1. MPCP (Multipoint Control protocol)
Professor : Ho-Ting Wu
Speaker : 簡睿毅

2. Outline
Overview EPON
MPCP
Summary

3. Outline
Overview EPON
MPCP
Summary

4. PON (Passive Optical Network )
Features of a passive optical network:
an attractive solution to implement FTTB (fiber to the build) and FTTH (fiber to the home)access networks FTTH deployment scenarios
a point-to-multipoint optical network
only passive optical components:
Couplers and Splitters
two primary types of PON technologies:
ATM PON (APON)
Ethernet PON (EPON)

5. FTTH deployment scenarios

6. Architecture of PONs OLT: Optical Line Terminal
ONU: Optical Network Unit

7. Ethernet PON
EPON started to be standardized by IEEE 802.3ah EFM since 2001
Ethernet is a ubiquitous technology: deployed widely in LAN, MAN and WAN
Ethernet is more attractive to PON than ATM
high speed: up to 10 Gigabit/s
lower cost of Ethernet equipments than those of ATM
easier interoperability than that in ATM
lower overhead

8. Features of Ethernet PON
All data packets carried in EPON are encapsulated in Ethernet frames
Broadcasting in the downstream direction from the OLT to ONUs
Sharing the upstream channel capacity among ONUs
Collision will occur when different ONUs transmit data simultaneously
Method is needed for multiple access — Medium Access Control (MAC) protocols

9. Downstream traffic in EPON

10. Upstream traffic in EPON

11. Outline
Overview EPON
MPCP
Summary

12. MPCP (Multipoint Control protocol)
Introduction
Two mode of operation
Discovery Protocol
RTT (Round-trip time) measurement
Messages Format
Messages Operation
MPCP-Goals

13. MPCP (Multipoint Control protocol)
Introduction
Two mode of operation
Discovery Protocol
RTT (Round-trip time) measurement
Messages Format
Messages Operation
MPCP-Goals

14. Basic Characteristics
The Multi-Point Control Protocol (MPCP) specifies a control mechanism between a Master unit and Slaves units connected to a Point-to-Multi-Point (P2MP) segment to allow efficient transmission of data
MPCP is implemented in MAC Control layer
MPCP uses five MAC Control messages
- GATE, REPORT, REGISTER_REQ,REGISTER,REGISTER_ACK

15. MPCP (Multipoint Control protocol)
Introduction
Two mode of operation
Discovery Protocol
RTT (Round-trip time) measurement
Messages Format
Messages Operation
MPCP-Goals

16. Two mode of operation
Auto Discovery mode
- to detect newly connected ONUs and learn the round-trip
delay and MAC address of that ONU
Normal mode
- to assign transmission opportunities to all initialized ONUs

17. Auto Discovery mode (1/2)
OLT allocates an initialization slot, an interval of time when no previously initialized ONUs are allowed to transmit
OLT sends an initialization GATE message advertising the start time of the initialization slot and its length
Only un-initialized ONUs will respond to the initialization GATE message

18. Auto Discovery mode (2/2)
When the local clock located in the ONU reaches the start time of the initialization slot
,the ONU will transmit its own message (initialization REPORT)
When the OLT receives the REPORT from an un-initialized ONU, it learns its MAC address and round-trip time

19. MPCP (Multipoint Control protocol)
Introduction
Two mode of operation
Discovery Protocol
RTT (Round-trip time) measurement
Messages Format
Messages Operation
MPCP-Goals

20. Discovery Protocol
Four MAC control messages
– Discovery GATE: Creates transmission opportunity for undiscovered devices
– Register_Request: ONU response to “Discovery Gate”
– Register: OLT response to Register_Request
– Register_Ack: ONU response to Register
ONUs can wake-up Simultaneously
– Protocol must deal with contention in Register_Requests
Multiple ONUs can potentially be registered within single Discovery time period

21. Auto Discovery

22. ONU Behavior During Discovery
At Power-up / Reset, an ONU enters Discovery State:
– Undiscovered ONUs Await Reception of “Discovery Gate”
message from OLT
Unregistered ONU responds only:
– If received message’s Logical Link ID(LLID) matches
discovery/default LLID and the grant type is discovery

23. OLT Behavior During Discovery
OLT Must Periodically Reserve Time Periods for Discovery
–The Frequency of discovery windows can be chosen for
desired overhead
Since Undiscovered ONU Addresses are Unknown
– “Discovery Gates” are broadcast to all ONUs

24. Failure Modes OLT assumes ONU is unregistered if:
– REGISTER_ACK message wasn’t received at the first grant
opportunity
– ONU responds to “Discovery GATE” messages
ONU assumes it is unregistered if:
– After sending a REGISTER_REQUEST message, it receives
a “Discovery GATE” before receiving a REGISTER message
– After sending a REGISTER_ACK message, it receives a
“Discovery GATE” before receiving a “Normal GATE” message

25. Resolving Discovery Contention
Some sort of randomization must be applied to ONU Register messages to minimize collisions

26. MPCP (Multipoint Control protocol)
Introduction
Two mode of operation
Discovery Protocol
RTT (Round-trip time) measurement
Messages Format
Messages Operation
MPCP-Goals

27. RTT measurement

28. MPCP (Multipoint Control protocol)
Introduction
Two mode of operation
Discovery Protocol
RTT (Round-trip time) measurement
Messages Format
Messages Operation
MPCP-Goals

29. Messages Format OLTONU GATE , REGISTER ONUOLT
REPORT , REGISTER_REQUEST , REGISTER_ACK
Used only during discovery process
REGISTER , REGISTER_REQUEST , REGISTER_ACK

30. GATE/REPORT Behavior Protocol layer conveys information
- OLTONU bandwidth assignment
- ONU OLT bandwidth request
Service layer sitting above makes decisions
- OLT bandwidth allocation
- ONU bandwidth utilization
OLT sends GATE messages to ONU and guarantees no overlaps

31. MPCP (Multipoint Control protocol)
Introduction
Two mode of operation
Discovery Protocol
RTT (Round-trip time) measurement
Messages Format
Messages Operation
MPCP-Goals

32. GATE Operation(1/2)

33. GATE Operation(2/2)
ONU transmits only during the time indicated in the GATE
ONU MAC-control enables PHY transmission at the start of a GATE duration and disables it at the end of the GATE duration
GATE messages can be used with timestamps only

35. REPORT Operation(1/3)

36. REPORT Operation(2/3) REPORTs are generated in ONU MAC control client
- Indicate local conditions to OLT
REPORTs pass through the MAC-control
REPORTs are optional

37. REPORT Operation(3/3) A REPORT message may contain queue reports
The OLT must process REPORT messages
The OLT may consider the REPORT when allocating bandwidth
The ONU must issue REPORTs periodically
REPORT messages can be used with timestamps only

39. MPCP (Multipoint Control protocol)
Introduction
Two mode of operation
Discovery Protocol
RTT (Round-trip time) measurement
Messages Format
Messages Operation
MPCP-Goals

40. MPCP- Goals Optimize Network Resources
Address Service Provider Requirements

41. Outline
Overview EPON
MPCP
Summary

42. Point-to-Point Emulation (PtPE)

43. Shared-Medium Emulation (SME)

44. Combined PtPE and SME Mode

45. Summary
MPCP is compliant with deployed Ethernet by using P2P Emulation layer
An 802.3ah point-to-multipoint network is a layer
2 domain with a Bridge at the OLT having a direct
link to each ONU
Traditional Ethernet framing is maintained Peer-to-peer communications can be disabled at
bridge
MPCP is confined to one sub-layer – MAC Control
MPCP allows higher layer to implement various
DBA algorithms

46. Reference Ethernet Passive Optical Network (EPON)
Glen Kramer, University of California, Davis
Biswanath Mukherjee, University of California, Davis
Ariel Maislos, Passave Networks, Israel
Supporting differentiated classes of service in Ethernet passive optical networks
Glen Kramer and Biswanath Mukherjee , University of California, Davis
Sudhir Dixit and Yinghua Ye , Center, 5 Wayside Road, Burlington
Ryan Hirth , Communications, 755 Baywood Drive, Petaluma