The X-Msw-Companion-Device header is a custom SIP header used by Sentinel VoLTE when
a companion device may be used on a call.
The terminating MMTel-AS instance inserts this header in the initial INVITE if the served user’s
Metaswitch-TAS-Services transparent data indicates that they have a companion device.
If the subscriber has multiple companion devices, multiple header values will be inserted.
The header conveys this information to the terminating SCC-AS instance.
The T-ADS features in the SCC-AS will use this
information to decide whether the INVITE should be forked to the companion device.
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Header Format
The header name is X-Msw-Companion-Device, and its value is the companion device information provisioned for the subscriber.
The header is presented in the following format:
X-Msw-Companion-Device: <radioAccessType>[;<parameters>]<radioAccessType> is either CS, PS, or PS-CS,
where PS value indicates the subscriber has a companion device supporting packet-switched radio access types, e.g. LTE or WiFi.
CS value indicates the companion device supports 3G network.
The <parameters> are normal SIP name=value header parameters which can include common parameters and CS only parameters.
Common Parameters
| Parameter | Description | Example | Mandatory or Optional |
|---|---|---|---|
model |
quoted-string containing the companion model |
model="CompanionWatch" |
Optional |
impi |
quoted-string containing an IMPI (23.003 §13.3) |
Optional |
|
imsi |
quoted-string containing an IMSI (23.003 §2.2) |
imsi="234150999999999" |
Optional |
imei |
quoted-string containing an IMEI (23.003 §13.13) |
imei="sip:90420156-025763-0@ims.mnc015.mcc234.3gppnetwork.org" |
Optional |
CS Only Parameters
| Parameter | Description | Example | Mandatory or Optional |
|---|---|---|---|
msisdn |
quoted-string containing an MSISDN |
msisdn="1234567" |
Mandatory |
Example:
-
For PS companion device:
X-Msw-Companion-Device: PS;model="CompanionWatch" -
For CS companion device with optional parameters:
X-Msw-Companion-Device: CS;model="CompanionGlass";msisdn="1234567";imei="sip:90420156-025763-0@ims.mnc015.mcc234.3gppnetwork.org" -
For multiple devices:
X-Msw-Companion-Device: PS-CS;model="CompanionWatch";msisdn="1234567";imei="sip:90420156-025763-0@ims.mnc015.mcc234.3gppnetwork.org X-Msw-Companion-Device: CS;model="CompanionGlass";msisdn="1234568"
Header Usage
The header is set by Set Companion Device Headers feature.
The header is decoded by SCC Decode Companion Device Info feature.
