one through which it is sent) of the node which is the start point of the tunnel, and as the destination IP address the IP address of a network interface belonging to a network node that ends the tunnel (that is, drops the added IP header for tunneling purposes, decrypts the original packet, and processes it further). The primary use of IPsec in telecom operators' networks is for creation of secured VPNs, which are used to carry aggregated Internet traffic of a given type (e.g. VoIP, IPTV, traffic from business users, Internet traffic, signaling and control traffic). The VPNs can be used over the public Internet (e.g. for secure access to an office computer 6.5 QoS for Business Users (VPN Services) from any place) or over managed IP networks (this is typically used by telecom operators for carrying different types of traffic in different VPNs). In fact, it is very unlikely that an original IP packet created by the end-user host will be routed as such through the telecom operator's core and transport networks. Although in theory there are routing protocols which can route the packets by using source and/or destination addresses, in practice that is not enough to provide the required QoS. And the QoS is provided not only to traffic that originates and terminates over the managed IP networks (e.g. carrier-grade VoIP as PSTN/ISDN replacement, IPTV, VPN for business users as leased-lines replacement), it is also needed for aggregated IP traffic that originates and terminates in the public Internet network. So, VPN solutions are used in telecom operators' IP transport networks. For QoS pro- vision of VPNs (e.g. to provide sustainable or constant bitrate for the VPN end-to-end) there is the possibility to use various approaches for QoS provision, such as Integrated Services (IntServ), Differentiated Services (DiffServ), as well as MPLS [19]. However, the QoS in transport IP networks from the beginning of this century is mainly provided with MPLS or MPLS/Border Gateway Protocol (BGP) IP VPNs [20]. MPLS is used for QoS pr