Differences

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

--- mywiki:gpon [2016/06/20 10:06] – 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
@@ Line 133: / Line 146: @@
 | AN | Access Network |
 | BE | Best-offer Bandwidth |
+| BWmap | bandwidth map |
 | CBU | Cell Base Unit |
 | DBA | Dynamically Bandwidth Assignment/Allocation |
@@ Line 161: / Line 175: @@
 | OCMI | ONU Management and Control Interface. |
 | 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 |
@@ Line 176: / Line 190: @@
 | RTD | Round Trip Delay |
 | RTT | Round Trip Time |
+| SerDes | Serializer/Deserializer pronounced sir-deez |
 | SFU | Single Family Unit |
 | SBU | Single Business Unit |