 provider needs to provide adequate ser- vice bandwidth between any pair of VPN endpoints (e.g. routers, switches), along the path of that VPN, which is referred to as a "pipe." In this model, if the customer for VPN services wants to reach N destinations, then QoS requirements should be spec- ified for N paths (i.e. N pipes). The pipes can be established in the network by using MPLS (e.g. though label switched paths). The QoS requirements for pipes provide isolation between the QoS metrics of each pipe. VPN hose model. In this case are specified QoS requirements per VPN endpoint and not for each pair of VPN endpoints. This model is targeted for multi-point to multi-point VPN services. In such case, unlike targeting the SLA on point-to-point basis, i.e. for VPN pipe basis, the SLA is defined in terms of "hose" between each site (on customer side) and the provider-edge (on VPN provider network side). Each such "hose" is defined with two KPIs: Ingress committed bitrate. The agreed VPN hose bitrate from the customer toward the provider network. Egress committed bitrate. The agreed VPN hose bitrate from the provider toward the customer. For example, VPN pipes are replacement (in IP transport networks environments) of leased lines (in circuit switching transport networks). Typical implementation of VPN is any-to-any connectivity using IP or MPLS technology based on the Border Gateway Protocol (BGP)/MPLS VPNs [11]. Overall, the main QoS parameters (i.e. KPIs) for VPN services include the following: Packet delay, jitter, and packet loss. These are not specific VPN QoS metrics, but refer to all IP-based services. However, their importance is related to the type of traffic carried in the VPN. So, these KPI reflects in fact the KPIs for the service type carried within the VPN (voice, IPTV streams, Internet data, etc.). 7.5 KPIs for Data Services and VPNs site 1 site 2 Pipe 1-2 Pipe 1-4 Pipe 2-4 Pipe 1-3 Service provider IP/MPLS network site 3 (VPN pipe) site 4 site 1 site 2 Service provider IP/MPLS network (VPN hose) site 