0 200 OK

To: 11111<sip:11111@10.10.1.250:5060>;tag=412726821ee

From: 22222<sip:22222@10.10.1.252:5060>;tag=26821eb

Call-ID: EXCEL-CSP1.101f.494.180@10.10.1.250

CSeq: 4 NOTIFY

Via: SIP/2.0/UDP 10.10.1.252

User-Agent: Excel_CSP/83.10.15

Content-Length: 0

14-SENT To 10.10.1.252:5060 at 500

BYE sip:22222@10.10.1.252:5060 SIP/2.0

Via: SIP/2.0/UDP 10.10.1.250

To: 22222<sip:22222@10.10.1.252:5060>;tag=26821eb

From: 11111<sip:11111@10.10.1.250:5060>;tag=412726821ee

Call-ID: EXCEL-CSP1.101f.494.180@10.10.1.250

CSeq: 3 BYE

User-Agent: Excel_CSP/83.10.15

Content-Length: 0

15-RECEIVED From 10.10.1.252:5060 at 500

SIP/2.0 200 OK

To: 22222<sip:22222@10.10.1.252:5060>;tag=26821eb

From: 11111<sip:11111@10.10.1.250:5060>;tag=412726821ee

Call-ID: EXCEL-CSP1.101f.494.180@10.10.1.250

CSeq: 3 BYE

Via: SIP/2.0/UDP 10.10.1.250

User-Agent: Excel_CSP/83.10.15

Content-Length: 0

CSP2:

X->H

[01 6e 00 2d 00 02 02 00 01 0d 03 00 c8 02 00 33 01 03 00 33 01 5a 00 1a 27 4e 00 02 00 05 27 7e 00 03 08 00 00 29 19 00 06 32 32 32 32 32 00 29 1b 00 0c 31 30 2e 31 30 2e 31 2e 32 35 32 00 29 1c 00 04 00 00 13 c4 29 23 00 06 31 31 31 31 31 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 06 31 31 31 31 31 00 29 2d 00 06 31 31 31 31 31 00 29 2f 00 0c 31 30 2e 31 30 2e 31 2e 32 35 30 00 29 30 00 04 00 00 13 c4 29 33 00 01 01 27 18 00 08 02 00 00 00 05 11 11 10 27 17 00 06 02 00 05 22 22 20 29 16 00 01 01 29 54 00 06 32 32 32 32 32 00 29 55 00 0c 31 30 2e 31 30 2e 31 2e 32 35 32 00 29 56 00 04 00 00 13 c4 29 50 00 24 45 58 43 45 4c 2d 43 53 50 31 2e 31 30 31 66 2e 34 39 34 2e 31 38 30 40 31 30 2e 31 30 2e 31 2e 32 35 30 00 29 51 00 0c 34 31 32 37 32 36 38 32 31 65 65 00 29 52 00 08 32 36 38 32 31 65 62 00 2a 0e 00 04 0a 0a 01 bf 29 9a 00 1a 29 9b 00 02 00 22 29 9c 00 10 29 5e 00 0c 31 30 2e 31 30 2e 31 2e 32 35 30 00 29 4a 00 04 00 00 00 01 29 ff 00 23 2a 0e 00 04 0a 0a 01 bf 2a 01 00 17 2a 03 00 01 00 2a 07 00 04 00 00 10 7c 2a 02 00 06 2a 08 00 02 00 02]

H->X

[00 0c 00 2d 00 02 02 00 01 0d 03 00 c8 02]

H->X

[00 0c 00 2d 00 02 02 00 01 0d 03 00 c8 02]

H->X

[00 11 00 bf 00 00 02 00 02 0d 03 00 c8 02 0d 03 00 c8

02]

X->H

[00 07 00 bf 00 00 02 00 10]

H->X

[00 0d 00 ba 00 00 02 00 01 0d 03 00 c8 02 01]

X->H

[00 07 00 ba 00 00 02 00 10]

X->H

[00 77 00 43 00 04 02 00 01 0d 03 00 c8 02 00 a7 00 21 01 03 00 33 00 61 00 07 29 2b 00 06 31 31 31 31 31 00 29 2d 00 06 31 31 31 31 31 00 29 19 00 06 32 32 32 32 32 00 29 1b 00 0c 31 30 2e 31 30 2e 31 2e 32 35 32 00 29 1c 00 04 00 00 13 c4 29 29 00 1b 73 69 70 3a 31 31 31 31 31 40 31 30 2e 31 30 2e 31 2e 32 35 30 3a 35 30 36 30 00 29 2a 00 06 70 61 72 61 6d 00]

H->X

[00 05 00 43 00 04 02]

H->X

[00 05 00 43 00 04 02]

H->X

[00 1e 00 44 00 00 02 00 01 0d 03 00 c8 02 00 a7 00 20 01 03 00 33 00 08 00 01 29 4b 00 02 00 64]

X->H

[00 07 00 44 00 00 02 00 10]

H->X

[00 a6 00 2c 00 01 02 00 01 0d 03 00 c8 1f 02 03 00 1e 00 0f 00 02 01 16 00 02 00 00 01 1a 00 03 00 0d 00 03 00 33 00 80 00 0b 27 7e 00 03 08 00 00 29 19 00 06 32 30 35 39 37 00 29 1b 00 0a 31 30 2e 31 30 2e 31 2e 32 00 29 1c 00 04 00 00 13 c4 29 23 00 06 32 32 32 32 32 00 29 25 00 0c 31 30 2e 31 30 2e 31 2e 32 35 32 00 29 26 00 04 00 00 13 c4 27 92 00 04 0a 0a 01 ac 27 93 00 04 00 00 20 8c 29 29 00 17 31 31 31 31 31 40 31 30 2e 31 30 2e 31 2e 32 35 30 3a 35 30 36 30 00 29 2a 00 06 70 61 72 61 6d 00]

X->H

[00 07 00 2c 00 01 02 00 10]

X->H

[00 20 00 43 00 05 02 00 01 0d 03 00 c8 1f 00 a7 00 24 01 03 00 33 00 0a 00 01 29 4a 00 04 00 00 00 00]

H->X

[00 05 00 43 00 05 02]

H->X

[00 05 00 43 00 05 02]

X->H

[00 5b 00 43 00 06 02 00 01 0d 03 00 c8 1f 00 a7 00 20 01 03 00 33 00 45 00 02 29 2d 00 06 32 30 35 39 37 00 29 ff 00 35 2a 0e 00 04 0a 0a 01 02 2a 01 00 29 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]

H->X

[00 05 00 43 00 06 02]

H->X

[00 05 00 43 00 06 02]

H->X

[00 1e 00 44 00 00 02 00 01 0d 03 00 c8 02 00 a7 00 20 01 03 00 33 00 08 00 01 29 4b 00 02 00 c8]

X->H

[00 07 00 44 00 00 02 00 10]

X->H

[00 57 00 69 00 02 02 00 01 0d 03 00 c8 02 02 02 1e 2a 00 05 01 04 00 04 00 00 00 00 01 05 00 04 00 00 01 13 01 11 00 04 00 00 01 20 01 10 00 04 00 00 ab e0 01 12 00 04 00 00 b4 00 03 00 33 00 18 00 03 27 4e 00 02 00 10 27 92 00 04 0a 0a 01 ab 27 93 00 04 00 00 3d 7c]

H->X

[00 05 00 69 00 02 02]

H->X

[00 05 00 69 00 02 02]

H->X

[00 11 00 08 00 00 02 00 02 0d 03 00 c8 1f 0d 03 00 c8

1f]

X->H

[00 07 00 08 00 00 02 00 10]

X->H

[00 57 00 69 00 03 02 00 01 0d 03 00 c8 1f 02 02 1e 2a 00 05 01 04 00 04 00 00 00 00 01 05 00 04 00 00 00 6c 01 11 00 04 00 00 00 7f 01 10 00 04 00 00 43 80 01 12 00 04 00 00 4f 60 03 00 33 00 18 00 03 27 4e 00 02 00 10 27 92 00 04 0a 0a 01 ac 27 93 00 04 00 00 20 8c]

H->X

[00 05 00 69 00 03 02]

2

Printing all SIP messages

1 -RECEIVED From 10.10.1.250:5060 at 491

INVITE sip:22222@10.10.1.252:5060 SIP/2.0

Via: SIP/2.0/UDP 10.10.1.250

To: 22222<sip:22222@10.10.1.252:5060>

From: 11111<sip:11111@10.10.1.250:5060>;tag=412726821ee

Call-ID: EXCEL-CSP1.101f.494.180@10.10.1.250

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

User-Agent: Excel_CSP/83.10.15

Supported: timer

Session-Expires: 1800

Min-SE: 300

CSeq: 1 INVITE

Content-Type: application/sdp

Content-Length: 100

v=0

o=sip 0 0 IN IP4 10.10.1.250

s=SIP_Call

c=IN IP4 10.10.1.191

t=0 0

m=audio 4220 RTP/AVP 0

2 -SENT To 10.10.1.250:5060 at 491

SIP/2.0 100 Trying

To: 22222<sip:22222@10.10.1.252:5060>;tag=26821eb

From: 11111<sip:11111@10.10.1.250:5060>;tag=412726821ee

Call-ID: EXCEL-CSP1.101f.494.180@10.10.1.250

CSeq: 1 INVITE

Contact: 22222<sip:22222@10.10.1.252:5060>

Via: SIP/2.0/UDP 10.10.1.250

User-Agent: Excel_CSP/83.10.15

Content-Length: 0

3 -SENT To 10.10.1.250:5060 at 492

SIP/2.0 180 Ringing

To: 22222<sip:22222@10.10.1.252:5060>;tag=26821eb

From: 11111<sip:11111@10.10.1.250:5060>;tag=412726821ee

Call-ID: EXCEL-CSP1.101f.494.180@10.10.1.250

CSeq: 1 INVITE

Contact: 22222<sip:22222@10.10.1.252:5060>

Via: SIP/2.0/UDP 10.10.1.250

User-Agent: Excel_CSP/83.10.15

Content-Length: 0

4 -SENT To 10.10.1.250:5060 at 492

SIP/2.0 200 OK

To: 22222<sip:22222@10.10.1.252:5060>;tag=26821eb

From: 11111<sip:11111@10.10.1.250:5060>;tag=412726821ee

Call-ID: EXCEL-CSP1.101f.494.180@10.10.1.250

CSeq: 1 INVITE

Contact: 22222<sip:22222@10.10.1.252:5060>

Require: timer

Supported: timer

Session-Expires: 1800; refresher=uas

Via: SIP/2.0/UDP 10.10.1.250

User-Agent: Excel_CSP/83.10.15

Content-Type: application/sdp

Content-Length: 131

v=0

o=sip 1152893505 1152893505 IN IP4 10.10.1.252

s=SIP_Call

c=IN IP4 10.10.1.171

t=0 0

m=audio 15740 RTP/AVP 0

a=sendrecv

5 -RECEIVED From 10.10.1.250:5060 at 493

ACK sip:22222@10.10.1.252:5060 SIP/2.0

Via: SIP/2.0/UDP 10.10.1.250

To: 22222<sip:22222@10.10.1.252:5060>;tag=26821eb

From: 11111<sip:11111@10.10.1.250:5060>;tag=412726821ee

Call-ID: EXCEL-CSP1.101f.494.180@10.10.1.250

CSeq: 1 ACK

Content-Length: 0

6 -RECEIVED From 10.10.1.250:5060 at 495

REFER sip:22222@10.10.1.252:5060 SIP/2.0

Via: SIP/2.0/UDP 10.10.1.250

From: 11111<sip:11111@10.10.1.250:5060>;tag=412726821ee

To: 22222<sip:22222@10.10.1.252:5060>;tag=26821eb

Call-ID: EXCEL-CSP1.101f.494.180@10.10.1.250

CSeq: 2 REFER

Max-Forwards: 70

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

Refer-To: <sip:22222@10.10.1.252:5060>

Referred-By: <sip:11111@10.10.1.250:5060>;param

User-Agent: Excel_CSP/83.10.15

Content-Length: 0

7 -SENT To 10.10.1.250:5060 at 495

SIP/2.0 202 Accepted

To: 22222<sip:22222@10.10.1.252:5060>;tag=26821eb

From: 11111<sip:11111@10.10.1.250:5060>;tag=412726821ee

Call-ID: EXCEL-CSP1.101f.494.180@10.10.1.250

CSeq: 2 REFER

Contact: 22222<sip:22222@10.10.1.252:5060>

Via: SIP/2.0/UDP 10.10.1.250

User-Agent: Excel_CSP/83.10.15

Content-Length: 0

8 -SENT To 10.10.1.250:5060 at 495

NOTIFY sip:11111@10.10.1.250:5060 SIP/2.0

Via: SIP/2.0/UDP 10.10.1.252

To: 11111<sip:11111@10.10.1.250:5060>;tag=412726821ee

From: 22222<sip:22222@10.10.1.252:5060>;tag=26821eb

Call-ID: EXCEL-CSP1.101f.494.180@10.10.1.250

CSeq: 3 NOTIFY

Event: refer

Contact: 22222<sip:22222@10.10.1.252:5060>

Subscription-State: active

Content-Type: message/sipfrag;version=2.0

Content-Length: 20

SIP/2.0 100 Trying

9 -RECEIVED From 10.10.1.250:5060 at 495

SIP/2.0 200 OK

To: 11111<sip:11111@10.10.1.250:5060>;tag=412726821ee

From: 22222<sip:22222@10.10.1.252:5060>;tag=26821eb

Call-ID: EXCEL-CSP1.101f.494.180@10.10.1.250

CSeq: 3 NOTIFY

Via: SIP/2.0/UDP 10.10.1.252

User-Agent: Excel_CSP/83.10.15

Content-Length: 0

10-SENT To 10.10.1.2:5060 at 495

INVITE sip:20597@10.10.1.2:5060 SIP/2.0

Via: SIP/2.0/UDP 10.10.1.252

To: 20597<sip:20597@10.10.1.2:5060>

From: 22222<sip:22222@10.10.1.252:5060>;tag=412786241ef

Call-ID: EXCEL-CSP2.101f.495.990@10.10.1.252

Contact: 22222<sip:22222@10.10.1.252:5060>

User-Agent: Excel_CSP/83.10.15

Supported: timer

Session-Expires: 1800

Min-SE: 300

CSeq: 1 INVITE

Referred-By: <11111@10.10.1.250:5060>;param

Content-Type: application/sdp

Content-Length: 100

v=0

o=sip 0 0 IN IP4 10.10.1.252

s=SIP_Call

c=IN IP4 10.10.1.172

t=0 0

m=audio 8332 RTP/AVP 0

11-RECEIVED From 10.10.1.2:5060 at 496

SIP/2.0 180 Ringing

Via: SIP/2.0/UDP 10.10.1.252

Contact: <sip:20597@10.10.1.2:5060>

To: "20597"<sip:20597@10.10.1.2:5060>;tag=7204a018

From: "22222"<sip:22222@10.10.1.252:5060>;tag=412786241ef

Call-ID: EXCEL-CSP2.101f.495.990@10.10.1.252

CSeq: 1 INVITE

User-Agent: eyeBeam release 3010n stamp 19039

Content-Length: 0

12-RECEIVED From 10.10.1.2:5060 at 498

SIP/2.0 200 OK

Via: SIP/2.0/UDP 10.10.1.252

Contact: <sip:20597@10.10.1.2:5060>

To: "20597"<sip:20597@10.10.1.2:5060>;tag=7204a018

From: "22222"<sip:22222@10.10.1.252:5060>;tag=412786241ef

Call-ID: EXCEL-CSP2.101f.495.990@10.10.1.252

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: 187

v=0

o=- 87437649 87437674 IN IP4 10.10.1.2

s=eyeBeam

c=IN IP4 10.10.1.2

t=0 0

m=audio 8306 RTP/AVP 0

a=alt:1 1 : 1DE6CC47 0000007B 10.10.1.2 8306

a=rtpmap:0 pcmu/8000

a=sendrecv

13-SENT To 10.10.1.2:5060 at 498

ACK sip:20597@10.10.1.2:5060 SIP/2.0

Via: SIP/2.0/UDP 10.10.1.252

To: 20597<sip:20597@10.10.1.2:5060>;tag=7204a018

From: 22222<sip:22222@10.10.1.252:5060>;tag=412786241ef

Call-ID: EXCEL-CSP2.101f.495.990@10.10.1.252

CSeq: 1 ACK

Content-Length: 0

14-SENT To 10.10.1.250:5060 at 498

NOTIFY sip:11111@10.10.1.250:5060 SIP/2.0

Via: SIP/2.0/UDP 10.10.1.252

To: 11111<sip:11111@10.10.1.250:5060>;tag=412726821ee

From: 22222<sip:22222@10.10.1.252:5060>;tag=26821eb

Call-ID: EXCEL-CSP1.101f.494.180@10.10.1.250

CSeq: 4 NOTIFY

Event: refer

Contact: 22222<sip:22222@10.10.1.252:5060>

Subscription-State: terminated;reason=noresource

Content-Type: message/sipfrag;version=2.0

Content-Length: 16

SIP/2.0 200 OK

15-RECEIVED From 10.10.1.250:5060 at 498

SIP/2.0 200 OK

To: 11111<sip:11111@10.10.1.250:5060>;tag=412726821ee

From: 22222<sip:22222@10.10.1.252:5060>;tag=26821eb

Call-ID: EXCEL-CSP1.101f.494.180@10.10.1.250

CSeq: 4 NOTIFY

Via: SIP/2.0/UDP 10.10.1.252

User-Agent: Excel_CSP/83.10.15

Content-Length: 0

16-RECEIVED From 10.10.1.250:5060 at 498

BYE sip:22222@10.10.1.252:5060 SIP/2.0

Via: SIP/2.0/UDP 10.10.1.250

To: 22222<sip:22222@10.10.1.252:5060>;tag=26821eb

From: 11111<sip:11111@10.10.1.250:5060>;tag=412726821ee

Call-ID: EXCEL-CSP1.101f.494.180@10.10.1.250

CSeq: 3 BYE

User-Agent: Excel_CSP/83.10.15

Content-Length: 0

17-SENT To 10.10.1.250:5060 at 498

SIP/2.0 200 OK

To: 22222<sip:22222@10.10.1.252:5060>;tag=26821eb

From: 11111<sip:11111@10.10.1.250:5060>;tag=412726821ee

Call-ID: EXCEL-CSP1.101f.494.180@10.10.1.250

CSeq: 3 BYE

Via: SIP/2.0/UDP 10.10.1.250

User-Agent: Excel_CSP/83.10.15

Content-Length: 0

18-SENT To 10.10.1.2:5060 at 500

BYE sip:20597@10.10.1.2:5060 SIP/2.0

Via: SIP/2.0/UDP 10.10.1.252

To: "20597"<sip:20597@10.10.1.2:5060>;tag=7204a018

From: "22222"<sip:22222@10.10.1.252:5060>;tag=412786241ef

Call-ID: EXCEL-CSP2.101f.495.990@10.10.1.252

CSeq: 2 BYE

User-Agent: Excel_CSP/83.10.15

Content-Length: 0

19-RECEIVED From 10.10.1.2:5060 at 500

SIP/2.0 200 OK

Via: SIP/2.0/UDP 10.10.1.252

Contact: <sip:20597@10.10.1.2:5060>

To: "20597"<sip:20597@10.10.1.2:5060>;tag=7204a018

From: "22222"<sip:22222@10.10.1.252:5060>;tag=412786241ef

Call-ID: EXCEL-CSP2.101f.495.990@10.10.1.252

CSeq: 2 BYE

User-Agent: eyeBeam release 3010n stamp 19039

Content-Length: 0

Call Flow - How to handle REFER with cid token (Secure REFER)

The call flow below provides an example how to inform the Referrer that the Referee does not support secure REFER. The Referred-By header in REFER request with "cid" token shall be reported to the host. The host is expected to parse and find out if this a secure ("cid" token present) or insecure REFER request. In case of secure REFER, the host can use PPL ER to generate NOTIFY with a message/sipfrag body indicating a final response of 501 "Not Implemented" to the Referrer. The host decides the final response to be used in the NOTIFY message body. Response 501 is an example:

Call Flow - How to handle 429 response for INVITE w/ Referred-By header

The call flow below shows an example of how to handle a 429 response for a INVITE w/ Referred-By header. If the INVITE message receives a 3xx-6xx response, the call is dropped and the channel is released. The channel-released API contains the response received for INVITE within the NPDI SIP Response Code TLV (0x2915). If the response is 429 "Provide Referrer Identity", then the refer target requires a valid Referred-By token to accept the INVITE request (Secure REFER). This is informed to the Referrer using NOTIFY with a message/sipfrag body indicating a final response of 429.

New TLVs

0x027F - SIP Message Information Mask TLV

Used in:
VoIP Protocol Configure message
VoIP Protocol Query message

Byte | Description
0, 1 | Tag 0x027F
2, 3 | Length 0x0004
4-n | Value[0-3] This field is a 32-bit mask. Each bit selects specific SIP message fields and is listed from LSB to MSB. Bit 18 - Selects reporting of Referred-By header in REFER and INVITE request

0x2929 - SIP Referred By Header URI TLV

This TLV does the following:

• Instructs the CSP SIP stack to insert Referred-By header in the outbound REFER. In case no data is provided CSP SIP stack fills in the contact URI.

• Reports the URI in the Referred-By header, if present, in the received REFER or INVITE request.

• Writes the URI of the Referred-By header in the outbound INVITE request.

Used in:

Route Control
Outseize Control
Request For Service with Data
PPL Event Request
PPL Event Indication

Byte | Description
0, 1 | Tag 0x2929
2, 3 | Length Variable (Maximum is 100)
4-n | Value[0-3] Null Terminated ASCII string

0x292A - SIP Referred By Header Parameters TLV

This TLV does the following:

• Reports the Referred-By header parameters, if present, in the received REFER or INVITE request.

• Writes the parameters of the Referred-By header in the outbound REFER or INVITE request.

Used in:

Route Control
Outseize Control
Request For Service with Data
PPL Event Request
PPL Event Indication

Byte | Description
0, 1 | Tag 0x292A
2, 3 | Length Variable (Maximum is 100)
4-n | Value Null Terminated ASCII string

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 Programmable Protocol Language.
Outgoing call setup during real-time call processing on a specific channel.
See Request For Service.
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.
RFS. A Status Message indicating that some entity is requesting service from the Excel platform.
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).
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.
Real-Time Transport Protocol. Supports transport of real-time data like interactive voice and video over packet-switched networks.
Positive acknowledgment to a message
The condition of a component at a given instant. The current "context" of a PPL object, such as Idle, Seizing, Answered. In PPL files, a State is represented by a circle.
Network Protocol Data Intelligence. Also called “Interworking,” it is a software product that operates within Excel’s Call Control (Layer 4) and Services (Layer 5) call processing layers. NPDI is meant to enhance Excel’s call processing product offering by allowing call processing layers (specifically Layers 4 and 5) to perform advanced analysis, generation, and conversion of Network Signaling (NS) Layer 3 information.
Tag-Length-Value block. A standardized block that allows data to inserted in a standard way into API messages.
Least Significant Bit
Most Significant Bit
American Standard Code for Information Interchange