Differences

This shows you the differences between two versions of the page.

--- mywiki:gpon [2016/06/20 10:03] – shaoguoh
+++ mywiki:gpon [2019/09/15 18:55] (current) – external edit 127.0.0.1
@@ Line 15: / Line 15: @@
 ====== GEM Format ======
 {{:mywiki:gem.png|}}
+There are 2 types of GEM Channels:
+    Downstream-only GEM Channels - These channels are used to transmit downstream broadcast/multicast traffic from OLT to all ONTs. The ONTs identify traffic meant for them based on GEM Port ID.
+    Bi-directional GEM Channels - These channels are used for upstream and downstream traffic between the OLT and the ONT. The frames are transmitted from the OLT into the GPON interface and are forwarded only on the U interface of the ONT on which that GEM Port has been assigned.
 PTI Type
@@ Line 36: / Line 42: @@
 A traffic bearing object within an ONT that represents a group of logical connections, and is treated as a single entity for the purpose of upstream bandwidth assignment on the PON. In the upstream direction, it is used to bear the service traffic. Each T-CONT corresponds to service traffic of one bandwidth type. Each bandwidth type has its own QoS feature.
-ALLOC_ID:
+**ALLOC_ID**:
 Each T-CONT is identified by the ALLOC_ID uniquely. The ALLOC_ID ranges from 0 to 4095. It is allocated by OLT i.e. a T-CONT, and can only be used by one ONT per PON interface on the OLT.
@@ Line 44: / Line 50: @@
 A GPON Encapsulation Method (GEM) port is a virtual port for performing GEM encapsulation for transmitting frames between the OLT and the ONT. Each different traffic-class (TC) per UNI is assigned a different GEM Port. Each T-CONT consists of one or more GEM Ports. Each GEM port bears one kind of service traffic i.e. a T-CONT type.
-GEM Port ID:
+**GEM Port ID**:
 Each GEM Port is identified by a port ID uniquely. The Port ID ranges from 0 to 4095. It is allocated by the OLT, i.e. a GEM port, and can only be used by a single ONT per PON interface on the OLT.
@@ Line 66: / Line 72: @@
 {{:mywiki:upstream-framing-structure1-1024x496.jpg|}}
+{{:mywiki:gpon_up_traffic.png|}}
 ====== Downstream Frame structure ======
@@ Line 124: / Line 132: @@
     S-start，S-stop：start and stop times (16bits fields, in Bytes from beginning of US frame)
     CRC：CRC(cyclic redundancy check) Checksum.
+{{:mywiki:pon_down_traffic.png|}}
+====== VLANs and GEM Ports ======
+https://sites.google.com/site/amitsciscozone/home/gpon/gpon-vlans-and-gem-ports
 ====== Terminology ======
 | AB | Assured Bandwidth |
-| AES |  Advanced Encrypt System |
+| AES | Advanced Encrypt System |
-| AGC |  Automatic Gain Control |
+| AGC | Automatic Gain Control |
 | AN | Access Network |
 | BE | Best-offer Bandwidth |
-| CBU |  Cell Base Unit |
+| BWmap | bandwidth map |
-| DBA |  Dynamically Bandwidth Assignment/Allocation |
+| CBU | Cell Base Unit |
+| DBA | Dynamically Bandwidth Assignment/Allocation |
 | DSLAM | Digital Subscribe Line Access Multiplexer |
 | EFMA | Ethernet in the First Mile Alliance |
 | EPON | Ethernet Passive Optical Network |
-| EqD |  Equalization Delay |
+| EqD | Equalization Delay |
-| FB |  Fixed Bandwidth |
+| FB | Fixed Bandwidth |
-| FSAN |  Full Service Access Networks |
+| FSAN | Full Service Access Networks |
-| FTTB |  Fiber to the Building |
+| FTTB | Fiber to the Building |
-| FTTC |  Fiber to the Curb |
+| FTTC | Fiber to the Curb |
-| FTTH |  Fiber to the Home |
+| FTTH | Fiber to the Home |
 | FTTN | Fiber to the Network |
 | GEM | GPON Encapsulation Method |
-| CID |  Consecutive Identical Digit |
+| CID | Consecutive Identical Digit |
-| GPON |  Gigabit-Capable Passive Optical Network |
+| GPON | Gigabit-Capable Passive Optical Network |
 | GTC | transmission convergence |
 | HEC | header error check |
-| JF |  Jumbo Frames |
+| JF | Jumbo Frames |
-| MSAN |  Multi-service Access Network |
+| MSAN | Multi-service Access Network |
-| MDU（Multi Dwelling Unit） |
+| MDU | Multi Dwelling Unit |
-| MTU（Multi Tenant Unit） |
+| MTU | Multi Tenant Unit） |
-| NAB |  Not-assured Bandwidth |
+| NAB | Not-assured Bandwidth |
 | NE | Network Element |
 | NNI | network-to-network interface | An NNI circuit can be used for interconnection of signalling (e.g., SS7), Internet Protocol (IP) (e.g., MPLS) or ATM networks. |
-| NRZ |  Non-return-to-Zero |
+| NRZ | Non-return-to-Zero |
-| OAM |  Operation, Administration and Maintenance |
+| OAM | Operation, Administration and Maintenance |
-| OCMI |  ONU Management and Control Interface. |
+| OCMI | ONU Management and Control Interface. |
-| ODN （ Optical Distribution Network） |
+| ODN | Optical Distribution Network |
-| OLT （ Optical Line Terminal） |
+| OLT | Optical Line Terminal |
 | OMCI | The ONU management and control interface |
 | ONT | Optical Network Terminal | Almost same with ONU but normally with large port count, like E1/GE |
 | ONU | Optical Network Unit |
-| P2P |  Point to Point |
+| P2P | Point to Point |
-| P2MP |  Point to Multi-Point |
+| P2MP | Point to Multi-Point |
-| PCBD |  Physical Control Block Downstream |
+| PCBD | Physical Control Block Downstream |
 | PLI | Payload Length Indicator |
 | PLOAM | Physical layer OAM Operations, Administrations and Maintenance |
-| PON |  Passive Optical Network |
+| PON | Passive Optical Network |
-| POS |  Passive OpticalSplitter |
+| POS | Passive OpticalSplitter |
 | Port-ID | traffic identifier | Identifies the target ONU |
 | PTI | payload type indicator |
-| RTD |  Round Trip Delay |
+| RTD | Round Trip Delay |
-| RTT |  Round Trip Time |
+| RTT | Round Trip Time |
-| SFU |  Single Family Unit |
+| SerDes | Serializer/Deserializer pronounced sir-deez |
-| SBU |  Single Business Unit |
+| SFU | Single Family Unit |
-| SNI |  Service Node Interface |
+| SBU | Single Business Unit |
-| TDM |  Time Division Multiplexing |
+| SNI | Service Node Interface |
-| TDMA |  Time Division Multiple Access |
+| TDM | Time Division Multiplexing |
-| T-CONT |  Transmission Containers |
+| TDMA | Time Division Multiple Access |
+| T-CONT | Transmission Containers |
 | UNI | User Network Interface | a demarcation point between the responsibility of the service provider and the responsibility of the subscriber. |
-| VoD |  Video On Demand |
+| VoD | Video On Demand |
 | WDM | Wavelength Division Multiplex Module |