Patent EP-1959637-A1 (EP)
Inventor: MENDES PAULO
IPC: H04W80/10
Filed: 2007-02-16
Abstract: A method for end-to-end session-aware connectivity control in heterogeneous networks being performed by network agents located at the edges of domains of heterogeneous networks, said method comprising: 
assigning a unique global session identifier along the end-to-end path to each multi-user session; 
publishing by said sender of unicast or multicast sessions information about the available sessions including the global session identifier and information about the session-flows and the source address to a network agent to which it is connected or to which it is moving to in order to enable subscription to said sessions by a receiver; 
whereas further network agents are provided along the session path, whereas said network agents comprise: 
an address allocation controller interface for enabling the request of the allocation of a local channel identifier to which a multi-user session flow is associated inside or between domains; 
said method further comprising: 
maintaining state about the multi-user sessions whereas said state includes per-session and per-flow state about the current sessions in a domain or between domains to which a network agent is associated; whereas; 
said network agents are distributed along said session path, and said method comprises: 
receiving by an ingress network agent one or more sessions from said source and publishing information about said sessions from said source and forwarding it downstream along further network agents towards receivers; 
sending from a receiver via an application protocol a subscribe message through an access agent towards said source indicating that the receiver wishes to subscribe the session and forwarding said message upstream towards said source along the network agents located in the session path; 
in each network agent where said request is received, verifying by querying said state information if the requested session is already received by said network agent, and if not, forwarding said subscribe message further upstream; 
if the session is found to be received by an network agent, stop forwarding upstream said subscribe message and verifying if the session is already active towards the receiver; 
if said verification is positive, forwarding said subscribe message downstream towards a network agent of a domain to which said access agent belongs; 
if said verification is negative, performing the following steps: 
a) requesting from the address allocation controller interface the allocation of a channel identifier for the downstream session flow and updating the outgoing interface table of said network agent with said channel identifier and the address of the next network agent towards the receiver; 
b) in the next network agent downstream towards the receiver, updating the incoming interface table with information about the session identifier and channel identifier, requesting the allocation of a channel identifier for the downstream session flow and updating the outgoing interface table said network agent with said channel identifier and the address of the next network agent towards the receiver; 
 
verifying whether the access agent has been reached, and if this is not the case, repeating said steps a) and b) above until said access agent is reached, 
if said access agent is reached, requesting from the address allocation controller interface the allocation of a channel identifier for the downstream session flow and updating the outgoing interface table of said network agent with said channel identifier and joining said session by said receiver through said access agent.