1. Method in a packet based communication network including network domains to establish a virtual leased line (VLL) between a source (SRC) and a destination (DST) in different domains in order to achieve packet transfer between the source and the destination, wherein a bandwidth broker (BB) is associated to each network domain, the method comprises the following steps:', 'i) generate a request from an entity for a Virtual Leased Line (VLL) having a predefined Quality of Service (QoS) from a source network (SRC) to a destination network (DST) and apply the request to a Bandwidth Broker of a domain A (BBA) associated to the source network;', 'ii) BBA establishes the different domains involved to reach the destination network (DST);', 'iÏx8b) BBA directly or indirectly passes requests to all Bandwidth Brokers of the involved domains regarding a VLL of the predefined QoS from ingress to egress of each domain;', 'iv) each involved bandwidth broker performs admission control in its domain;', 'v) each involved bandwidth broker returns a result of the admission control to BBA that passes it back to the requesting entity and if the request was admitted along all domains between SRC and DST a VLL of the predefined QoS is granted.

2. Method according to claim 1 , c h a r a c t e r i z e d i n that the method comprises the following step to be performed after step v): vi) BBA engages in Traffic Conditioners (TC) configuration in the ingress router for SRC in order to establish a VLL of the predefined QoS.

3. Method according to claim 1 , c h a r a c t e r i z e d i n that step iv) comprises the following sub-step: passing a request to one or many involved intra-domain brokers (IDB) in hop areas in the involved domains, wherein each intra-domain broker performs admission control.

4. Method according to claim 1, characterized in that in step iv) in addition to the admission control a Label- Switched Path (LSP) setup is performed.

5. Method according to claim 1, characterized in that said domains comprise at least one Differentiated Services (DiffServ) domain and one Multiprotocol Label Switching (MPLS) domain.

6. Method according to claim 5, characterized in that in a MPLS domain the BB is responsible for passing resource requests to the intra-domain brokers (IDB), wherein each intra-domain broker is responsible for admission control and LSP setup.

7. Method according to claim 1, characterized in that said predefined QoS is a rate R.

8. Method according to claim 1, characterized in that the bandwidth broker comprises a topology map and routing information to be able to perform path sensitive admission control of incoming requests, wherein the information is retrieved by peering as a link-state router.

9. Method according to claim 8, characterized in that the bandwidth broker comprises a data- structure which keeps resource usage information over time for each link in the topology which enables ability to plan ahead of time

10. Method according to claim 1, characterized in that a bandwidth broker in a specific domain performs admission control for all links in the path that belong to that domain

11. Method according to claim 1, characterized in that a bandwidth broker comprises a storage, where it stores records of all its granted requests and also user-related data such as policies or accounting information.']