SIP Protocol Details

This section provides essential details about SIP protocol support, including network and transport protocols, signaling endpoints, failover mechanisms, media encryption, and supported codecs.


Supported Network and Transport Protocols

DIDWW supports SIP signaling over UDP, TCP, and TLS transports. Communication can be established using the following ports: 5060 for UDP/TCP and 5061 for TLS. Both IPv4 and IPv6 are supported as network protocols for signaling and media.

DIDWW supports SIP signaling over the following transport protocols:

  • UDP

  • TCP

  • TLS

Supported Ports:

  • UDP/TCP: Port 5060

  • TLS: Port 5061

Network Protocols:

  • Both IPv4 and IPv6 are supported for SIP signaling and media communication.


Signaling Endpoints

Calls can be sent to any of our load balancers. Each load balancer operates as a redundant cluster with multiple nodes using the same IP address.

DIDWW Signaling Endpoints

Location

DNS A/AAAA Record

LB IPv4 Address

LB IPv6 Address

New York

nyc.us.out.didww.com

46.19.209.44

2a01:ad00:1:1::44

Los Angeles

lac.us.out.didww.com

46.19.212.54

2a01:ad00:4:2::54

Miami

mia.us.out.didww.com

46.19.213.54

2a01:ad00:5:2::54

Frankfurt

fra.eu.out.didww.com

46.19.210.19

2a01:ad00:2:1::19

Amsterdam

ams.eu.out.didww.com

185.238.173.44

2a01:ad00:8:1::44

Singapore

sg.out.didww.com

46.19.214.54

2a01:ad00:6:2::54

Hong Kong

hk.out.didww.com

46.19.215.44

2a01:ad00:7:1::44

DNS SRV

DNS SRV is a failover mechanism used to reroute calls to a backup data center in case of a failure.

Recommendation:

  • We recommend enabling DNS SRV if it is supported by your equipment.

  • This ensures high availability and improves redundancy for call routing.

DNS SRV Records

The following table lists the DNS SRV records, including their priority, weight, IP addresses, and roles.

DNS SRV record

Priority

Weight

LB IPv4 address

LB IPv6 address

LB Location

Role

nyc.us.out.didww.com

10

10

46.19.209.44

2a01:ad00:1:1::44

New York

Primary

20

10

46.19.213.54

2a01:ad00:5:2::54

Miami

Backup

lac.us.out.didww.com

10

10

46.19.212.54

2a01:ad00:4:2::54

Los Angeles

Primary

20

10

46.19.213.54

2a01:ad00:5:2::54

Miami

Backup

mia.us.out.didww.com

10

10

46.19.213.54

2a01:ad00:5:2::54

Miami

Primary

20

10

46.19.209.44

2a01:ad00:1:1::44

New York

Backup

fra.eu.out.didww.com

10

10

46.19.210.19

2a01:ad00:2:1::19

Frankfurt

Primary

20

10

185.238.173.44

2a01:ad00:8:1::44

Amsterdam

Backup

ams.eu.out.didww.com

10

10

185.238.173.44

2a01:ad00:8:1::44

Amsterdam

Primary

20

10

46.19.210.19

2a01:ad00:2:1::19

Frankfurt

Backup

sg.out.didww.com

10

10

46.19.214.54

2a01:ad00:6:2::54

Singapore

Primary

20

10

46.19.215.44

2a01:ad00:7:1::44

Hong Kong

Backup

hk.out.didww.com

10

10

46.19.215.44

2a01:ad00:7:1::44

Hong Kong

Primary

20

10

46.19.214.54

2a01:ad00:6:2::54

Singapore

Backup

BGP Anycast

DIDWW provides a BGP Anycast signaling endpoint at any.out.didww.com (185.238.172.4).

Key Features:

  • The anycast prefix 185.238.172.0/24 is announced from all DIDWW Points of Presence.

  • The BGP protocol automatically determines the best path based on customer AS connectivity.

Warning

  • The optimal BGP path may not always provide the best latency or call quality.

  • It is advised to test the anycast endpoint in your environment before using it in production.

Note

  • UDP transport is recommended for the any.out.didww.com endpoint, as it provides better performance for UDP-based services.


RTP and RTCP Information

DIDWW uses the following subnets and ports for RTP (Real-time Transport Protocol) traffic:

IP Subnets for RTP Traffic:

  • 46.19.208.0/21

  • 185.238.172.0/22

RTP and RTCP Port Range:

  • RTP port range: 16383 - 32767

  • RTCP (Real-time Transport Control Protocol) usage: - RTP port + 1 is used for RTCP sending/receiving.


Encryption

Our system supports TLS for secure SIP signaling transport and SRTP for media encryption.

Supported SRTP Key Negotiation Mechanisms:

Warning

  • SRTP media encryption is disabled by default.

  • To enable SRTP support for your account, please contact our sales team at sales@didww.com.


Codecs

The following audio codecs are supported:

  • G.711 (A-law / µ-law)

  • G.729

  • G.723.1

  • GSM

  • telephone-event (DTMF)


P-Charge-Info Header

The P-Charge-Info header allows customers to append additional technical and billing-related information to Call Detail Records (CDRs). This header follows the specifications described in the IETF Draft.

Key Features:

  • The P-Charge-Info value is stored in the CDR for future reference.

  • This data can be used for billing purposes and integrated with the CDR Streaming Tool.

  • Header value format is optional, allowing flexibility in implementation.


SIP Registration Mechanism

The SIP Registration mechanism is not used and not required for this service.

  • The system will respond to REGISTER requests only for compatibility reasons.

  • However, location information from SIP registrations is not utilized within this service.


SIP OPTIONS

Our load balancer automatically responds to incoming SIP OPTIONS requests.

Key Recommendations:

  • We recommend using SIP OPTIONS to monitor connectivity with our system.

  • This mechanism provides a lightweight way to check system availability and reachability.