IP over ATM

1
IP over ATM

• IP over everything, ..., PoS, PoATM, Ethernet,
• IP will be transported over whatever L1/L2
  technology is best suited
• ATM will be a player in the Internet arena, but
  will not dominate
• Complexity
• OC-48c SAR non-existent, while OC-48c PoS
  interfaces exist
• Efficiency
• cell tax, duplication of functions
• Scalability
• VP/VC space, payload size doesnt scale with
  link speed
• ATMs prime qualities
• Virtual connectivity VPNs, multi-CoS networks
• Installed base, QoS?
• Co-existence with other, non-IP services

2
IP over SONET

• Higher utilization compared to IP/ATM (Sprint IP
  network)
• Problems with SONET framing
• TDM, designed mainly for voice service, not
  transparent to IP packets
• Scrambling
• Designers of new link technology are catering to
  the specific requirements of IP
• Basic functions of SONET are still needed
• Synchronization
• performance monitoring
• protection switching
• Path protection switching at L3 ?

3
IP over WDM

• The capacity of a DWDM fiber is already beyond
  160 Gbps, may well exceed 1 Tbps
• Transmission systems
• Virtual connectivity
• Role in Metropolitan Area Networks
• Optical packet/burst WDM networks
• Natural move ?
• To circumvent potential bottleneck of electronic
  processing
• Challenges
• Synchronization, burst mode receiver, replace
  SONET functionality
• Provide QoS due to lack of optical RAM
• Optical WDM layer protection/restoration may
  still needed
• Coarse, fast restoration