External Gateway

An external gateway can be any type of VoIP network element that sends and receives IP messaging. The External Gateway can be a SIP Gateway, an H.323 gatekeeper, another IMG, an IP Phone, etc. The IMG can be configured to communicate with up to 1024 external SIP or H.323 Gateways. This is accomplished using the External Gateway object. Within the External Gateway object are all the fields needed to be able to communicate with an External SIP or H.323 Gateway. To create the External Gateway object, right click on the External Gateways object and select New External Gateway.

Note: 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.

 

Accessing this Pane

IMG EMS > External Network Elements > External Gateways > External Gateway

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Related Topics:

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. To be able to select a SIP Profile from this field, there must be at least one SIP Profile object created under the Profiles object.

Once the External SIP Gateway has been configured the IMG 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
Adding an External Gateway
Configuring SIP

 

Maximum External Gateway Objects:

Up to 1024 external gateways can be configured to communicate with the IMG. Click on Technical Notes link for technical information when configuring the External Gateway.

 

External Gateway Pane 10.5.x + with Transport Type = TLS

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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.

 

Gateway Signaling Protocol

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

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

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

 

Gateway Address Type

When transmitting and receiving SIP messaging the IMG 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 IP messaging will include either the Gateway IP address or Gateway Host Name.

Gateway 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. (IPV4)

Gateway 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)

 

Gateway IP Address

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

 

Gateway Mask

Use this field to configure the IMG to accept calls from multiple gateways with one entry. The Gateway Mask in conjunction with the Gateway IP Address field determines the range of IP Addresses from which the IMG 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. A Subnet Calculator can be used if needed to determine the range of IP Addresses etc.

Note: In regards to outbound calls, only the specific IP address in the Gateway IP Address field is used.

Gateway IP Address Gateway Mask Range of IP Addresses
10.11.12.1 255.255.255.255 (Default) 10.11.12.1
10.11.12.1 255.255.255.128 10.11.12.1 - 10.11.12.126
10.11.12.1 255.255.255.224 10.11.12.1 - 10.11.12.30
10.11.12.1 0.0.0.0 Accepts any legal IP address

 

Gateway Host Name (SIP Only)

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

Note: To look up a gateway based on Host Name, a DNS Server must be configured.

 

Gateway Transport Type

The Gateway Transport Type specifies the transport layer protocol used to communicate with an external SIP gateway. The Gateway Transport Type field set in the External Gateway object in ClientView overrides the initial setting of the Default Transport Type in the SIP Signaling stack object. This flexibility between objects is done so a SIP network can have multiple external gateways communicating with the SIP signaling stack configured on the IMG. If however the external SIP gateway transmits to the IMG a protocol that contrasts what is configured in the Gateway Transport Type field, the IMG will continue the call using the protocol initiated by the external gateway with the exception of TLS. The three protocols supported are Transmission Control Protocol (TCP), User Datagram Protocol (UDP), and Transport Layer Security (TLS). Select from drop down menu which protocol will be utilized.

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

UDP (SIP Only) - Use User Datagram Protocol to communicate with the gateway.

TLS (SIP Only) - Use Transport Layer Security encryption on top of TCP. If TLS is selected, a Secure Profile field will appear. See Secure Profile field below.

 

Note: If the SIP Invite is greater than 1500 bytes TCP -or- TLS is required (UDP will truncate message).

 

Gateway Remote Port

The IMG 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 IP messaging. 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.

 

Gateway Registration Required (SIP Only)

This field indicates if the IMG must register with the external gateway. Applies to SIP Gateways only.

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

Yes - IMG will need to register with external gateway.

 

Registration Expiration Interval (sec) (SIP Only)

Use the Registration Expiration Interval field to control the registration refresh interval. Applies to SIP Gateways only.

Default = 3600 second

Range = 10-7200 seconds

 

SIP Profile

When communicating with an external SIP gateway, each SIP Gateway could have a different set of attributes that the IMG needs to configure to be able to successfully communicate with each gateway. These attributes are configured in the SIP Gateway Profile (SGP). Once the SIP Gateway Profiles 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 SGP Profile for more information.

 

Secure Profile: (10.5.1)

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 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 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.

Note: If the Options Keep Alive property is enabled, disable it before changing other Properties in the SIP External Gateway object. Re-enable it once the other changes have been made. This sequence will insure the IMG is configured correctly.

For more information on the SIP Options message refer to the SIP Options Keep Alive Overview or SIP Options Keep Alive Configure topics for more information.

 

Object Table Tab

The SIP Gateway object table displays all the currently configured External Gateways. Each entry displays information that was configured in the External Gateway object above.