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To allow Direct Media between NAT devices, or between NAT and Non-NAT devices, the following configuration is necessary.

Direct Media with NAT will not work under following conditions:

  • If the addressContext name of both the endpoints does not match.
  • If the call is a Lawful Intercepted call.
  • If Direct Media Group ID's do not match, directMediaGroupId should be same on both the Trunk Groups.

Configuring Direct Media Between Endpoints Behind the Same NAT

ACCESS SIDE:

  • At Sip Trunk Group Level
    • directMediaAllowed enabled
    • directMediaAllowedBehindNat enabled
  • At Packet Service Profile Level
    •  useDirectMedia enabled

CORE SIDE (towards Application Server):

  • At IPSP Level
    • sendDirectMediaInfoInSdpAttribute enabled
  • At Packet Service Profile Level
    • useDirectMedia enabled

The dmNatPrefix table is not required to create as the endpoints are behind the same NAT.

Configuring Direct Media Between Endpoints Behind the Different NAT

 ACCESS SIDE:

  • At Sip Trunk Group Level
    • directMediaAllowed enabled
    • directMediaAllowedBehindNat enabled
    • sdpTransparencyState disabled
  • At Packet Service Profile Level
    • useDirectMedia enabled

CORE SIDE (towards Application Server):

  • At IPSP Level
    • sendDirectMediaInfoInSdpAttribute enabled
  • At Packet Service Profile Level
    • useDirectMedia enabled
  • At Address Context Level
    • Creating the table dmNatPrefix on addressContext
    • Adding the signaling IP Address of NAT Box, which can have direct media among them.

Configuring Direct Media Between Endpoints Behind the NAT and Non-NAT Endpoint

This is an occasional scenario where an endpoint behind NAT can have Direct Media with endpoint not behind NAT. However, if such a case exists, SBC exchanges the media IPs of such devices, while the actual exchange of media depends on the network.

ACCESS SIDE:

  • At Sip Trunk Group Level
    • directMediaAllowed enabled
    • directMediaAllowedBehindNat enabled
    • sdpTransparencyState disabled
  • At Packet Service Profile Level
    • useDirectMedia enabled

CORE SIDE (towards Application Server):

  • At IPSP Level
    • sendDirectMediaInfoInSdpAttribute enabled
  • At Packet Service Profile Level
    • useDirectMedia enabled
  • At Address Context Level:
    • Creating dmNatPrefix on addressContext
    • Adding signaling IP Address of,
      • NAT Box
      • Endpoint signaling IP not behind NAT.

The CLI syntax to enable Direct Media with NAPT on Trunk Group is as follows:

% set addressContext <name> zone <name> sipTrunkGroup <TG-Name> media directMediaAllowedBehindNapt <disable|enable>

The CLI syntax to group the endpoint signaling IP addresses for which to allow Direct Media with NAPT is as follows:

set addressContext <name> natDirectMediaGroup <groupName> dmNatPrefix <IpV4_Address> <prefixLen>