Skip to content

SIP Gateway

The NUC acts as a SIP gateway between the Tata PSTN trunk (NNI) and the Astradial cloud PBX. This page covers the Tata interconnect details and trunk behavior.

Tata NNI Details

Parameter Value
VLAN 1922
Customer IP 10.54.225.90/30
Gateway 10.54.225.89
SBC IP 10.79.215.102
Media Pool 1 10.79.167.0/28
Media Pool 2 10.79.167.48/28

DID Range

Parameter Value
Range start +918065978000
Range end +918065978029
Total DIDs 30
Channels 10 (concurrent calls)

Authentication

The trunk operates in NNI mode with IP-based authentication. There is no SIP registration involved.

  • Tata identifies the NUC by its source IP (10.54.225.90).
  • The NUC identifies Tata by the SBC IP (10.79.215.102).
  • No username/password credentials are exchanged.

Call Flow

Inbound (PSTN to Cloud)

Tata SBC (10.79.215.102)
    |
    | SIP INVITE (+918065978XXX)
    v
NUC Asterisk (10.54.225.90)
    Context: from-tata
    Action: Dial(PJSIP/cloud-endpoint)
    |
    | via WireGuard tunnel
    v
Cloud Asterisk (10.10.10.1)
    Context: tata-inbound
    Action: Route DID to organization

Outbound (Cloud to PSTN)

Cloud Asterisk (10.10.10.1)
    |
    | via WireGuard tunnel
    v
NUC Asterisk (10.10.10.2)
    Context: from-cloud
    Action: Dial(PJSIP/tata-endpoint)
    |
    v
Tata SBC (10.79.215.102)
    |
    v
PSTN

Known Behaviors

Tata does not respond to SIP OPTIONS

The Tata SBC does not reply to SIP OPTIONS (qualify) messages. As a result, the tata-endpoint will always show as Unavailable in pjsip show endpoints. This is expected behavior -- the trunk works normally for actual calls despite the Unavailable status.

The NUC Asterisk config sets qualify_frequency=0 on the Tata AOR to avoid sending OPTIONS at all.

Media Routing

RTP media from Tata can originate from either media pool:

  • 10.79.167.0/28 (10.79.167.1 -- 10.79.167.14)
  • 10.79.167.48/28 (10.79.167.49 -- 10.79.167.62)

Ensure that any firewall rules on the NUC allow UDP traffic from these ranges for RTP.