External Gateway

An external gateway can be any type of VoIP network element that sends and receives SIP messaging. The External Gateway can be a SIP Gateway, another IMG 2020, an IP Phone, etc. The IMG 2020 can be configured to communicate with up to 1024 external SIP Gateways. This is accomplished using the External Gateway object. Within the External Gateway object are all the fields needed to communicate with an External SIP Gateway. To create the External Gateway object, right click on the External Gateways object and select New External Gateway.

Configuring multiple endpoints with the same IP address even if the port numbers are different could result in incorrect routing for incoming calls to the IMG 2020.

Web GUI Page

Dialogic > External Network Elements > External Gateways > New External Gateway

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Related Topics and Dependencies

The SIP External Gateway object is considered an element of the IP network. Therefore the External Network Elements object must first be created. Under the External Network Element object the External Gateways object is created which allows up to 1024 individual gateways to be configured under it.

Within the External Gateway object is a field labeled SIP Profile. There must be at least one SIP Profile object created under the Profiles object to populate this field.

Once the External SIP Gateway has been configured the IMG 2020 needs to connect to the Gateway. This is done using the SIP Channel Group object. Right Click on the SIP Channel Group and select New IP Network Element. Select the External Gateway from drop down menu in this object.

External Gateways

External Network Elements

IP Network Element

Configure SIP (Single SIP IP)

Configure SIP (Multiple SIP IP)

Channel Group

Maximum Objects

Up to 1024 External SIP Gateways can be configured to communicate with IMG 2020.

Field Descriptions

Name

The Name field identifies the specific external gateway being configured. Click in the Name field and enter a name that identifies the gateway.

Protocol

The Gateway Signaling Protocol field configures what type of signaling will be needed to communicate with the External Gateway. The IMG 2020 supports both the SIP and H.323 protocol.

SIP- The external gateway that the IMG 2020 will communicate with uses the SIP protocol for signaling.

H.323- The external gateway the IMG 2020 will communicate with uses the H.323 protocol for signaling.

Address Type

When transmitting and receiving SIP messaging the IMG 2020 can use either the IP address of the gateway or the host name of the gateway. Select from drop down menu one of the two selections below. Depending on which selection is made, the SIP messaging will include either the Gateway IP address or Gateway Host Name.

IP Address (default) -  The External Gateway being configured is identified by use of IP address. This enables an IP address to be entered into the Gateway IP address field below.

Host Name (SIP only) - The External Gateway being configured is identified using host name and domain. For example: (gw1.dialogic.com). This enables a host name to be entered into the Gateway Host Name field below. (IPV4)

IP Type

The IMG 2020 supports both the IPv4 and IPv6 protocols. Select from the drop down menu which Internet Protocol Version will be required.

IPv4 (Internet Protocol Version 4) (Default) – When IPv4 is selected, the Internet Protocol Version 4 format will be utilized. All IP addresses and Network Prefix fields in this object will require entering values using IPV4.

IPv6 (Internet Protocol Version 6) - When IPv6 is selected, the Internet Protocol Version 6 format will be utilized. All IP addresses and Network Prefix fields in this object will require entering values using IPv6. IPv6 is supported when configuring SIP Signaling and its accompanying RTP Media or Video packets. IPv6 is Not Supported when utilizing H.323 Signaling.

IP Address

If the Address Type field above is set to IP Address, click in the IP Address field and enter the IP address of the external gateway that the IMG 2020 is communicating with. If the Address Type field above is set to Host Name, ignore this field.

Allowed Gateway Subnet Prefix  

Use this field to configure the IMG 2020 to accept calls from multiple gateways with one entry. The value entered in the Allowed Gateway Subnet Prefix field in conjunction with the value entered in the IP Address field determines the range of IP Addresses from which the IMG 2020 will accept any calls. If the Incoming IP Address equals one of the IP Addresses in the range set up then the call will be processed. The allowed values in the Allowed Gateway Subnet Prefix field range from 0 to 32. The table below displays examples for the most common Subnet Prefixes for a specific IP address. A Subnet Calculator such as the ip subnet calculator can be used if required to determine the range of IP Addresses etc. For more information on the subnet prefix field, refer to the IPv6 / IPv4 Overview topic.

Host Name

If the Gateway Address Type field above is set to Host Name, click in the Host Name field and enter the host name of the external gateway that the IMG 2020 is communicating with. If the Address Type field above is set to Gateway IP Address, ignore this field.

Transport Type

The Gateway Transport Type specifies the transport layer protocol that will be used to communicate with the external gateway being configured. The three protocols supported are Transmission Control Protocol (TCP), User Datagram Protocol (UDP), and Transport Layer Security (TLS). Select from the drop down menu which protocol will be utilized.

UDP (Default)- Use User Datagram Protocol to communicate with the external gateway.

TCP  - Use Transmission Control Protocol to communicate with the external gateway.

TLS- Use Transport Layer Security encryption on top of TCP. If TLS is selected, the Secure Profile field below will no longer be shaded green and can now be modified. Refer to the Secure Profile field below.

Transport Port

The IMG 2020 will communicate with the external gateway using an IP address and port number. Enter the port number that the external gateway will use to transmit and receive SIP messaging from. The Default Port is set to 5060 which is commonly used for the TCP and UDP protocols. If TLS is being configured, then typically the port number used is port 5061. To modify the Gateway Remote Port, click in the field and enter a new port number.

Registration Required

This field indicates if the IMG 2020 must register with the external gateway.

The credential used for registration on reboot are the ones from the SIP Network Element, if tied to an external gateway. Otherwise the credentials used in the registration are the ones specified in the SIP object.

No (Default) - IMG 2020 will not need to register with external gateway.

Yes - IMG 2020 will need to register with external gateway.

Registration Interval (sec)

Use the Registration Expiration Interval field to control the registration refresh interval. To modify, highlight the number in the Seconds box and enter a new value.

Default = 3600 second

Range = 10-7200 seconds

Profile

When communicating with an external SIP gateway, each SIP Gateway could have a different set of attributes that the IMG 2020 needs to configure to be able to successfully communicate with each gateway. These attributes are configured in the SIP Profile (SGP) object. Once the SIP Profiles (SGP) are configured, each profile can be associated with a different gateway by selecting it in the drop down menu of the SIP Profile object. See SIP Profile - SGP for more information.

Secure Profile

If Transport Layer Security (TLS) is going to be utilized, a Secure Profile must be configured. Any Secure Profiles created will be displayed in the drop down menu of the Secure Profile field. Select the Secure Profile to be assigned to the external gateway that the IMG 2020 will be communicating with. See Secure Profile for more information.

OPTIONS Keep Alive

Use his field to enable the SIP Options Keep Alive (Busy Out) feature on an external gateway.

Enable - With this field set to enable the IMG 2020 will send periodic SIP OPTIONS messages. If the gateway does not respond to one OPTIONS message the gateway will be considered down or unreachable and attempt to re-route the call to a different gateway.

Disable (default) - The SIP options Keep Alive feature will be disabled.

OPTIONS Keep Alive Status

This monitoring field contains the status of the SIP OPTIONS Keep Alive. Possible values are Not Available, Unreachable or Reachable.

For more information on the SIP Options message refer to the SIP Profile - Options Method - Busy Out-Keep Alive or SIP Options - Busy Out/Keep Alive Configure topics for more information.