OSPF for Broadband Wireless Campus Backbone Joseph Hui ISS Chair Professor and Director, Telecommunications Research Center Arizona State University

Talk Outline Applications for Wireless Broadband Campus Networks Optical versus Radio Frequency OSPF for Broadband Wireless Networks On-going embedded system prototype.

Applications of Broadband Wireless Backbone Large data storage facilities scattered on campus Growing need for multimedia educational material storage/retrieval Digital/video libraries Massive data stores (Mars Probe, 3D models) Wireless LAN hot spots Portable wireless multimedia booths?

ASU Campus Backbone Hub and Spoke Gigabit Ethernet. Three level hierarchical network East-Central-West Campus A few isolated, off-campus buildings Want: Scalable and reconfigurable networks Solutions: –Wireless broadband –Distributed Storage Area Networks –Reliable OSPF protocol for wireless links

Proposed Broadband Wireless Network Topology An adjunct broadband wireless network Mesh/Ring network for the second tier hubs Mesh/relay network for third tier nodes

Optical versus Radio Networks Advantages of optics: –No spectrum licensing –No multipath problems –Cheaper/smaller transceivers –high speed/DWDM –Excellent channel isolation –Security Advantages of radio: –LOS not mandatory –Longer distances –More weather resistant –Less background noise –Ease of pointing –Eye safe

Going Optical

Wireless Campus Network Current approaches –LMDS for WLL, not backbone –Hub architecture –Shared bandwidth –LEC model –DSL over ATM Proposed Approach: –Totally wireless backbone, no distinguishable local loops. –Mesh architecture –Multiple parallel paths –Internet model –{SCSI,FC,10 x BaseT,TCP,IB} over IP

Key Challenges Optical links – propagation, pointing, power budget, eye safety Data links –link/node failure, traffic measurements, QoS control Network routing/management –Ad-hoc routing, IP switching, resource discovery, traffic balancing, domain management System Analysis –Interface interoperability, multiple protocols, device mapping/configurations.

Network Types Meshed Networks –Fully Meshed (Each and every node is connected to all others by no more than one hop) –Partially Meshed (A node may be connected to other nodes by more than one hop) Fragile Networks –Any link of the network may become inoperative at any time. The failure of a single link should not prohibit message delivery

The Effect of Fragility (Providing A High Availability Environment) 1. Router Failure 2. CPE Failure 3. Premise Link Failure 4. Link Failure

Protocols for Wireless Optical Ad-Hoc Networks 1. Link-state monitoring 2. QoS provisioning 3. Rapid yet distributed rerouting upon link/node failure 4. Resource discovery and management 5. Multi-protocol adaptations

Reliable IP based on OSPF OSPF is the predominant IP protocol for – Intra-domain, distributed, link-state based routing – Problem: rerouting require broadcast of link-state To make OSPF reliable – QoS control based on DiffServ, TOS queue scheduling – Pre-compute multiple paths based on QoS and link failure – Rapid switch over to source routing if link or node fails Problem: Is it possible to retain much of OSPF distributed computation, yet able to route correctly when link/node fails?

Reliable IP based on OSPF Answer is Yes! Multipath OSPF with IP-encapsulation for source routing Node broadcasts link state infrequently – Each node compute multiple paths contingent on fault/QoS – Multiple IP for QoS assignments –Use of IP encapsulation to forward packets along precomputed path.

Experimental Prototypes The Existing Project –Pizza box Router for Network Edge use based on IP –Free Space Laser Link at 850 nm and 1Gb/s –Millimeter Wave RF Link at GHz and 1 Gb/s Applied both indoor and outdoor

Conclusion Distributed Router Development –Protocol (Reliable IP) –QoS Routing and QoS Link Management –Network Management (IP encapsulation) –Mirroring and Multicasting Four link implementations at 1 GHz –Free Space Laser –Wireless Millimeter Wave –Fiber optic –Copper Currently soliciting public and private funding for prototype