Trunk Parameters

Cloud Voice can export your SIP (Session Initiation Protocol) trunks to a CSV (comma-separated values) file and create trunks in bulk by importing that same format. This page describes every column in the file so you can build a valid import or make sense of an export.

Note

Only SIP peer trunks and register trunks can be exported and imported. Account trunks are not supported.

Blank fields on import

When you import a trunk and leave a field empty, Cloud Voice applies the value shown in the Default column, wherever one is listed. Fields whose default is N/A stay empty.

Parameters

Acronyms used in this table

• DID / DDI (Direct Inward Dialing / Direct Dialing In): an external number that routes an incoming call to your phone system.
• DOD (Direct Outward Dialing): the outbound caller ID a user picks for a specific call.
• DTMF (Dual-Tone Multi-Frequency): the tones a phone keypad sends, used for menus and codes.
• SDP (Session Description Protocol): the media details (codecs, ports) carried inside a SIP message.
• SRTP (Secure Real-time Transport Protocol): encrypted call media, the secured form of RTP (Real-time Transport Protocol).
• SIP URI: a SIP address written as sip:user@domain.

Parameter	Description	Requirement	Values and rules	Default
Name	Identifies the trunk.	Required	Up to 63 characters. Spaces and special characters are not allowed, and the name must be unique.	N/A
Trunk Status	Turns the trunk on or off.	Required	0 (disabled) or 1 (enabled).	1
Trunk Type	The kind of trunk.	Required	register, did_based, port_based, or private_network. Account trunks cannot be imported.	register
Transport	Signaling transport agreed with the provider.	Required	Depends on Trunk Type: port_based allows udp; did_based allows udp or tcp; private_network allows udp, tcp, or tls; register allows udp, tcp, tls, or dnsnaptr.	udp
Hostname/IP	The provider’s IP address or domain.	Required	Up to 255 characters.	N/A
Port	The signaling port for the trunk.	Required	A number from 0 to 65535.	N/A
Domain	The domain used in the SIP URI of headers such as From and To. If the provider does not supply one, reuse the Hostname/IP value.	Required	Up to 255 characters.	N/A
Username	The account name used to register with the provider.	Required when Trunk Type is register.	Up to 255 characters.	N/A
Password	The password paired with the username.	Required when Trunk Type is register.	Up to 255 characters.	N/A
Authentication Name	The authentication identity used to register with the provider.	Optional	Up to 255 characters.	N/A
Enable Outbound Proxy	Whether calls are routed through an outbound proxy.	Required when Trunk Type is register.	0 (disabled) or 1 (enabled).	0
Outbound Proxy Server	Address of the outbound proxy.	Required when Enable Outbound Proxy is 1.	Up to 255 characters.	N/A
Port of Outbound Proxy Server	Port of the outbound proxy.	Required when Enable Outbound Proxy is 1.	A number from 1 to 65535.	N/A
Codec Setting	Audio and video codecs offered on the trunk.	Required	One or more of ulaw, alaw, g729, gsm, h264, h263, h263p, ilbc, g722, g726, speex, adpcm, vp8, mpeg4, opus. List them in preference order joined by & (for example, ulaw&alaw). Any unsupported entry is ignored.	ulaw&alaw&gsm&h264&ilbc&g722&g726&g729
DTMF Mode	How DTMF tones are sent.	Required	rfc4733, info, inband, or auto.	rfc4733
DTMF FMTP	The fmtp value used when DTMF Mode is rfc4733.	Optional	0-16 or 0-15.	0-16
Qualify	Whether to send SIP OPTIONS packets to check that the peer is reachable.	Required	0 (disabled) or 1 (enabled).	1
Enable SRTP	Whether to encrypt media (RTP) on the trunk.	Required	0 (disabled) or 1 (enabled).	0
T.38 Support	Whether T.38 fax is allowed.	Required	0 (disabled) or 1 (enabled).	0
Inband Progress	Whether inband progress is used.	Required	0 (disabled) or 1 (enabled).	0
Ignore 183 Message without SDP	Whether to drop 183 responses that carry no SDP.	Required	0 (disabled) or 1 (enabled).	0
Forward the 180 (SDP) Message Following the Peer’s Format	Whether Cloud Voice mirrors the far end, sending a 180 with SDP only when the 180 it received contained SDP.	Required	0 (disabled) or 1 (enabled).	0
Dedicated Trunk	Whether the trunk needs a dedicated internal IP address to connect.	Optional	0 (disabled) or 1 (enabled).	0
Enable SIP Authentication Cache	Whether Cloud Voice caches a successful SIP authentication and reuses it for later requests (such as INVITE and BYE) within the same session or registration cycle.	Optional	0 (disabled) or 1 (enabled).	0
Force SIP URI Scheme	Whether to force the sip: scheme instead of sips: in registration requests, downgrading signaling from encrypted to unencrypted. Available only when Trunk Type is register and Transport is tls or dnsnaptr.	Optional	0 (disabled) or 1 (enabled).	0
Ignore 100 Trying Response	Whether to ignore the 100 Trying response. Available only when Trunk Type is register.	Optional	0 (disabled) or 1 (enabled).	0
Support SIP REFER	Whether the trunk accepts SIP REFER requests.	Optional	0 (disabled) or 1 (enabled).	0
Allow Transfer To	Destination types permitted for blind transfers driven by REFER. Available only when Support SIP REFER is 1.	Required when Support SIP REFER is 1.	external_number, internal_number, or external_number&internal_number.	N/A
Prefix	Prefix that Cloud Voice prepends to the REFER target number so a blind transfer matches an outbound route. Available only when Support SIP REFER is 1 and Allow Transfer To includes external numbers.	Optional	Digits and the characters * # ( ) . - +; up to 7 characters.	N/A
Maximum Concurrent Calls	Cap on simultaneous calls over the trunk.	Required	Digits only, up to 5 characters; 0 means unlimited.	0
Call Restriction Type	Which calls the concurrent-call cap applies to.	Required	outbound or all.	outbound
Outbound Failover SIP Code	Whether failover uses the built-in SIP codes or a custom list. When a matching code is returned, the call fails over to the next trunk on the outbound route and is retried.	Required	default (codes 408, 500, 502, 503, 513, 555, 580) or custom.	default
SIP Codes	The response codes that trigger failover when Outbound Failover SIP Code is custom.	Required when Outbound Failover SIP Code is custom.	Up to 127 characters, allowing as many as 32 codes separated by ;. Only codes in the 300-699 range take effect.	408;500;502;503;513;555;580
Default Outbound Caller ID	The caller ID shown on the callee’s device. It must be permitted by the provider.	Optional	Digits, letters, and the characters ( ) . - + * #; up to 31 characters.	N/A
Default Outbound Caller ID Name	The caller ID name shown on the callee’s device.	Optional	Up to 127 characters.	N/A
Get Caller ID From	Which SIP header the trunk reads the caller ID from on inbound calls.	Required	follow_system, from, contact, rpid, pai, or ppi.	follow_system
Get DID From	Which SIP header the trunk reads the DID from on inbound calls. Because providers place the DID in different headers, set this after inspecting the provider’s SIP packets; an incorrect header causes the call to fail.	Required	follow_system, to, invite, diversion, rpid, pai, ppi, or pcpid.	follow_system
From User Part	The caller ID placed in the user part of the From header.	Required	default, ext_cid, trunk_user (register trunks only), trunk_def_outbcid, ext_outbcid, outrounter_outbcid, originator_cid, or a custom value (digits, letters, and ( ) . - + * #; up to 31 characters).	default
From Display Name Part	The caller ID name placed in the display-name part of the From header.	Required	default, ext_cid_name, trunk_def_outbcid_name, ext_outbcid_name, originator_cid_name, or a custom value (up to 63 characters).	default
Diversion	The value carried in the Diversion header. Leave empty to omit the header.	Optional	default, ext_cid, trunk_user (register trunks only), trunk_def_outbcid, ext_outbcid, outrounter_outbcid, originator_cid, or a custom value (up to 31 characters, using digits, letters, and ( ) . - + * #).	N/A
Remote-Party-ID	The value carried in the Remote-Party-ID header. Leave empty to omit the header.	Optional	Same choices as Diversion.	N/A
P-Asserted-Identity	The value carried in the P-Asserted-Identity header. Leave empty to omit the header.	Optional	Same choices as Diversion.	N/A
P-Preferred-Identity	The value carried in the P-Preferred-Identity header. Leave empty to omit the header.	Optional	Same choices as Diversion.	N/A
From Host Part	The domain or IP placed in the From field of the SIP INVITE. Applies to peer trunks only.	Required	default or a custom value (up to 255 characters).	default
To Host Part	The domain or IP placed in the To field of the SIP INVITE. Applies to peer trunks only.	Required	default or a custom value (up to 255 characters).	default
User Agent	The User Agent string, when the provider requires it for authentication.	Optional	Up to 255 characters.	N/A
Realm	The realm string presented to users so they know which credentials to use.	Optional	Up to 255 characters.	N/A
Send Privacy ID	Whether to include the Privacy ID in the SIP header.	Required	0 (disabled) or 1 (enabled).	0
User Phone	Whether to append user=phone to the request line of the SIP INVITE.	Required	0 (disabled) or 1 (enabled).	0
Send X-OpenAPI-Call-ID	Whether to add an X-OpenAPI-Call-ID header to the SIP INVITE so the Call ID travels with inbound and outbound calls routed over the trunk.	Required	0 (disabled) or 1 (enabled).	0
100rel	How the trunk handles 100rel (reliable provisional responses).	Required	Required, Supported, or Disabled.	Disabled
Maxptime	The Maxptime advertised in outbound INVITEs.	Required	default (Cloud Voice sends a value matching the codec used for the call) or a custom value that is a multiple of 10 from 20 to 300.	default
Support P-Early-Media	Whether the INVITE includes the P-Early-Media header.	Required	0 (disabled) or 1 (enabled).	0
DID/DDI	A virtual number that identifies which path of the trunk is carrying the call.	Required when Trunk Type is register or did_based.	Up to 31 characters. For register or did_based: digits, letters, and ( ) . - + * #. For port_based or private_network: digits, letters, and [ ] * # ( ) . - + !.	N/A
DID/DDI Name	A label for the DID/DDI.	Optional	Up to 127 characters.	N/A
Force Selected DOD in From Header	Whether to ignore the trunk’s From User Part setting and force the extension’s chosen DOD number into the From header when a user selects a specific DOD for an outbound call.	Optional	0 (disabled) or 1 (enabled).	1
Return 302 on External Forward	Whether to return a 302 Moved Temporarily response when an inbound call is forwarded to an external number, letting the carrier redirect the call itself.	Optional	0 (disabled) or 1 (enabled).	0