Network Requirements

The Scout Console requires an IP network to interconnect all of the elements, from the consoles, to the VPGate gateway, to Outposts, and to the endpoints. The minimum requirement is a 100 Mbps switched Ethernet network that is compatible with, and configured to recognize, DiffServ Code Point (DSCP) tagged packets. DiffServe tags ensure the proper Quality of Service (QoS) for the VoIP packets. All LAN segments must support multicast.

Each Scout console requires a minimum of either one or two Ethernet connections. If using the Hardware Media Workstation, two Ethernet connections are required, one for the console PC and one for the media workstation. If using the Software Media Workstation, only one for the console PC is required. More are required when implementing redundant networks. Each VPGate requires one Ethernet port.

Outpost requires only one Ethernet port even though it supports two audio connections.

For more information on the topics presented in this section, see the VPGate Network Architecture and Networking Design Considerations document.

Jitter and Latency

The main contributors to latency are the sum of the network transit time and the jitter buffer size. For both Outpost and the Scout media workstations (hardware media workstation and software media workstation), the jitter buffer can be configured on a per device basis. Scout supports variable packet sizes down to 20 milliseconds (ms), which allows the buffer to be set at 60 ms. Generally, a goal of less than 150 ms end-to-end latency is preferred.

Scout allows for jitter ranging from 60 ms to 2.5 seconds.

Bandwidth

Outpost requires only one Ethernet port even though it supports two audio connections.

Sufficient bandwidth must be available on the IP network. A typical Outpost-to-VPGate IP connection for one simplex radio can consume 24 kbps to 80 kbps for audio transmission during activity, depending on codec choice. A fully populated repeater network can require more than 700 kbps during normal activity.

For Voice Over Internet Protocol (VoIP) recording (IP recording), Scout can handle all audio from the Scout Console which includes Select and Unselect audio, plus all endpoint audio (Outpost endpoints and all others). The audio packets sent to the recorder are standard RTP packets. When using IP recording, verify that the network includes enough bandwidth to support IP recording. The required bandwidth can vary from 30 kbps to 85 kbps, depending upon the audio codec in use.

QoS (Quality of Service)

Avtec’s minimum requirements are 100 Mbps switched Ethernet and that is compatible with, and configured to recognize, DSCP tagged packets to ensure the proper Quality of Service. LAN segments must support multicast.

Addresses and Ports

For efficiency on the LAN, VPGate uses multicast to forward the unicast packets from Outpost and other endpoints to the Scout consoles. Whenever an endpoint is active and transmitting its audio to VPGate, the audio is automatically forwarded to one or more consoles that have the endpoint selected or monitored.