Circuit emulation services over ethernet-part 1: clock synchronization using timestamps

ABSTRACT

Due to Ethernet's ubiquity, simplicity, scalability and cost effectiveness there is significant customer demand for Ethernet-based access and transport in the metropolitan network. Many service providers have recognized this need and are currently establishing Ethernet-based services to meet this demand. The migration to all-Ethernet access will not be instantaneous since many customers currently have legacy TDM access interfaces on their routers and PBX equipment. Circuit Emulation Services (CES) over Ethernet provides TDM circuit emulation to support TDM traffic such as T1/E1, T3/E3, OC3/12, etc. This two-part paper presents the application of CES over Ethernet as well as a new technology that addresses the issues associated with clock recovery and synchronization in an Ethernet network with its inherent network jitter. Part 1 describes a clock synchronization technique where a transmitter periodically sends explicit time indications or timestamps to a receiver to enable the receiver to synchronize its local clock to the transmitter's clock.

REFERENCES

• 1: James Aweya, Trunking of TDM and narrowband services over IP Networks, International Journal of Network Management, v.13 n.1, p.33-60, January/February 2003 [doi>10.1002/nem.458]
• 2: 2. http://www.ietf.org/html.charters/pwe3- charters.html.
• 3: 3. http://www.metroethernetforum.org.
• 4: 4. http://www.ieee.org/groups/802/3/efm.
• 5: 5. Lau RC, Fleischer PE. Synchronous techniques for timing recovery in BISDN. IEEE Trans. Communications 1995;43(2/3/4):1810-1818.
• 6: 6. ATM Forum af-vtoa-0078.000. Circuit emulation service interoperability specification version 2.0. January 1997.
• 7: 7. Lindsey WC, Chie CM. A survey of digital phase-locked loops. Proc. IEEE, 1981;69(4):410-431.
• 8: 8. Best RE. Phase-locked loops. Design, simulation, and applications. Fourth Edition. 1999; McGraw-Hill.

INDEX TERMS

Primary Classification:
  C. Computer Systems Organization
  C.2 COMPUTER-COMMUNICATION NETWORKS
      C.2.5 Local and Wide-Area Networks
          Subjects: Ethernet (e.g., CSMA/CD)

Additional Classification:
  C. Computer Systems Organization
  C.2 COMPUTER-COMMUNICATION NETWORKS
      C.2.3 Network Operations
          Subjects: Network management
  C.4 PERFORMANCE OF SYSTEMS
      Subjects: Reliability, availability, and serviceability; Fault tolerance

General Terms:
Performance, Reliability, Verification