LAN telephony

Inconjunction withInternet telephony, LAN telephony based on VoIP is also becoming increasingly important. In principle, with LAN telephony the telephones are connected directly to the LAN and are switched via the IP communications server or the IP gateway.

Depending on the voice quality, a 10 Mbit/s Ethernet can transmit up to 100 voice connections with medium quality(G.723) in parallel with the data traffic if 10% of the available bandwidth is utilized. Since voice quality depends on the bandwidth provided and the delay times, the use of high-speed networks such as Fast Ethernet, Gigabit Ethernet or ATM is very beneficial to LAN telephony. To keep runtimes within the LAN low, the switches in the Ethernet should enable prioritization of data streams and also operate according to the cut-through method, since the frequently used store-and-forward method is rather unsuitable due to non-calculable delays.