# General SIP Information

## SIP Signaling Addresses

DIDWW may originate inbound calls to your SIP endpoint using two delivery methods:

- **Static SIP URI**
- **SIP Registration**

Each method uses different SIP endpoints.

### Static SIP URI

When forwarding calls to your equipment using a **static SIP URI**, calls will originate from the following DIDWW SIP
endpoints:

| 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 |

### SIP Registrars

When using **SIP Registration** to dynamically register your SIP trunk, configure your system to register to one of the
following DIDWW SIP registrar hostnames.

Use `sip.didww.com` for automatic DNS-based load balancing between locations, or select a regional hostname to force
registration to a specific location.

| Host | 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 |

## SIP Signaling Source Ports

DIDWW originates inbound SIP signaling using the following **source ports**, regardless of whether SIP URI delivery or
SIP Registration is used:

- **UDP:** source port `5060`
- **TCP / TLS:** dynamic source ports `5070-65535`

Ensure that your firewall or SBC allows SIP signaling from the DIDWW signaling IP addresses listed in the sections
above.

## RTP addresses

Our system sends RTP packets from the following subnets:

- 46.19.208.0/21
- 185.238.172.0/22
- 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

with RTP port-range: 1024-65535

## RTCP

We transmit and receive RTCP packets from port = rtp\_port + 1 (as recommended in
[RFC3550](https://tools.ietf.org/html/rfc3550#section-11)).
Additionally, we are able to receive RTCP packets on the same port as RTP, considering utilizing RTCP conflicts
avoidance payloads (payload types 72-76).

## SIP OPTIONS

DIDWW is responding on SIP OPTIONS while sending requests to signaling IPs. It will respond on UDP 5060, TCP 5060 and
TLS 5061 ports.

Please note that SIP OPTIONS responses are not related to call processing.

## Encryption

Our system supports **TLS** for secure **SIP signaling transport** and
[SRTP](https://en.wikipedia.org/wiki/Secure_Real-time_Transport_Protocol) for media encryption.

Supported SRTP key negotiation mechanisms:
:   - [SDES](https://en.wikipedia.org/wiki/SDES)
    - [DTLS](https://tools.ietf.org/html/rfc5764)
    - [ZRTP](https://en.wikipedia.org/wiki/ZRTP)

Note

- Encryption applies only to the **DIDWW ↔ Customer** call leg. Encryption is not maintained end-to-end, and any other call legs outside this connection are not encrypted.

## Supported codecs

> | Option | Description |
> | --- | --- |
> | **PCMU** | G.711 μ-law audio codec. |
> | **PCMA** | G.711 A-law audio codec. |
> | **G729** | G.729 audio codec. |
> | **G723** | G.723.1 audio codec. |
> | **L16** | Linear PCM audio codec. |
> | **G726-16**, **G726-24**, **G726-32**, **G726-40** | G.726 audio codec at the selected bit rate. |
> | **G721** | G.721 audio codec. |
> | **GSM** | GSM Full Rate audio codec. |
> | **Speex** | Speex audio codec. |
> | **telephone-event** | RTP payload used for RFC 2833 DTMF events. |

## DTMF transport methods

DTMF signaling is supported as follows:

- Telephone-event [RFC2833](https://tools.ietf.org/html/rfc2833)
- SIP INFO [draft-kaplan-dispatch-info-dtmf-package-00](https://tools.ietf.org/html/draft-kaplan-dispatch-info-dtmf-package-00)

  > - application/dtmf-relay
  > - application/dtmf

By default RFC 2833 enabled

## Machine-readable network data

A machine-readable version of this page's network data is available as JSON:

[voice.json](/voice.json)

Use it to programmatically configure and monitor firewall or SBC allowlists,
instead of parsing this page.

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