1. Sonny (Sechang) Son Computer Sciences Department University of Wisconsin-Madison sschang@cs.wisc.edu Dealing with Internet Connectivity in Distributed Computing

2. www.cs.wisc.edu/condor 2 Firewalls & Private Networks › Firewalls  cheap and good way to protect networks  headquarters of integrated security systems › Private networks  A solution to IPv4 address shortage problem  Easy network management & easy address planning › Connections are blocked!

3. www.cs.wisc.edu/condor 3 Connectivity Problem Central Manager Exec MachineSubmit Machine startd negotiation Job Xfer shadowschedstarter Ad match

4. www.cs.wisc.edu/condor 4 Connectivity Problem Central Manager Exec MachineSubmit Machine startd negotiation Job Xfer shadowschedstarter Ad match X X

5. www.cs.wisc.edu/condor 5 Connectivity Problem Central Manager Exec MachineSubmit Machine startd negotiation Job Xfer shadowschedstarter Ad match X X

6. www.cs.wisc.edu/condor 6 Connectivity Problem › Collaboration becomes difficult or impossible › Resources are wasted

7. www.cs.wisc.edu/condor 7 Agenda › Introduction › DPF (Dynamic Port Forwarding) › GCB (Generic Connection Brokering) › Future Work › Conclusion

8. www.cs.wisc.edu/condor 8 Dynamic Port Forwarding B DPF lib DPF agent A Client Server NAT X A  XA  B B = socket(); bind(B, ANY); getsockname(B, X ); BIND (B) X X  B X A = socket(); connect(A, X);

9. www.cs.wisc.edu/condor 9 DPF › Basic Idea: On-demand open/close › Supports Linux NAT box › Can support any firewall with APIs such that open, close, list › Fast & scalable

10. www.cs.wisc.edu/condor 10 GCB: socket registration BGCB lib Broker X Server AGCB lib Client B = socket(); bind(B, ANY); getsockname(B, X ) BIND (B) X X

11. www.cs.wisc.edu/condor 11 GCB: passive connection B GCB lib Broker X Server AGCB lib Client connect(A, X ) CONNECT (X) PASSIVE CONTACT (A)

12. www.cs.wisc.edu/condor 12 GCB: relay connection B GCB lib Broker X Server AGCB lib Client connect(A, X ) CONNECT (X) ACTIVE (X) CONTACT (Y) Y

13. www.cs.wisc.edu/condor 13 GCB › Basic Idea: reversing the direction underneath the application › Supporting Environments  No requirement to firewalls  Outbound connections are allowed › GCB requires no control on your firewall

14. www.cs.wisc.edu/condor 14 Future Works › Support for multiple connection mechanisms › Security › Dynamic open/close for outbound › eGCB (extended GCB)

15. www.cs.wisc.edu/condor 15 Connection Setup inagent outagent server client F/W 1) registration 2) open for outbound 3) negotiation 4) connection setup

16. www.cs.wisc.edu/condor 16 Conclusions › DPF is fast and scalable › GCB requires no control on headnodes › eGCB provides wide coverage › GCB and eGCB can be used by other applications

17. www.cs.wisc.edu/condor 17 Thank you! Sonny (Sechang) Son Rm# 3387 sschang@cs.wisc.edu