1. 1 The Design and Implementation of Mobile Session Controller

2. 2 Session Controller Network Mobility SIP & SIP Mobility NAT Traversal Our Enhancement on Session Controller to Support Mobility Future Work

3. 3 Session Controller Border Firewall NAT http://www.sessioncontrollerforum.org/

4. 4 Network Mobility http://www.ietf.org/html.charters/nemo- charter.html Managing the mobility of an entire network The mobile network includes one or more mobile routers (MRs) which connect it to the global Internet. –It could be multi-homed. –None of the nodes behind the MR will be aware of the network's mobility, thus the network's movement needs to be completely transparent to the nodes inside the mobile network.

5. 5 Network Mobility (2) A basic approach for network mobility support is for each Mobile Router to have a Home Agent, and use bidirectional tunneling between the MR and HA to preserve session continuity while the MR moves. The MR will acquire a Care-of-address from its attachment point much like what is done for Mobile Nodes using Mobile IP. In this paper, we propose to handle SIP-based sessions with SIP mobility instead of Mobile IP, which is a better choice for VoIP, because it removes the “triangular routing”.

6. 6 SIP & SIP Mobility Shiang-Ming will provide the viewgraph of pre-call mobility & mid-call mobility However, this seems to be redundant with the call flows below. Probably we only need to briefly introduce SIP in this section.

7. 7 AP WiMAX WiFi

8. 8 The MSC Architecture

9. 9 NAT Traversal on Session Controller Registration Call Setup –Call Origination –Call Termination

10. 10 NATSIP ALG mapping table NAT Traversal for SC

11. 11 Registration Session ControllerUASIP Registrar REGISTER Contact: sip:ua@private_ip:5060 REGISTER Contact: sip:ua@public_ip:12348 Allocate a port for UA 200 OK

12. 12 Call Origination Allocate public ports for UA. –The design of Mobile Session Controller should adopt a port-restricted cone NAT.

13. 13 Call Origination Session ControllerUA UA2 INVITE + SDP1 Reserve two contiguous ports for a media stream INVITE + SDP1’ 200 OK + SDP2 Add RTP ports to the ACL 200 OK + SDP2

14. 14 Call Termination Similar. Just draw another figure.

15. 15 Enhanced Session Controller to Support Mobility Pre-call Mobility Mid-Call Mobility

16. 16 Pre-Call Mobility Session ControllerUA SIP Registrar SC detects IP address change and update the mapping table 200 OK REGISTER Contact: sip:ua@new_ip:12348

17. 17 Mid-Call Mobility Session ControllerUA UA2 INVITE (new Contact and Via) + SDP1” (new c=) 200 OK + SDP2 SC detects IP address change and update the mapping table RTP ACK

18. 18 Future Work