14. Quality of Service

14. Quality of Service

Although not the focus of this paper, Quality of Service is a key component of any VPN service. In MPLS/BGP VPNs, existing L3 QoS capabilities can be applied to labeled packets through the use of the "experimental" bits in the shim header [MPLS-ENCAPS], or, where ATM is used as the backbone, through the use of ATM QoS capabilities. The traffic engineering work discussed in [MPLS-RSVP] is also directly applicable to MPLS/BGP VPNs. Traffic engineering could even be used to establish label switched paths with particular QoS characteristics between particular pairs of sites, if that is desirable. Where an MPLS/BGP VPN spans multiple SPs, the architecture described in [PASTE] may be useful. An SP may apply either intserv (Integrated Services) or diffserv (Differentiated Services) capabilities to a particular VPN, as appropriate.