If wireless network and Voice over IP is already entrenched in the enterprise, the desire to combine them into a wireless local area network for voice will not be slow in coming. Laboratory LANline ready to share the experience of combining these technologies. Voice over IP and wireless LANs - the two technologies in recent years, going through the stage of rapid development. Both are perceived in the corporate area as a very demanding: the security aspects of data traffic and the level of voice quality in real time must be considered in the context of the limited capacity of common Radiostandards IEEE 802.11b and 802.11g standards within individual radioyacheek. With the success of the organization of the session protocol (Session Initiation Protocol, SIP) for VoIP in combination with the protocol of data transmission in real time (Real-Time Transport Protocol, RTP) in the telephone system, it becomes possible to combine the same components are fundamentally different manufacturers. VoIP business phone systems Configure my wireless network The wireless network laboratories LANline role of VoIP terminal equipment was placed on two phones Wi-Fi consumer class of UT-Starcom F1000 and ZyXEL P2000W v2 and PDA T-Mobile MDA Pro with support for GSM / WLAN running Windows Mobile 5 (identical to Qtek 9000, eRlus PDA IV and Vodafone VPA IV UMTS) (see Table 1). What unites them is that, in accordance with the 802.11b standard, they are able to exchange data at speeds up to 11 Mbps.
Only recently, the market began to appear phones Wi-Fi, working, like all laptops, according to the standard 802.11g with maximum data transfer rate 54 Mbps, thus ensuring more efficient use of bandwidth in a wireless network. UTStarcom, for example, presented at CeBIT flip phone F3000, corresponding to the standard 802.11g.
All three devices carry - if necessary - at least the minimum encryption, WEP (64/128 bit) for data transmission, which, however, no longer meets the recommended standards of encryption for wireless networks. UTStacom and MDA Pro additionally offer WPA with pre-issued keys (Pre-Shared Key, PSK). Windows Mobile 5 from Microsoft in addition to WPA allows for MDA Pro individual user authentication in accordance with standard 802.1H/EAR server RADIUS. The protocol-level security applications, as provided in the protocols of VoIP SIPS (RFC2246) and SRTP (RFC3711), for Wi-Fi phone is currently unavailable.
If Wi-Fi phones do not correspond to the level of security, which in accordance with the policy must have a corporate wireless network, voice traffic is transmitted on the network, should be separated from the rest of traffic. Parallel operation of independent radioyacheek is not always possible, so traffic should be separated within each radioyacheyki. This can be achieved for example by organizing radioyacheyke two logical wireless networks, each with its own SSID, as well as through the appropriate security settings: WEP and WPA encryption for VoIP with 802.1H/EAR or 802.11i for the mobile Internet jobs (Multiple SSID “).
Logical wireless VoIP with a low level of security not only offers little protection for the transmission of voice data, but also opens up, without taking additional measures, less secure access to corporate networks. The solution lies in its segmentation of virtual networks in accordance with standard IEEE 801.1q. Through this separation of compounds of VoIP-WLAN can be constructed, for example, only with the telecommunications systems: VoIP. In the laboratory LANline managed to implement this configuration using an access point Lancom 3550 and Managed Switch D-Link DES 3526.
Converged wireless network and Voice over IP
