Ethernet Bandwidth Considerations for MLC 8000s

The Ethernet link between MLC 8000 devices carries G.711 encoded voice. When calculating the bandwidth capacity for links between Hub sites and Base Radio sites, the G.711 traffic must be considered. To ensure optimal analog-only and mixed mode audio performance, each MLC 8000 talkpath vocoded with G.711 should be considered equivalent to three analog conventional talkpaths vocoded with G.728 (approximately three times the bandwidth).

A talk path is defined as a single audio stream. For example, the inbound audio stream from a receiver to a comparator comprises one talk path. The outbound audio stream from a comparator to a base radio comprises one talk path. A full duplex ‘repeater’ audio stream (from receiver to comparator to base station) is two talk paths.

MLC 8000 bandwidth considerations are as follows:

• For 20 ms audio frames, the packet load is 50 per second and the bandwidth utilization is 81.6 Kbps
• These figures should be multiplied by the number of base radios

Contact your Motorola Solutions representative for bandwidth planning tools and assistance.

Network equipment loading requirements

The MLC 8000 uses G.711 vocoding. When a G.711 channel is added onto a switch, the bandwidth between the Hub/base radio or IP Simulcast Prime/Subsite is adjusted accordingly.

• Router equipment at the Prime Site and at each subsite must provide for the following packet loading capacity: 50 packets per second, multiplied by the number of talk paths (inbound and outbound). As a general rule, the sum of packet loading at each of the Subsite routers is approximately equal to the loading requirement on the router at the Prime Site.
• Remember to budget for additional packet loading capacity due to traffic associated with non-audio operations (file transfer, SNMP, NTP packet activity).