Galaxy Expand – Reference Architecture

The Galaxy Expand is a hardware platform  that is part of the E-MetroTel overall server portfolio.  While it can function as a Call Server platform; with a variety of Call Processor configuration options for standalone operation, it can also be configured with an active/standby pair of call processors across two chassis for High Availability (HA), with a single processor for Survivable Remote Gateway (SRG) operation, or even with no Call Processors for a highly compact, large scale FXO, FXS, PRI, or Digital Station gateway.

One or more Galaxy Expand platforms can be deployed in an enterprise network, typically connected to other Galaxy, UCX, or other third party systems through a combination of SIP or PSTN interfaces.

Galaxy Expand Reference Architecture

The following diagram depicts the many different methods of deployment of the Galaxy Expand platform across different enterprise locations.

Headquarters Deployment

In a enterprise headquarters location, the Galaxy Expand platform can be configured to serve multiple uses depending on the specific needs of both the headquarter office and those of the rest of the corporate network.

Primary Call Server

At the enterprise headquarters, the primary configuration of a Galaxy Expand system will be as a Call Server running E-MetroTel UCx software. This configuration requires a server card – either a Galaxy i5 Server Card or a Galaxy 2930 Server Card, depending on the expected number of registered extensions and/or concurrent calls.(Refer to the component table in Galaxy Expand – Platform Overview and Hardware.)

Expansion shelves

The system can have any number of Telephony Interface cards in the remaining 10 slots. If additional Telephony Interface cards are required, addition Galaxy Expand chassis can be deployed without requiring additional Server Cards for standalone system operation.

Redundant or Active/Standby Server

If redundant or active/standby functionality is required, a Galaxy Server card can be deployed in any of the available slots in either of the two separate chassis. Both server cards must be the same, and the High Availability Redundant Configuration (HARC) license is required per the High Availability (HARC)  documentation.


The two Galaxy Expand Chassis configurations are not required to be identical since the supported telephony interface cards (PRI, DSM16, and FSX16) cards connect via IP interfaces Dahdi-based cards are not supported in HARC mode.

InfinityOne Server

Some enterprise deployments may wish to off-load the InfinityOne server functionality from the main UCX software call processing. In this scenario, one chassis would be deployed as the primary call processing server, and a Galaxy 2930 Server Card could be placed on a separate chassis and configured to run the InfinityOne application.  

Remote Gateway Deployment

If there are locations within the enterprise where digital extensions are required, the Galaxy Expand chassis can be configured as a gateway platform that can be configured with up to eleven (11) DSM16 cards for a total of 176 digital extensions. Multiple Galaxy Expand chassis can be deployed at a single location and across an enterprise network as long as the total number of registered extensions and concurrent calls is within the processing limits of the ​Galaxy Server card at the headquarters location.

Survivable Remote Gateway Deployment

The Galaxy Expand is well suited to being deployed as a Survivable Remote Gateway (SRG).  In this case a server card would be required in order to provide the local call processing for survivable operation.  The remaining slots on the Galaxy Expand chassis could be used for connecting digital or analog extensions or digital (PRI) or analog lines/trunks.