FXS Configuration for IP PBX Deployment

The following example demonstrates a complete FXS to IP PBX deployment using an Edge 8300 model and the Edge 8000 Series 24.0 software release. The example includes screenshots and specific values for all the major configuration areas of the deployment:

• Setup Wizard
• Licensing
• SWe Edge provisioning
• SIP User Agent provisioning for FXS ports

For the entire provisioning process, including physically Installing Edge 8000 Hardware, refer to Workflow for Initial Setup.

While the goal of this example is not to provide a detailed configuration that meets the needs of every deployment scenario, it does provide a starting point for building your own customized configuration for an FXS to IP PBX deployment.

Contents

Network and Call Flow Diagrams

In this demonstration, an Edge 8300 is configured to support two signaling groups:

• On the analog side, an FXS port connected to an analog phone
• On the private or LAN side, an IP PBX with VLAN logical sub-interfaces connected to an IP phone

The following diagrams depict the deployment topology, network interfaces, and call flows for this demonstration.

Deployment Topology

Network Interfaces

Signaling and Media Call Flows

Setup Wizard Values

After physically installing the device, the deployment team uses the Edge 8000 Setup Wizard to establish basic platform settings.

The following tables show the values entered in Setup Wizard for this FXS to SIP IP PBX demonstration. Consult your network design and deployment teams for the specific values appropriate for your network.

System Configuration

Bridge Settings (BR1-4)

Gigabit Ethernet Settings (GE1-8)

Small Form-factor Pluggable (SFP9-10)

Default Gateway

DNS Settings

Swe-Edge Settings

SWe Edge License and Analog License Features

In this demonstration, the Edge 8300 device requires SWe Edge and Analog licenses.

To view the SWe Edge license features, log in to the SBC SWe Edge WebUI as user admin, click the Settings tab, and navigate to Licensing > Current Licenses.

The following screenshot illustrates the SWe Edge license features used in this demonstration.

SWe Edge License Features

To view the Analog license features, log in to the Edge 8000 WebUI as user admin and select License in the navigation pane.

The following screenshot illustrates the Analog license features used in this demonstration. (The Router license, which is standard on all Edge 8000 devices, also appears on this screen.)

Analog License Features

SWe Edge Configuration

Network Interface Values

Network Interfaces define the way the SBC SWe Edge operates within the Edge 8000 to communicate with the external network.

The Edge 8000 supports system-created logical interfaces known as Administrative IP, Ethernet 1 IP, Ethernet 2 IP, and Ethernet 3 IP for the SWe Edge function. In addition, the Edge 8000 supports user-created VLAN logical sub-interfaces.

In this demonstration,

• The Admin IP is set as the Mgmt Host IP in the Swe-Edge Settings of the Setup Wizard 
• The following IP addresses are not set during the Setup Wizard and must be entered manually:
  • the Ethernet 1 IP address, which provides a connection to the LAN IP PBX
  • the Ethernet 1.2626 IP address, which supports a connection to a VLAN logical sub-interface to the LAN IP PBX
  • the Ethernet 2 IP address, which provides an internal logical SWe Edge connection to the analog port
• The Ethernet 3 IP interface is not used

For this demonstration, the following Network Interface values have been assigned:

Network Interface Assignments

To display Network Interfaces in the SWe Edge WebUI:

• click the Settings tab
• navigate to Networking Interfaces > Logical Interfaces

The following screenshots illustrate the Network Interfaces defined for this demonstration.

Network Interfaces

Example of a Network Interface: Ethernet 1.2626 IP

Static Route Values

• For smaller networks with just one or two routes, configuring static routing is preferable. This is often more efficient since a link is not being wasted by exchanging dynamic routing information.
• For networks that have a LAN-side gateway on Voice VLAN or Multi-Switch Edge Devices (MSEs) with voice VLAN towards the SBC Edge, static routing configurations are not required.

Two Static Routes are defined for this demonstration:

• The first Static Route gives access to the SWe Edge WebUI on a management computer through a VPN subnet.
  
• The second Static Route gives access to the IP PBX.

Static Route fields include:

• Destination IP – Specifies the destination IP address.
• Mask – Specifies the network mask of the destination host or subnet. (If the 'Destination IP Address' field and 'Mask' field are both 0.0.0.0, the static route is called the 'default static route'.)
• Gateway – Specifies the IP address of the next-hop router to use for this static route.

To display Static Routes in the SWe Edge WebUI:

• click the Settings tab
• navigate to Protocols > IP > Static Routes

The following screenshot illustrates the Static Routes defined for this demonstration.

Static Routes

Signaling Groups

Signaling groups allow telephony channels to be grouped together for routing and shared configuration purposes. They are the locations from which ingress calls enter and to which egress calls are routed out. They are also the location from which Tone Tables are selected. In the case of SIP, they specify protocol settings and are linked to server, media, and mapping tables.

As an aid to understanding, the following diagram depicts a typical call flow sequence. Every call enters through an ingress Signaling Group, traverses through a Call Routing Table and its associated Transformation Table or Tables, and exits through an egress Signaling Group. A SIP Server Table or Local Registrar defines for each Signaling Group where the call should go on egress.

SIP to SIP Call Flow Sequence

Two Signaling Groups are defined for this demonstration:

• To/From IP PBX Signaling Group – serves the LAN-side IP PBX and associated IP phones
• To/From FXS Signaling Group – serves the analog-side FXS ports and associated analog phones
  

The following fields of each Signaling Group must be modified as a minimum per your deployment plan:

• SIP Profile
• Tone Table
• Call Routing Table
• SIP Mode
• SIP server table / Local Registrar
• Media List ID
• Signaling/Media Source IP
  
• Listen Ports
• Federated IP/FQDN
  

Additional fields may be modified per end-user requirements.

To display Signaling Groups in the SWe Edge WebUI:

• click the Settings tab
• navigate to Signaling Groups

The following screenshots illustrate the Signaling Groups defined for this demonstration.

To/From IP PBX Signaling Group

To/From FXS Signaling Group

SIP Profiles

SIP Profiles control how the Edge 8000 device communicates with other SIP devices. SIP Profiles control important characteristics such as session timers, SIP header customization, SIP timers, MIME payloads, and option tags.

In this demonstration, two SIP Profiles are defined, one for each Signaling Group:

• To/From IP PBX Profile – serves the To/From IP PBX Signaling Group
• Default SIP Profile – serves the To/From FXS Signaling Group
  

To display SIP Profiles in the SWe Edge WebUI:

• click the Settings tab
• navigate to SIP > SIP Profiles

The following screenshots illustrate the SIP Profiles defined for this demonstration.

To/From IP PBX Profile

Default SIP Profile

Tone Tables

Tone Tables allow the Edge 8000 administrator to customize the tones a user hears when placing a call. You can modify the tone to match your local PSTN or PBX. The default Tone Table is configured for the values used in the United States for the following categories: Ringback, Dial, Busy, Congestion, Call Waiting, Disconnect, and Confirmation.

In this demonstration, each Signaling Group uses a unique Tone Table:

• United States Tone Table – serves the To/From IP PBX Signaling Group
• Default Tone Table – serves the To/From FXS Signaling Group
  

To display Tone Tables and associated profiles in the SWe Edge WebUI:

• click the Settings tab
• navigate to Tone Tables
  

The following screenshots illustrate the Tone Table and associated Tone Profiles defined for this demonstration.

United States Tone Table

Default Tone Table

Ringback Tone Profile

Congestion Tone Profile

Transformation Tables

Transformation Tables facilitate the conversion of names, numbers, and other fields when routing a call. They can, for example, convert a public PSTN number into a private extension number or into a SIP address (URI). Every entry in a Call Routing Table requires a Transformation Table.

In this demonstration, two Transformation Tables are defined:

• Transformation Table, IP PBX Numbers
  • supports the Call Routing Table, From IP PBX
  • matches the telephone number ranges of the IP phones
    
• Transformation Table, FXS Numbers
  • supports the Call Routing Table, From FXS
  • matches the telephone number ranges of the analog phones
    

To display Transformation Tables in the SWe Edge WebUI:

• click the Settings tab
• navigate to Call Routing > Transformation

The following screenshots illustrate the Transformation Tables defined for this demonstration.

Transformation Table – IP PBX Numbers 

Transformation Table – FXS Numbers

Call Routing Tables

Call Routing Tables allow calls to be carried between signaling groups, thus allowing calls to be carried between ports and between protocols. Call Routing Tables define routes, which allow for flexible configuration of which calls are carried and how they are translated. These tables are one of the central connection points of the system, linking Transformation Tables, Message Translations, Cause Code Reroute Tables, Media Lists, and the Signaling Groups.

Each Signaling Group has one Call Routing Table. In this demonstration, two Signaling Groups, each with its own Call Routing Table, are defined:

Signaling Group and Matching Call Routing Table

The following fields of the Call Routing Table must be modified as a minimum:

• Number/Name Transformation Table
• Destination Signaling Groups

Additional fields may be modified per end-user requirements.

To display Call Routing Tables in the SWe Edge WebUI:

• click the Settings tab
• navigate to Call Routing > Call Routing Table

The following screenshots show the two Call Routing Tables and the entry in each table. Each entry specifies a different Transformation Table. 

Call Routing Table – From IP PBX 

Entry – To FXS

Call Routing Table – From FXS

Entry – To IP PBX 

SIP Server Tables

SIP Server tables contain the IP address or FQDN of one or more SIP servers where INVITE messages can be sent to egress calls on a Signaling Group. The entries in the tables provide information about the IP Addresses, ports, and protocols used to communicate with the servers. The entries also contain links to counters that are useful for troubleshooting.

In this demonstration, one SIP Server Table, IP PBX, serves the To/From IP PBX Signaling Group.

The following fields of the SIP Server Table must be modified as a minimum:

• Host FQDN/IP
• Port
• Protocol

Additional fields may be modified per end-user requirements.

To display SIP Server Tables in the SWe Edge WebUI:

• click the Settings tab
• navigate to SIP > SIP Server Tables
  

The following screenshot shows the SIP Server Table, IP PBX, created for this demonstration. 

SIP Server Table – IP PBX

Local Registrar 

SIP provides a registration function that allows IP phone users to upload their current location for use by proxy servers. Registration creates a binding in a location service for a particular domain that associate an address-of-record URI with one or more contact addresses.

Registration entails sending a REGISTER request to a special type of UAS (User-Agent Server) known as a registrar. A registrar acts as the front end to the location service for a domain, reading and writing mappings based on the contents of REGISTER requests. This location service is then typically consulted by a proxy server that is responsible for routing requests for that domain.

In this demonstration, one SIP Local Registrar Table is defined.

The following field of a Local Registrar Table must be defined as a minimum:

• Maximum Number of Users

Additional fields may be modified per end-user requirements.

To display Local Registrars in the SWe Edge WebUI:

• click the Settings tab
• navigate to SIP > Local Registrars
  

The following screenshot shows the FXS SIP Registrar local registrar associated with the To/From FXS Signaling Group in this demonstration.

FXS SIP Registrar

Media Profiles

Media Profiles allow you to specify individual voice and fax compression codecs and their associated settings for inclusion in a Media List. Different codecs provide varying levels of compression, allowing a tradeoff between reducing bandwidth at the expense of reducing voice quality.

The following field of a Media Profile must be modified as a minimum:

• Codec

Additional fields may be modified per end-user requirements.

To display Media Profiles in the SWe Edge WebUI:

• click the Settings tab
• navigate to Media > Media Profiles

The following screenshots show the Media Profiles created for this demonstration.

IP PBX: G.711 A-Law

IP PBX: G.711 Mu-Law

IP PBX: G.729

Default G.711 A-Law

Default G.711 Mu-Law

Media Lists

A Media List contains a list of media profiles you order to give preference to more desirable codecs above less desirable ones. Profile order determines the order in which codecs are specified in SIP message(s) sent to a peer.

The following field of a Media List must be modified as a minimum:

• Media Profiles List

Additional fields may be modified per end-user requirements.

To display Media Lists in the SWe Edge WebUI: 

• click the Settings tab
• navigate to Media > Media List

The following screenshots show the two Media Lists created for this demonstration:

• IP PBX List associated with the To/From IP PBX Signaling Group
• Default Media List associated with the To/From FXS Signaling Group

IP PBX List

Default Media List

SIP User Agent Configuration

In order to make calls from analog phones through FXS ports, the ports must be configured with SIP User Agent (SIP UA) parameters using the Edge 8000 Analog Manager.

Log in to the Edge 8000 webUI as user admin to access the Analog Manager.

The Analog Manager allows you to set SIP User Agent global and port-level parameters that FXS ports require for making analog calls.

Global SIP UA Settings

To display the SIP UA global settings in the Edge 8000 WebUI:

• click the Analog menu 
  
• navigate to SIP-User-Agent > UA-Settings > Global-Configuration

SIP User Agent – Global Configuration

The following parameters must be modified as a minimum for the SIP UA Global Configuration:

Minimum Global Configuration Settings for the SIP User Agent 

Port-Level SIP UA Settings

To display the SIP UA port-level settings in the Edge 8000 WebUI:

• click the Analog menu 
  
• navigate to SIP-User-Agent > UA-Settings > Port-Level-Configuration

SIP User Agent – Port-Level Configuration

The following parameters must be modified as a minimum for the SIP UA Port-Level Configuration:

Minimum Port-Level Configuration Settings for the SIP User Agent