SIP connectivity reference#

Use this reference to look up the network, signaling, media, authentication, encryption, codec, DTMF, monitoring, and firewall specifications for inbound SIP trunks. For an explanation of how these components work together, see SIP connectivity. For destination construction, registration behavior, and routing-method selection, see SIP routing methods.

Signaling#

Static Endpoint signaling addresses#

For calls delivered through a Static Endpoint trunk, DIDWW originates SIP signaling from the following addresses.

Location

IPv4 address

IPv6 address

New York

46.19.209.14

2a01:ad00:1:14::14

Frankfurt

46.19.210.14

2a01:ad00:2:14::14

Los Angeles

46.19.212.14

2a01:ad00:4:14::14

Miami

46.19.213.14

2a01:ad00:5:14::14

Singapore

46.19.214.14

2a01:ad00:6:14::14

Hong Kong

46.19.215.14

2a01:ad00:7:14::14

Amsterdam

185.238.173.14

2a01:ad00:8:14::14

Dynamic Registration registrar addresses#

When using Dynamic Registration, configure the customer system to register to one of the following hostnames. Use sip.didww.com for automatic DNS-based load balancing between locations. Use nyc.sip.didww.com to select New York or ams.sip.didww.com to select Amsterdam.

Hostname

IPv4 address

IPv6 address

sip.didww.com

46.19.209.49

2a01:ad00:1:1::49

185.238.173.49

2a01:ad00:8:1::49

nyc.sip.didww.com

46.19.209.49

2a01:ad00:1:1::49

ams.sip.didww.com

185.238.173.49

2a01:ad00:8:1::49

Network protocol values#

The following IP protocol values are available for a Static Endpoint trunk.

Value

Behavior

IPv4 only

Uses IPv4 exclusively.

IPv6 only

Uses IPv6 exclusively.

Any

Allows either IPv4 or IPv6. This is the default value.

Prefer IPv4 over IPv6

Uses IPv4 when available and falls back to IPv6.

Prefer IPv6 over IPv4

Uses IPv6 when available and falls back to IPv4.

Transport protocol values#

Value

Behavior

UDP

Uses User Datagram Protocol for SIP signaling. This is the default value.

TCP

Uses Transmission Control Protocol for SIP signaling.

TLS

Uses Transport Layer Security to encrypt SIP signaling.

Signaling source ports#

DIDWW originates inbound SIP signaling from the following source ports for both routing methods.

Transport

Source port

Firewall requirement

UDP

5060

Accept UDP signaling from the applicable DIDWW signaling addresses.

TCP or TLS

5070–65535

Accept TCP or TLS signaling from the applicable DIDWW signaling addresses across this dynamic source-port range.

The destination port for Static Endpoint delivery is configured on the trunk. When the Port field is empty, DIDWW uses DNS SRV. See DNS SRV failover.

Authentication#

Routing method

Mechanism

Behavior

Static Endpoint

Optional SIP digest authorization

Enable Authorization makes DIDWW authenticate its INVITE requests with the configured Auth User and Auth Password. From User and From Domain can override the corresponding From header components. See Authorization.

Dynamic Registration

SIP digest registration

The customer system registers with the generated Username and Password. The generated credentials and registrar hostnames are read-only after creation. See View SIP registration credentials.

Media#

RTP source subnets#

DIDWW sends RTP from the following subnets.

IP version

Source subnet

IPv4

46.19.208.0/21

185.238.172.0/22

IPv6

2a01:ad00:1:2::/64

2a01:ad00:1:14::/64

2a01:ad00:2:1::/64

2a01:ad00:2:14::/64

2a01:ad00:4::/64

2a01:ad00:4:14::/64

2a01:ad00:5::/64

2a01:ad00:5:14::/64

2a01:ad00:6::/64

2a01:ad00:6:14::/64

2a01:ad00:7:1::/64

2a01:ad00:7:14::/64

2a01:ad00:8:1::/64

2a01:ad00:8:14::/64

RTP and RTCP ports#

Protocol

Port

Behavior

RTP

1024–65535

DIDWW sends RTP from this port range.

RTCP

RTP port + 1

DIDWW sends and receives RTCP on the port immediately after the RTP port, as recommended by RFC 3550. DIDWW can also receive RTCP on the RTP port when RTCP conflict avoidance payload types 72–76 are used.

Supported codecs#

Option

Type

Description

PCMU

Audio codec

G.711 μ-law audio codec.

PCMA

Audio codec

G.711 A-law audio codec.

G729

Audio codec

G.729 audio codec.

G723

Audio codec

G.723.1 audio codec.

L16

Audio codec

Linear PCM audio codec.

G726-16

Audio codec

G.726 audio codec at the selected bit rate.

G726-24

G726-32

G726-40

G721

Audio codec

G.721 audio codec.

GSM

Audio codec

GSM Full Rate audio codec.

Speex

Audio codec

Speex audio codec.

telephone-event

RTP event payload

RTP payload used for RFC 2833 DTMF events.

By default, PCMU, PCMA, G729, G723, and telephone-event are selected on a new inbound SIP trunk. Codec order determines preference. See Media & DTMF for the trunk configuration fields.

DTMF transport methods#

Method

Content type or payload

Support

RFC 2833

telephone-event RTP payload

Supported for sending and receiving. This is the default send and receive method.

SIP INFO

application/dtmf-relay

Supported for sending and receiving.

application/dtmf

The send and receive methods are configured independently. See DTMF Send Mode values and DTMF Receive Mode values.

Encryption#

Layer

Mechanism

Specification

SIP signaling

TLS

Encrypts SIP signaling between DIDWW and the customer SIP endpoint.

RTP media

SRTP SDES

Encrypts RTP and negotiates keys with SDP Security Descriptions.

SRTP DTLS

Encrypts RTP and negotiates keys with Datagram Transport Layer Security. See RFC 5764.

SRTP ZRTP

Encrypts RTP and negotiates keys with ZRTP.

Note

Encryption applies only to the DIDWW-to-customer call leg. It is not maintained end to end across other call legs.

Configure the media mechanism through SRTP Mode. See SRTP Mode values.

SIP OPTIONS#

DIDWW responds to SIP OPTIONS requests sent to the signaling addresses used for inbound call delivery.

Transport

Response port

Behavior

UDP

5060

DIDWW responds to SIP OPTIONS over UDP.

TCP

5060

DIDWW responds to SIP OPTIONS over TCP.

TLS

5061

DIDWW responds to SIP OPTIONS over TLS.

An OPTIONS response confirms SIP reachability. It does not indicate the processing status of an inbound call.

Firewall and SBC allowlist#

Traffic

Addresses or systems

Requirement

Static Endpoint signaling

Static Endpoint signaling addresses

Allow the signaling addresses for every DIDWW location that can deliver calls to the trunk. With Preferred Server set to Auto, allow all listed addresses.

Dynamic Registration signaling

Dynamic Registration registrar addresses

Permit registration traffic to the selected registrar hostname and its resolved addresses, including the return signaling traffic.

RTP and RTCP

RTP source subnets

Allow the listed media subnets and the 1024–65535 RTP port range.

DNS

Customer-configured DNS resolvers

Permit DNS resolution when a trunk uses a hostname, DNS SRV discovery, or sip.didww.com.

The destination signaling port for a Static Endpoint must also be reachable on the receiving SIP server. For the relationship between these flows, NAT, and trunk settings, see SIP connectivity.

Machine-readable network data#

A machine-readable version of the network data on this page is available as JSON.

voice.json

Use the JSON data to configure and monitor firewall or SBC allowlists without parsing this page.