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Overview

The Media System Configuration contains system-wide settings for the Media System; configuring the media system means setting the number of RTP/RTCP port pairs and the starting port. Other aspects of media handling, such as Media Profiles, Lists, and Managing SDES-SRTP Profiles are handled in different UI sections and explained on their own topic pages.

UDP ports are used to transmit VoIP calls employing RTP protocols (RTP over UDP). The start port is the first port that can be used for a call. Calls require a pair of ports, one for the voice and the other for the control information (RTP/RTCP). The number of port pairs determines the number of simultaneous IP Call Legs on the SBC Edge Portfolio (SBC). For example, if you have 100 pairs, you can have a maximum of 100 simultaneous IP Call Legs. This does not affect the number of TDM/TDM calls.


SBC Reserved Ports

Port

Protocol

PortProtocol

1

RAW

500UDP

22

TCP

514

UDP

53TCP4500UDP

80

TCP

30000UDP

161

UDP

30001

UDP

443

TCP

16384 to17583

RTP/RTCP
Note:

If you have 100 pairs, and every call has one IP call leg and one TDM call leg, then you can have 100 calls. However, if a call is IP on the inbound and IP on the outbound leg, then it requires two port pairs, reducing the total number of simultaneous calls accordingly (i.e., maximum of 50 IP/IP calls vs. Max 100 IP/TDM calls).

Port Pair Considerations

For SBC SWe Edge Release 7.0 and later only: The number of RTP Port Pairs must be configured slightly larger than the actual number of ports required to support the projected number of calls. We recommend you over-allocate the number of port pairs by approximately 25 - 30% above the number of calls you want to support.


SBC Reserved Ports - Example

Projected Number of Calls

Approximate Number of Port Pairs

Applies To
100 sessions250Audio calls only *
1000 sessions2500Audio calls only *

* Multiple audio and video stream proxy calls will require twice the number of RTP port pairs with the examples provided above.

How Ping Affects Media

The SBC periodically (approximately every 30 seconds) pings all the media endpoints engaged in calls with the SBC. For local endpoints (that are on the same subnet as the SBC), this ping mechanism is used to refresh the ARP cache in the SBC. The call may have audio issues if a local endpoint does not respond to the pings and the media IP address differs from the signaling IP address.

Configuring the Media System

  1. In the WebUI, click the Settings tab.

  2. In the left navigation pane, go to Media > Media System Configuration.

    SBC Edge - Media System Configuration


    SBC SWe Edge - Media System Configuration

Media System Configuration 

Port Range - Field Definitions

Start Port

Specifies the starting number for the RTP and RTCP port range.

Number of Port Pairs

The number of media port pairs used by the SBC system.

  • For SBC 1000/2000. Valid entry: 1 - 4800.
  • For SBC SWe Edge. Valid entry: 2 - 5000.


To determine the last port number, use the formula: First Port Number + (2*Number of Port pairs) - 1.

Example using starting port number (16384) and the number for port pairs is 600.

There are 600 pairs, meaning there are 1200 individual ports. 16384 + (1200-1) = 17583

Regular Call Media Port Range

Specifies a range available for non-Teams (ICE-LITE disabled) call legs.

ICE Call Media Port Range 

Specifies a range available for MS Teams call legs when ICE-LITE is enabled.

When a SBC1K/2K is configured for Teams and if it is behind a firewall, the firewall must open both the port ranges.

Note

ICE Call Media Port Range is used only by SBC1K/2K. 


Music on Hold - Field Definitions

Music on Hold Source

Specifies the audio source. Sources can be an uploaded music file (File) or live audio sourced from an FXS port (Live). Default option is File. If you select Live, the FXS Port option is displayed.

When uploading a Music file, the maximum file sizes are as follows:

  • For SBC 1000: 1MiB
  • For SBC 2000: 4MiB
  • For SBC SWe Edge: 5MiB

Music files must be one of the following formats:

  • WAV
  • PCMA (not supported in SBC SWe Edge)
  • PCMU (not supported in SBC SWe Edge)
  • PCM (not supported in SBC SWe Edge)

For detailed information about uploading a Music on Hold file, see Uploading Music on Hold Files - SBC Edge Portfolio or Uploading Music on Hold Files - SBC SWe Edge.

FXS Port

A list of available FSX ports from which live audio may be sourced. The FXS Port field is only visible when Live is selected from the Music on Hold Service drop-down list.

Other Options - Field Definitions

Echo Canceller Type Option

This field applies to SBC 1000/2000 only.

Specifies the type of Line Echo Cancellation (standard or dual filter).

The standard LEC covers 128ms tail length (echo delay) and employs a 24ms sparse (non-zero coefficients) filter. The Dual Filter (background and foreground) Line Echo Canceller (LEC) covers 128ms tail length and uses 48ms sparse foreground filter. The Dual Filter is expected to perform better during double talk or slow echo-path change. Selection of the Dual Filter option may result in reduced channel densities.

Ribbon recommends not applying any change to the Echo Canceller Type Option unless the system is idle (no calls). Applying a change while the system is not idle may result in unknown behavior.


Echo Cancel NLP Option

This field applies to SBC 1000/2000 only.

Specifies the level of echo cancellation employed by the SBC Nonlinear Signal Processor.

The default value is Mild. However, there are two additional levels of echo cancellation: Strong and Aggressive. As each telephony system implementation varies, their echo characteristics similarly vary. Adjust the level of echo cancellation to suit your particular deployment. Too little cancellation may result in a persistent echo; too aggressive, and you may experience voice "clipping."

Send Stun Packets

This field applies to SBC 1000/2000 only.

Specifies whether STUN packets are generated from the SBC. The SBC sends STUN packets on the RTP and RTCP ports on all outbound IP call legs to open ports in the firewall (between the SBC and the Internet). The ability to turn this option on/off is for customers who do not have a firewall and would like a way to turn off STUN packet generation. Three options are available: Always (STUN packets are generated and sent by the SBC), Except Teams (To not initiate STUN packets towards MS Teams) or Disable (STUN packets are not generated). Default option: Always.