14 files changed, 430 insertions, 157 deletions

diff --git a/_config.yml b/_config.yml
index 18317ca..b4a609d 100644
--- a/_config.yml
+++ b/_config.yml
@@ -124,7 +124,7 @@ just_the_docs:
       name: Tools
       nav_fold: true
     gpon:
-      name: GPON
+      name: GPON Resources
       nav_fold: true
     sfp_cage:
       name: SFP cage
diff --git a/_gpon/g_984_series.md b/_gpon/g_984_series.md
new file mode 100644
index 0000000..6887d7b
--- /dev/null
+++ b/_gpon/g_984_series.md
@@ -0,0 +1,289 @@
+---
+title: GPON G.984 Series
+has_children: false
+nav_order: 3
+layout: default
+---
+
+The information on this page is taken from the GPON standard and information from the major vendors of GPON equipment, each individual item containing a verifiable citation in the standard. Feel free to cite this page as: `{{ page.title }}, Hack GPON. Available at: https://hack-gpon.github.io{{ page.url }}`.
+
+| G.984.1                 | G.984.2                             | G.984.3                        | G.984.4                            | G.988 (ex G.Imp984.4)    |
+| ----------------------- | ----------------------------------- | ------------------------------ | ---------------------------------- | ------------------------ |
+| General Characteristics | Physical Media Dependant Layer      | Transmission Convergence Layer | ONT Management & Control Interface | OMCI Implementer's Guide |
+| Architecture            | Bit Rate/coding                     | GTC Protocol                   | Reference model                    |                          |
+| Distance/Reach          | Wavelength                          | GTC Framing                    | OMCI requirement                   |                          |
+| Split Ratio             | Optical element specs and operation | ONU Activation                 | MIBs                               |                          |
+| Protection              | Link budget (amendment)             | Security / FEC                 | OMCC                               |                          |
+|                         |                                     | Alarms / Monitoring            |                                    |                          |
+|                         |                                     | OMCI                           |                                    |                          |
+
+# General Concepts[^zyxel]
+
+- Bit Rate: 1.2 Gbps Upstream; 2.4 Gbps Downstream.
+- Physical Reach: Max physical distance between OLT and ONT.
+- Differential Fiber Distance: Distance between closest and farthest ONT from OLT (max = 20km)
+
+## Basic Performance Parameters[^cisco]
+
+| Upstream (Rate - Gbps) | Downstream (Rate - Gbps) |
+| ---------------------- | ------------------------ |
+| 0.15552                | 1.24416                  |
+| 0.62208                | 1.24416                  |
+| 1.24416                | 1.24416                  |
+| 0.15552                | 2.48832                  |
+| 0.62208                | 2.48832                  |
+| **1.24416**            | **2.48832**              |
+| 2.48832                | 2.48832                  |
+
+1.24416 Gbps up, 2.48832 Gbps down is the mainstream speed combination supported at current time.
+
+# GPON Terminology
+
+{% include image.html file="quick-start\gpon-terminology.png" alt="Overview of GPON Terminology" caption="Overview of GPON Terminology" %}
+
+## ONU Identifier (ONU-ID)[^zyxel]
+* 8 bit identifier (0~255)
+    * 0 .. 253 Assignable
+    * 254 Reserved
+    * 255 Broadcast/unassigned
+* OLT assigns to an ONU during the ONU's activation using the PLOAM channel.
+* ONU-ID is unique across the PON and remains valid until the ONU is powered off, deactivated by the OLT or moves itself into an inactive state.
+
+## Allocation Identifier (Alloc-ID)[^zyxel]
+* Alloc-ID is a 12-bit identifier (0 .. 4095) that the OLT assigns to an ONU's traffic-bearing entity.
+    * 0 .. 253 Default
+    * 254 Broadcast
+    * 255 Unassigned
+    * 256 .. 4095 Assignable
+* A Traffic-bearing entity can be represented either by a T-CONT or by the upstream OMCC.
+
+## Transmission Containers (T-CONT)[^zyxel],[^broadbandforum]
+A Transmission Container (T-CONT) is an ONU object representing a group of logical connections that appear as a single entity for the purpose of upstream bandwidth assignment on the PON.
+* Bandwidth assignment and QoS control are performed in every T-CONT by fixed and dynamic methods.
+* There are 5 types of T-CONT Traffic Descriptors:
+    * Type 1: fixed bandwidth type.
+    * Type 2 and Type 3: guaranteed bandwidth types.  
+    * Type 4: best-effort type.
+    * Type 5: mixed type, involving all bandwidth types and bearing all services
+
+| Type 1    | Type 2    | Type 3    | Type 4 | Type 5           |
+| --------- | --------- | --------- | ------ | ---------------- |
+| SIR       |           |           |        | SIR              |
+|           | AIR       | AIR       |        | AIR              |
+| PIR = SIR | PIR = AIR | PIR > AIR | PIR    | PIR >= SIR + AIR |
+
+* For TR-156 and TR-167, each T-CONT represents a traffic class
+* Each ONU is assigned at least one Alloc-ID which is equal to that ONU's ONU-ID and may be assigned additional Alloc-IDs per the OLT's discretion.
+    * Typically have 4 T-CONTs, supporting 4 traffic classes, plus one T-CONT for OMCI
+* Default Alloc-ID is used to carry the upstream PLOAM and OMCC traffic and may carry user data traffic.
+* OLT schedules upstream traffic across all ONUs according to the priority and weight assigned to each T-CONT, and their buffer occupancy. Other bandwidth assignment mechanisms are available, for example fixed bandwidth, assured bandwidth, and nonassured bandwidth[^broadbandforum].
+
+
+## Dynamic Bandwidth Allocation (DBA)
+
+{% include image.html file="quick-start\pon_dba.jpg" alt="PON DBA Abstraction" caption="PON DBA Abstraction" %}
+
+
+Dynamic Bandwidth Allocation (DBA) is a technique by which traffic bandwidth in a shared telecommunications medium can be allocated on demand and fairly between different users of that bandwidth. And it is performed on the upstream traffic[^zyxel].
+
+With DBA, the OLT assesses the bandwidth needs of the ONUs in real time and allocates upstream PON capacity accordingly[^broadbandforum].
+
+DBA basic model supports[^zyxel]:
+- Fixed bandwidth (highest priority)
+- Assured bandwidth
+- Non-assured bandwidth
+- Best-effort bandwidth (lowest priority)
+
+{% include image.html file="quick-start\bda-pratical.jpg" alt="Bandwidth Assignment practical example" caption="Bandwidth Assignment practical example" %}
+
+## GPON transmission basics[^cisco]
+
+Key Terms:
+- Physical layer overhead upstream (PLOu) - Upstream physical layer overhead.
+- Physical layer OAM upstream (PLOAMu) - PLOAM messages of upstream data. Think of this as a message-based operation and management channel between the OLT and ONU/ONTs. 
+- Power level sequence upstream (PLSu) - Upstream power level sequence 
+- Dynamic bandwidth report upstream (DBRu) - Upstream dynamic bandwidth report
+Payload - User data 
+- PCBd - Physical Control Block downstream
+- OMCC - Optical Network Unit Management and Control Channel
+- OMCI - Optical Network Unit Management and Control Interface
+
+### GPON Encapsulation
+
+GPON use two layers of encapsulation:
+
+1. TDM and Ethernet frames are wrapped into GTC Encapsulation Method (GEM) frames, which have a GFP-like format (derived from Generic Frame Procedure ITU G.7401). 
+The main purpose of the GEM frame is to provide a frame-oriented service, as an alternative to ATM, in order to efficiently accommodate Ethernet and TDM frames. With GEM, all traffic is mapped across the GPON network using a variant of SONET/SDH GFP. GEM supports a native transport of voice, video, and data without an added ATM or IP encapsulation layer[^medium],[^fs].
+2. ATM and GEM frames are both encapsulated into GTC frames that are finally transported over the PON[^medium],[^fs].
+
+ITU-T G.984 defines GEM as the only data transport scheme for GPON. Bandwidth allocation in GPON grants individual transmission opportunities to the ONU's traffic-bearing entities on the timescale of a single GTC frame[^zyxel].
+
+As shown in the image, the difference between a downstream and upstream frame. 
+
+{% include image.html file="quick-start\gtc-layer-framing.png" alt="Downstream and Upstream GTC frame" caption="Downstream and Upstream GTC frame" %}
+
+### Downstream[^zyxel],[^broadbandforum],[^cisco]
+
+{% include image.html file="quick-start\gpon-downstream.jpg" alt="GPON Downstream" caption="GPON Downstream" %}
+
+A downstream GPON frame has a fixed length of 125 μs and is 38880 bytes long which corresponds to the downstream data rate of 2.48832 Gbps, comprised of two components: physical control block downstream (PCBd) and payload.
+
+{% include image.html file="quick-start\gtc-layer-frame.png" alt="GTC Layer framing" caption="GTC Layer framing" %}
+
+The PCBd length range depends on the number of allocation structures per frame. 
+
+The OLT broadcasts PCBd to all ONU/ONTs. The ONU/ONTs receive the PCBd and performs operations based on the information received. GPON use Broadcast downstream data transmission with AES (Advanced Encryption Standard) to ensure secure delivery to destination:
+- Traffic multiplexing is centralized.
+- GEM Port-ID is the key to identify the GEM frames that belong to different downstream logical connections.
+- Only frames with the appropriate Port-IDs are allowed through to the GEM client function.
+- Each ONU filters the downstream GEM frame based on their GEM Port-ID and processes only the GEM frames that belong to that ONU.
+
+PCBd consists of the GTC header and BWmap:
+- GTC Header - Used for frame delimitation, synchronization, and forward error correction (FEC).
+- BWmap - Field notifies very ONU of upstream bandwidth allocation. Specifies the start and end upstream time slots for the T-CONTs of each ONU. This ensures that all ONUs send data based on the time slots specified by the OLT to prevent data conflict.
+
+{% include image.html file="quick-start\downstream-multiplexing.png" alt="Downstream multiplexing (shaded GEM port indicates multicast)" caption="Downstream multiplexing (shaded GEM port indicates multicast)" %}
+
+1. OLT sends Ethernet frames from Uplink ports to the GPON service processing module based on configured rules to the PON ports.
+2. GPON service processing module then encapsulates the Ethernet frames into GEM port data packets for downstream transmission. 
+3. GPON transmission convergence (GTC) frames that contain GEM PDUs are broadcast to all ONT/ONUs connected to the GPON port.
+4. ONT/ONU filters the received data based on the GEM port ID contained in the GEM PDU header and retains the data only significant to the GEM ports on this ONT/ONU.
+5. ONT decapsulates the data and sends the Ethernet frames to the end users via service ports.
+
+### Upstream[^zyxel],[^broadbandforum],[^cisco]
+
+{% include image.html file="quick-start\gpon-upstream.jpg" alt="GPON Upstream" caption="GPON Upstream" %}
+
+In the Upstream the GEM traffic is carried over one or more T-CONTs. The OLT receives the transmission associated with the T-CONT and the frames are forwarded to the GEM TC adapter and then the GEM client.
+
+- Use Time Division Multiple Access (TDMA) for upstream data transmission w/o AES encryption.
+    * Distance between the OLT and ONT/ONU is measured (Ranging):
+        * OLT starts the process on an ONU when the ONU first registers with the OLT and obtains round trip delay (RTD) of the ONU. Based on the RTD, the other key components are identified:
+        * Calculation of the physical reach of that specific ONU, as this OLT requires a proper equalization delay (EqD) for each ONU based on physical reach.
+        * RTC and EqD synchronize data frames sent by all ONUs
+    * Time slots are allocated based on distance. In order to prevent data conflict (collisions), the OLT must be able to precisely measure the distance between itself and each ONU to provide a proper time slot to facilitate data upstream. This allows the ONUs to send data at specified time slots, to prevent issues upstream. This process is achieved through a technique called ranging. 
+    * ONT/ONU sends traffic upstream based on granted time slot.
+- Dynamic Bandwidth Allocation (DBA) enables the OLT to monitor in real-time, congestion, bandwidth usage, and configuration.
+- Traffic multiplexing is distributed.
+- The OLT grants the upstream bandwidth allocation.
+- The ONU traffic-bearing entities are identified by their Allocations IDs.
+- The alloc-IDs are multiplexed in time as specified by the bandwidth-map (given by the OLT in the downstream frame).
+- Within the bandwidth allocation, the ONU uses the GEM Port-IF as key to identify upstream GEM frames.
+- Each upstream frame contains the content carried by one or more T-CONT/T-CONTs.
+- All ONUs connected to a GPON port share the upstream bandwidth.
+- All ONUs send their data upstream at their own time slots based on bandwidth map (BWmap) requirements. 
+- Each ONU reports the status of data to be sent to the OLT by use of upstream frames. OLT uses DBA to allocate upstream time slots to ONUs and sends updates in each frame.
+- Burst Technology: Upstream packet flow is achieved via bursts, with each ONU/ONT responsible for data transmission within its allocated time slots. When an ONU/ONT is not within its time slot, the device disables transmission of its optical transceiver to prevent other ONU/ONT impact. 
+
+
+{% include image.html file="quick-start\upstream-multiplexing.png" alt="Upstream multiplexing" caption="Upstream multiplexing" %}
+
+1. ONT/ONU send Ethernet frames to GEM ports based on configured rules that map service ports and GEM ports.
+2. GEM ports encapsulate the Ethernet frames into GEM PDUs and add these PDUs to T-CONT queues based on rules that map GEM ports and T-CONT queues.
+3. T-CONT queues use time slots based on DBA, then transmit upstream GEM PDUs to the OLT.
+4. OLT decapsulates the GEM PDU, the original Ethernet frame is now seen.
+5. OLT sends the Ethernet frames from a specified uplink port based on rules that map service ports and uplink ports. 
+
+## Protocol stack for the C/M-plane[^standardgpon] 
+
+The control and management plane in the GTC system consists of three parts: embedded OAM,
+PLOAM and OMCI. The embedded OAM and PLOAM channels manage the functions of the PMD
+and the GTC layers. The OMCI provides a uniform system for managing higher (service-defining)
+layers.
+
+{% include image.html file="quick-start\uplane.png" alt="The U-plane protocol stack and identification by Port-ID" caption="The U-plane protocol stack and identification by Port-ID" %}
+
+## Configuration Methods[^zyxel]
+
+Several methods are available for the installation and activation of the ONU.
+– Method A: Match serial number and password.
+– Method C: Match PLOAM password or serial number.
+– Method C-autolock: Match serial number.
+– Method D: Volatile auto provision by template.
+– Method E: Non-volatile auto provision by template.
+
+If the ONU is not legal, the ONU registration activation will fail, see [GPON Auth](/gpon-auth) for the ONU States.
+
+## Protocol Stacks[^cisco],[^fs]
+
+The GPON protocol has its own stack, just Ethernet or IP.
+
+{% include image.html file="gpon.jpg" alt="PON DBA Abstraction" caption="PON DBA Abstraction" %}
+
+### Ethernet over GEM[^standardgpon]
+
+The Ethernet frames are carried directly in the GEM frame payload. The preamble and start frame delimiter (SFD) bytes are discarded prior to GEM encapsulation. Each Ethernet frame shall be mapped to a single GEM frame (as shown in Figure) or multiple GEM frames, in which case the fragmentation rules apply.
+
+{% include image.html file="quick-start\gem_frame.jpg" alt="Frame structure for Ethernet mapping into GEM frame" caption="Frame structure for Ethernet mapping into GEM frame" %}
+
+Resolves Ethernet frames and directly maps the data of Ethernet frames into the GEM payload. GEM frames automatically encapsulate header information.
+
+1:1 alignment between an Ethernet Frame and GEM Frame. 
+
+## OMCI[^cisco]
+
+- ONU Management and Control Interface (OMCI) messages are used to discover ONT/ONUs for management and control.
+- These specialized messages are sent over dedicated GEM ports established between an OLT and an ONT/ONU.
+- The OMCI protocol allows an OLT to:
+   * Establish and release connections with the ONT.
+   * Manage the UNIs on the ONT.
+   * Request configuration information and performance statistics.
+   * Autonomously alert of events, such as a link failure.
+- Key Points:
+   * Protocol runs over a GEM connection between the OLT and ONT.
+   * GEM connection is established while the ONT initializes.
+   * Protocol operation is asynchronous - OLT controller functions as a primary, ONT controller as secondary. 
+
+### Management Information Base (MIB) and Management entities (ME's)[^arsat]
+
+A way of MIB (Management Information Base) formed by Management Entities (ME's) is used to fully describe the ONU configuration, status and several other actions
+
+OMCI constitute the protocol in order to support the set of actions performed over ONU to create; delete and other set of actions on those ME's
+
+- A Managed Entity (ME) is composed of attributes, actions and notifications defining its characteristics.
+- Managed Entity (ME Class Value)
+    - Purpose of the entity
+    - Autonomously instantiated by ONU or explicitly created by OLT
+    - Relationship(s) with other managed entities
+- Attributes: Attribute Definition
+    - ME id: This attribute provides a unique number for each instance of this managed entity.
+    - List of attributes. Attribute Number within ME Determined by the Order in Which Attributes are Listed
+- Actions: operations that may be performed on the entity (Create/Get/Set/Test, etc.)
+- Notifications (Alarm, AVC, TCA, Test Result)
+- There can be multiple instances of a Managed Entity. Each instance has the same attributes, actions and notifications even though the values of the attributes may be different from each other.
+
+### VEIP and PPTP[^huaweiveip],[^cdatatec]
+
+According to the application, ONU can be divided into six types, namely SFU (Single Family Unit) ONU, HGU (Home Gateway Unit) ONU, MDU (Multi-Dwelling Unit) ONU, SBU (Single Business Unit) ONU, MTU (Multi-Tenant Unit) ONU and CBU (Cellular Backhaul Unit) ONU. However, only SFU (Single Family Unit) ONU and HGU (Home Gateway Unit) ONU are used by the end-users in practical application.
+
+HGU ONU takes the Virtual Ethernet interface point (VEIP). Virtual Ethernet interface point (VEIP) as an OMCI administrative domain and a non-OMCI administrative domai (like TR-069). At the switchover point of the data plane, the ME can be managed only through the OMCI and is visible to the non-OMCI management domain, but not manageable. Similarly, all UNI-side modules under the VEIP are invisible to and cannot be managed by the OMCI. They are visible and manageable only to the non-OMCI management domain. In addition, each ONU should have only one VEIP.
+
+When the ONU uploads the MIB, the ONU reports only the mandatory MEs and supported optional MEs. It does not report the MEs related to LOID authentication, performance monitoring, and T-CONT MEs of the OMCC channel.
+
+The ONU should be used according to the device type and report either VEIP or PPTP during MIB upload. The SFU only uses and reports PPTP. VEIP should not be used. HGUs can only use and report VEIPs. PPTP should not be used. The OLT determines the ONU type based on the ONU Type attribute in ME:ONU Capability. Only one VEIP is allowed in each HGU. ONU will report VEIP or PPTP (Physical Path Termination Point) when MIB is uploaded according to the type of the device, while HGU can only use and report VEIP rather than PPTP. OLT will judge the type of ONU devices according to the attribution of ONU type in ONU capability.
+
+{% include image.html file="quick-start\veip.jpg" alt="Service Process of HGU ONU" caption="Service Process of HGU ONU" %}
+
+
+SFU ONU only supports the OMCI management domain. PPTP is what SFU uses and reports, while VEIP is not available. The processing mode of OMCI configured data flow is different from that of RG flow. For OMCI data flow, there is a one-to-one mapping between the GEM port on the WAN side and the UNI port on the LAN side. All data packets can pass through without MAC address learning or forwarding. Wireless interfaces are not allowed in OMCI.
+
+SFU ONU is designed for a single family unit with broadband access terminal function without a more complex home gateway function from the perspective of application and ONU capacity. SFU ONU, mainly used in FTTH scenarios, has 1 or 4 Ethernet interfaces and is available for Ethernet / IP services, optional VoIP services (built-in IAD), or CATV services.
+
+SFU ONU works under the bridging mode (layer 2 of ISO model), supports multiple VLAN functions, and its Ethernet port can be configured and managed by OLT through OMCI / OAM. Combined with a home gateway, SFU ONU is good at providing strong service capability.
+
+<hr>
+
+[^standardgpon]: *G.984.3: Gigabit-capable passive optical networks (GPON): Transmission convergence layer specification* https://www.itu.int/rec/T-REC-G.984.3
+[^fs]: *Comparison of EPON and GPON* https://community.fs.com/blog/comparison-of-epon-and-gpon.html
+[^zyxel]: *GPON E2E Fundamentals*, Zyxel 2018
+[^huawei]: *GPON Fundamentals*, Huawei 2010 http://jm.telecoms.free.fr/QCM_Fibre/GPON-Fundamentals_Huawei.pdf
+[^broadbandforum]: *GPON in FTTx Broadband Deployments*, Broadband Forum 2010 https://www.broadband-forum.org/download/MR-246.pdf
+[^wolon]: *Fiber SFP Module Compatibility with APC, UPC, PC* https://www.wolonte.com/news.asp?id=599
+[^cisco]: *Understand GPON Technology* https://www.cisco.com/c/en/us/support/docs/switches/catalyst-pon-series/216230-understand-gpon-technology.html
+[^medium]: *HTFuture: EPON vs GPON Standard* https://medium.com/@ivyhtfuture/epon-vs-gpon-standard-b8ec20c55bb3
+[^telecom]: *Fifty Years of Fixed Optical Networks Evolution: A Survey of Architectural and Technological Developments in a Layered Approach* https://doi.org/10.3390/telecom3040035
+[^huaweimultiplexing]: *GPON Principle---Data Multiplexing* https://forum.huawei.com/enterprise/en/gpon-principle-data-multiplexing/thread/458243-100181
+[^huaweiveip]: *VEIP knowledge* https://forum.huawei.com/enterprise/en/veip-knowledge/thread/771975-100181
+[^cdatatec]: *Differences between HGU ONU and SFU ONU* https://cdatatec.com/differences-hgu-onu-sfu-onu/
+[^arsat]: *Gpon: Tecnology*, ARSAT
+
diff --git a/_gpon/gpon-auth.md b/_gpon/gpon-auth.md
index c2a84fe..4336c6c 100644
--- a/_gpon/gpon-auth.md
+++ b/_gpon/gpon-auth.md
@@ -1,13 +1,13 @@
 ---
-title: GPON Auth
+title: GPON Auth (ONU Online Status)
 has_children: false
 nav_order: 3
-description: ONU Online Status
 layout: default
 ---
 
+The information on this page is taken from the GPON standard and information from the major vendors of GPON equipment, each individual item containing a verifiable citation in the standard. Feel free to cite this page as: `{{ page.title }}, Hack GPON. Available at: https://hack-gpon.github.io{{ page.url }}`.
 
-# GPON Status: Ox
+# ONU activation state: `Ox`[^huawei],[^standardgpon]
 The process for an ONU to go online unconfigured involves five states:
 
 - **`O1` Initial:** the OLT sends a message to the ONU to start the ONU, and the ONU enters the standby state;
@@ -36,12 +36,16 @@ graph TD
     O5 & O4 ---->|Deactive ONU-ID Request| O1
 ```
 
-# Fake O5 Status
+# Fake O5 Status[^anime4000]
 
 There is a known issue with Alcatel/Nokia OLTs giving fake `O5` ONU Status, OLTs will hold OMCI Provisioning until correct OMCI Information is received.
 
 It happens when the OLT detects that the ONT is `drunk`, so it tries to update the firmware before opening the GEM link. If this happens, the user has to try changing the software version or other data.
 
-- [The Process for an ONU to go Online](https://forum.huawei.com/enterprise/en/the-process-for-an-onu-to-go-online-gpon-technical-posts-12/thread/462895-100181)
-- [What’s the Authentication of GPON](http://zhangjorna.blogspot.com/2016/05/whats-authentication-of-gpon.html)
-- [`O5` No Internet](https://github.com/Anime4000/RTL960x/blob/main/Docs/fakeO5.md)
\ No newline at end of file
+This is most likely to reduce logs from misconfigured ONTs and to be able to send updates automatically to ONTs.
+
+<hr>
+
+[^huawei]: *The Process for an ONU to go Online* https://forum.huawei.com/enterprise/en/the-process-for-an-onu-to-go-online-gpon-technical-posts-12/thread/462895-100181
+[^standardgpon]: *G.984.3: Gigabit-capable passive optical networks (GPON): Transmission convergence layer specification* https://www.itu.int/rec/T-REC-G.984.3
+[^anime4000]: *`O5` No Internet* https://github.com/Anime4000/RTL960x/blob/main/Docs/fakeO5.md
\ No newline at end of file
diff --git a/_gpon/ont.md b/_gpon/ont.md
index 98471fe..84bb558 100644
--- a/_gpon/ont.md
+++ b/_gpon/ont.md
@@ -1,23 +1,37 @@
 ---
-title: ONT
+title: GPON ONT Chipset
 has_children: false
 nav_order: 2
-description: Resources to access and modify ONTs
 layout: default
 ---
 
 
 # Major Chipset Manufacturers
 
-Currently, there are only two main GPON chipset vendors:
+Currently, there are only a few main GPON chipset vendors:
 
-- Realtek manufactures these chipsets:
-    * RTL9601B  
-    * RTL9601CI (HSGMII)
-    * RTL9601D (HSGMII)
-- Lantiq used to manufacture these chipsets:
+- Realtek:
+    * RTL9601 (for ONT)
+        - RTL9601B  
+        - RTL9601CI (HSGMII)
+        - RTL9601D (HSGMII)
+    * RTL9602/RTL9603 series (for router with integrated PON)
+    * Cortina QWCS8032E
+- Lantiq:
     * PEB98035 (HSGMII)
     * PEB98036
+- ZTE:
+    * FA626TE 
+    * ZX279110a1
+    * ZX279125
+- HiSilicon (Huawei)
+    * SD5116
+- Marvell 
+    * 88F6601
+- Broadcom
+    * BCM68 series
+- MediaTek/Econet
+    * MT/EN752 series (EN7520T HSGMII)
 
 ## Realtek Chipsets
 
diff --git a/_gpon/vendor.md b/_gpon/vendor.md
index 31a1457..7e5a538 100644
--- a/_gpon/vendor.md
+++ b/_gpon/vendor.md
@@ -1,11 +1,11 @@
 ---
-title: PON Vendor ID
+title: ONU Vendor ID
 has_children: false
 nav_order: 4
 layout: default
 ---
 
-> 4 ASCII character maximum
+> 4 ASCII character
 
 Needs to be set for the OLT to authenticate your ONT; please read your original ONT's Serial Number, it can be either in HEX or ASCII: if it's codified in HEX, you need to convert the first eight HEX digits to ASCII, for example `48575443` = `HWTC`.
 
@@ -15,6 +15,7 @@ Here is a list of the most popular Vendor IDs:
 | ID     | Vendor Name          |
 | ------ | -------------------- |
 | `ALCL` | Nokia/Alcatel-Lucent |
+| `CIGG` | Cig                  |
 | `DLNK` | Dlink                |
 | `ELTX` | Eltex                |
 | `FHTT` | Fiber Home           |
@@ -35,3 +36,5 @@ Here is a list of the most popular Vendor IDs:
 | `UBNT` | Ubiquiti             |
 | `ZTEG` | ZTE                  |
 | `ZYWN` | Zyxel                |
+
+{% include alert.html content="You can also help us with the content of this site, on each page you will find a button to edit on GitHub." alert="Tip"  icon="svg-info" color="green" %}
\ No newline at end of file
diff --git a/_ont/ont-huawei-hg8010h.md b/_ont/ont-huawei-hg8010h.md
index 66c99b5..2e6cdce 100644
--- a/_ont/ont-huawei-hg8010h.md
+++ b/_ont/ont-huawei-hg8010h.md
@@ -11,7 +11,7 @@ parent: Huawei
 | ----------- | ---------------------------------------------------------------------------------------------- |
 | Vendor      | Huawei                                                                                         |
 | Model       | HG8010H                                                                                        |
-| Chipset     | Hisilicon                                                                                      |
+| Chipset     | HiSilicon SD5116                                                                               |
 | Flash       | 128MiB (SLC NAND DS35Q1GA-IB)                                                                  |
 | RAM         | 256MiB                                                                                         |
 | CPU         | Hisilicon A9 dual core (ARMv7)                                                                 |
diff --git a/_ont/ont-zyxel-pmg5100-t0.md b/_ont/ont-zyxel-pmg5100-t0.md
index 301d3ee..f1d853c 100644
--- a/_ont/ont-zyxel-pmg5100-t0.md
+++ b/_ont/ont-zyxel-pmg5100-t0.md
@@ -7,27 +7,28 @@ parent: Zyxel
 
 # Hardware Specifications
 
-|             |                 |
-| ----------- | --------------- |
-| Vendor      | Zyxel           |
-| Model       | PM5100-T0       |
-| Chipset     | MediaTek/EcoNet |
-| Flash       |                 |
-| RAM         |                 |
-| System      |                 |
-| 2.5GBaseT   | Yes             |
-| Optics      | SC/APC          |
-| IP address  |                 |
-| Web Gui     | ✅              |
-| SSH         | ✅              |
-| Form Factor | ONT             |
+|             |                          |
+| ----------- | ------------------------ |
+| Vendor      | Zyxel                    |
+| Model       | PM5100-T0                |
+| Chipset     | MediaTek/EcoNet EN7523OT |
+| Flash       |                          |
+| RAM         |                          |
+| System      |                          |
+| 2.5GBaseT   | Yes                      |
+| Optics      | SC/APC                   |
+| IP address  |                          |
+| Web Gui     | ✅                       |
+| SSH         | ✅                       |
+| Form Factor | ONT                      |
+
 
 {% include image.html file="zyxel-pmg5100\front.jpg" alt="PM5100-T0" caption="PM5100-T0" %}
 {% include image.html file="zyxel-pmg5100\back.jpg" alt="PM5100-T0" caption="PM5100-T0" %}
 {% include image.html file="zyxel-pmg5100\port.jpg" alt="PM5100-T0" caption="PM5100-T0" %}
 {% include image.html file="zyxel-pmg5100\front.jpg" alt="PM5100-T0" caption="PM5100-T0" %}
 {% include image.html file="zyxel-pmg5100\back-board.jpg" alt="PM5100-T0 Teardown" caption="PM5100-T0 Teardown" %}
-{% include image.html file="zyxel-pmg5100\port-board.jpg" alt="PM5100-T0 Teardown" caption="PM5100-T0 Teardown" %}
+{% include image.html file="zyxel-pmg5100\front-board.jpg" alt="PM5100-T0 Teardown" caption="PM5100-T0 Teardown" %}
 
 ## List of software versions
 ## List of partitions
diff --git a/assets/img/epon_gpon.jpg b/assets/img/epon_gpon.jpg
new file mode 100644
index 0000000..816871c
--- /dev/null
+++ b/assets/img/epon_gpon.jpg
diff --git a/assets/img/gpon.jpg b/assets/img/gpon.jpg
new file mode 100644
index 0000000..b82573e
--- /dev/null
+++ b/assets/img/gpon.jpg
diff --git a/assets/img/quick-start/bda-pratical.jpg b/assets/img/quick-start/bda-pratical.jpg
new file mode 100644
index 0000000..8d172bf
--- /dev/null
+++ b/assets/img/quick-start/bda-pratical.jpg
diff --git a/assets/img/quick-start/gem_frame.jpg b/assets/img/quick-start/gem_frame.jpg
new file mode 100644
index 0000000..2808733
--- /dev/null
+++ b/assets/img/quick-start/gem_frame.jpg
diff --git a/assets/img/quick-start/pon_dba.jpg b/assets/img/quick-start/pon_dba.jpg
new file mode 100644
index 0000000..c98a332
--- /dev/null
+++ b/assets/img/quick-start/pon_dba.jpg
diff --git a/assets/img/quick-start/veip.jpg b/assets/img/quick-start/veip.jpg
new file mode 100644
index 0000000..a17664b
--- /dev/null
+++ b/assets/img/quick-start/veip.jpg
diff --git a/quick-start.md b/quick-start.md
index 51c9bee..a20cc72 100644
--- a/quick-start.md
+++ b/quick-start.md
@@ -5,12 +5,13 @@ nav_order: 2
 description:  
 layout: default
 ---
+{% include alert.html content="Playing with ONTs can cause your serial number/PLOAM password to be banned and faults to the optics, ONTs and OLTs. Always pay close attention to the calibration of the laser, under no circumstances should the calibration be changed." alert="Warning" icon="svg-warning" color="red" %}
 
-{% include alert.html content="Playing with ONTs can cause your serial number/PLOAM password to be banned and faults to the optics, ONTs and OLTs. Always pay close attention to the calibration of the laser, under no circumstances should the calibration be changed." alert="Warning"  icon="svg-warning" color="red" %}
+The information on this page is taken from the GPON/EPON standard and information from the major vendors of GPON/EPON equipment, each individual item containing a verifiable citation in the standard. Feel free to cite this page as: `{{ page.title }}, Hack GPON. Available at: https://hack-gpon.github.io{{ page.url }}`.
 
 # Fiber Optic Connectors
 
-Numerous connectors, both standard and proprietary, are used in the field of telecommunication equipment, data lines, television and cable, and other industrial fields. 
+Numerous connectors, both standard and proprietary, are used in the field of telecommunication equipment, data lines, television and cable, and other industrial fields. 
 
 {% include image.html file="quick-start\optic-fiber-connectors.jpg"  alt="Some of the common connector" caption="Some of the common connector" %}
 
@@ -33,48 +34,73 @@ The main connector are:
 
 ## Polishing of Fiber Optic Connectors
 
-APC and UPC are different polishing of fiber optic ferrules, and are types of fiber patch cable connectors. Which determine the quality of the fiber optic lightwave transmission, mostly performed in optical return loss and insertion loss.
+APC and UPC are different polishing of fiber optic ferrules, and are types of fiber patch cable connectors. Which determine the quality of the fiber optic lightwave transmission, mostly performed in optical return loss and insertion loss[^wolon].
 
 {% include image.html file="quick-start\apc-upc.jpg" alt="Picture of APC and UPC" caption="Picture of APC and UPC" %}
 
-Angled physical connectors are used in the ONT side to reduce back reflections. In
-case RF signal (1550nm) is introduced there will be two signals traveling in the
-downstream direction (1490nm + 1550nm), since RF systems are highly sensitive to
-reflections then the APC connectors reduce the return loss value.
+Angled physical connectors are used in the ONT side to reduce back reflections. In case RF signal (1550nm) is introduced there will be two signals traveling in the downstream direction (1490nm + 1550nm), since RF systems are highly sensitive to reflections then the APC connectors reduce the return loss value[^zyxel].
 
-Next generation systems are planned to operate in over 1500nm wavelengths,
-converting APC connectors on the ONT side into planning to the future.
+Next generation systems are planned to operate in over 1500 nm wavelengths, converting APC connectors on the ONT side into planning to the future[^zyxel].
 
-
-
-# PON Networks
+# PON Networks[^huawei]
 
 - PON is a kind of passive optical network featuring one-to-multiple-point architecture;
 - PON is short for Passive Optical Network;
-- PON consists of Optical Line Terminal (OLT), Optical Network Unit (ONU) and
-Passive Optical Splitter.
+- PON consists of Optical Line Terminal (OLT), Optical Network Unit (ONU) and Passive Optical Splitter.
 
-- APON: ATM Passive Optical Networks
-- EPON: Ethernet Passive Optical Networks
-- GPON: Gigabit-capable Passive Optical Networks
-- XG(S)-GPON: 10 Gigabit-capable Passive Optical Networks
+- APON: ATM Passive Optical Networks;
+- EPON: Ethernet Passive Optical Networks;
+- GPON: Gigabit-capable Passive Optical Networks;
+- XG(S)-GPON: 10 Gigabit-capable Passive Optical Networks[^standardxgpon];
+
+EPON and GPON are complementary and compete against each other in some aspects. So in the following contents, we'd like to make clear the EPON and GPON comparison [^fs].
 
 ## Why GPON?
 
-- GPON supports Triple - play service, providing competitive all-service solution.
-- GPON supports high-bandwidth transmission to break down the bandwidth
-bottleneck of the access over twisted pair cables, so as to satisfy the
-requirements of high-bandwidth services, such as IPTV and live TV broadcasts.
-- GPON supports the long-reach (up to 20 km) service coverage to overcome the
-obstacle of the access technology over twisted pair cables and reduce the
-network nodes.
-- With complete standards and high technical requirements, GPON supports
-integrated services in a good way.
-GPON is the choice of large carriers in the international market.
+- GPON is defined by ITU, International Telecomunication Union[^standardgpon].
+- GPON supports Triple - play service, providing competitive all-service solution[^huawei].
+- GPON supports high-bandwidth transmission to break down the bandwidth bottleneck of the access over twisted pair cables, so as to satisfy the requirements of high-bandwidth services, such as IPTV and live TV broadcasts[^huawei].
+- GPON supports the long-reach (up to 20 km) service coverage to overcome the obstacle of the access technology over twisted pair cables and reduce the network nodes[^huawei].
+- With complete standards and high technical requirements, GPON supports integrated services in a good way[^huawei].
+- GPON is the choice of large carriers in the international market[^huawei].
+- GPON is high broadband efficiency, like 92%[^huawei].
+- GPON has integrated QoS handling that makes it better than EPON, because EPON QoS is high cost relative to GPON[^fs].
+- GPON supports splitting up to 1:128, XG(S)-PON up to 1:256[^fs],[^standardxgpon].
+- Security: the data transmitted down to ONUs/ONTs are encrypted based on the AES mechanism[^telecom].
+
+
+## Why EPON?
+- EPON is defined by IEEE 802.3 standard, ratified as 802.3ah-2004 for 1.25 Gbps (1.0 Gbps prior to 8B/10B coding) and IEEE 802.3av standard for 10Gbps (10G-EPON)[^standard1epon],[^standard10epon].
+- 1/1-EPON supports splitting up to 1:32, 10/*-EPON up to 1:128[^fs],[^standard10epon].
+- In EPON, both downstream and upstream line rates are 1.25 Gbps, but due to the 8B/10B line encoding, the bit rate for data transmission is 1 Gbps[^medium].
+- The use of EPON allows carriers to eliminate complex and expensive ATM and Sonet elements and to simplify their networks, thereby lowering costs to subscribers. Currently, GPON equipment costs are approximately 1.5 to 2 times higher than an EPON[^medium],[^fs].
+
+## Layer 
+
+Layering model and the associated management services are all mapped over Ethernet (directly or via IP). 
 
+- GPON support the encapsulation of other protocols besides Ethernet, such as ATM[^cisco],[^huawei],[^fs].
+- XG(S)-PON remove the support of ATM encapsulation[^telecom].
+- GPON use two layers of encapsulation are required. First, TDM and Ethernet frames are wrapped into GTC Encapsulation Method (GEM) frames, which have a GFP-like format (derived from Generic Frame Procedure ITU G.7401). Secondly, ATM and GEM frames are both encapsulated into GTC frames that are finally transported over the PON[^medium],[^fs].
+- The main purpose of the GEM frame is to provide a frame-oriented service, as an alternative to ATM, in order to efficiently accommodate Ethernet and TDM frames. With GEM, all traffic is mapped across the GPON network using a variant of SONET/SDH GFP. GEM supports a native transport of voice, video, and data without an added ATM or IP encapsulation layer. That's why GPON supports downstream rates as high as 2.5 Gbps and upstream rates from 155 Mbps to 2.5 Gbps. It is much faster than EPON[^medium]. 
+- However, EPON clearly offers a much simpler and more straightforward solution than GPON. The support of ATM and the double encapsulation of GPON serve no real benefit over a pure Ethernet transport scheme[^medium].
+- In EPON, Ethernet frames are carried in their native format on the PON, which greatly simplifies the layering model and the associated management. EPON employs a single layer that uses IP (Internet Protocol) to carry data, voice, and video[^medium],[^fs].
 
+{% include image.html file="epon_gpon.jpg"  alt="EPON vs GPON Layer" caption="EPON vs GPON Layer" %}
 
-# Wavelength
+## Comunication between ONT and OLT[^fs]
+
+- EPON utilizes IEEE 802.3ah OAM messages for provisioning, fault isolation and performance monitoring in conjunction with SNMP (Simple Network Management Protocol) sets and gets through IETF (Internet Engineering Task Force) and MIBs (Management Information Bases). Additional control messages are MPCP GATEs/REPORTs for bandwidth granting.
+- In GPON there are three different types of control messages: OMCI (ONT Management and Control Interface), OAM, and PLOAM (Physical Layer OAM). Their roles are shown in the table below.
+
+| Control channel | Format          | Used for                                                                                                           |
+| --------------- | --------------- | ------------------------------------------------------------------------------------------------------------------ |
+| OMCI            | Ethernet or ATM | Provisioning of ONT service defining layers above the GTC                                                          |
+| Embedded OAM    | Header overhead | BW granting, encryption key switching, and DBA                                                                     |
+| PLOAM           | ATM             | Auto discovery and all other PMD and GTC management info. PLOAM messages are directed to ONTs or FF for broadcasts |
+
+
+## Wavelength[^huaweimultiplexing]
 
 PON adopts Wavelength Division Multiplexing (WDM) technology, facilitating bi-direction communication over a single fiber.
 
@@ -84,22 +110,14 @@ To separate upstream/downstream signals of multiple users over a single fibre, P
 
 {% include image.html file="quick-start\optical-fiber-transmission-windows.svg"  alt="Fiber Optic Operation Wavelength and Window" caption="Fiber Optic Operation Wavelength and Window" %}
 
-In GPON and 1/1-EPON:
-- Upstream 1310 nm (1260 nm-1360 nm)
-- Downstream 1490 nm (1480 nm-1500 nm)
-- RF-Overlay 1550 nm (1550 nm-1560 nm)
-
-In 10/1-EPON:
-- Upstream 1310 nm (1260 nm-1360 nm)
-- Downstream 1577.5 nm (1575 nm-1580 nm)
-- RF-Overlay 1550 nm (1550 nm-1560 nm)
 
-In XG(S)-GPON and 10/10-EPON:
-- Upstream 1270 nm (1260 nm-1280 nm)
-- Downstream 1577.5 nm (1575 nm-1580 nm) 
-- RF-Overlay 1550 nm (1550 nm-1560 nm)
+|            | GPON                      | 1/1-EPON                  | XG(S)-GPON                  | 10/1-EPON                   | 10/10-EPON                  |
+| ---------- | ------------------------- | ------------------------- | --------------------------- | --------------------------- | --------------------------- |
+| Upstream   | 1310 nm (1260 nm-1360 nm) | 1310 nm (1260 nm-1360 nm) | 1270 nm (1260 nm-1280 nm)   | 1310 nm (1260 nm-1360 nm)   | 1270 nm (1260 nm-1280 nm)   |
+| Downstream | 1490 nm (1480 nm-1500 nm) | 1490 nm (1480 nm-1500 nm) | 1577.5 nm (1575 nm-1580 nm) | 1577.5 nm (1575 nm-1580 nm) | 1577.5 nm (1575 nm-1580 nm) |
+| RF-Overlay | 1550 nm (1550 nm-1560 nm) | 1550 nm (1550 nm-1560 nm) | 1550 nm (1550 nm-1560 nm)   | 1550 nm (1550 nm-1560 nm)   | 1550 nm (1550 nm-1560 nm)   |
 
-# Power Budget 
+# Power Budget[^zyxel],[^cisco]
 
 - Splitter attenuation
 
@@ -117,84 +135,28 @@ In XG(S)-GPON and 10/10-EPON:
 
 - Connector attenuation: ≤ 0.3 dB (Per Connector)
 
-# G.984 Series
-
-| G.984.1                 | G.984.2                             | G.984.3                        | G.984.4                            |
-| ----------------------- | ----------------------------------- | ------------------------------ | ---------------------------------- |
-| General Characteristics | Physical Media Dependant Layer      | Transmission Convergence Layer | ONT Management & Control Interface |
-| Architecture            | Bit Rate/coding                     | GTC Protocol                   | Reference model                    |
-| Distance/Reach          | Wavelength                          | GTC Framing                    | OMCI requirement                   |
-| Split Ratio             | Optical element specs and operation | ONU Activation                 | MIBs                               |
-| Protection              | Link budget (amendment)             | Security / FEC                 | OMCC                               |
-|                         |                                     | Alarms / Monitoring            |                                    |
-|                         |                                     | OMCI                           |                                    |
-
-## General Concepts
-
-- Bit Rate: 1.2Gbit/s Upstream; 2.4Gbit/s Downstream.
-- Physical Reach: Max physical distance between OLT and ONT.
-- Differential Fiber Distance: Distance between closest and farthest ONT from OLT (max = 20km.)
-
-### GPON Terminology
-- ONU Identifier (ONU-ID)
-    * 8 bit identifier (0~255)
-        * 0 .. 253 Assignable
-        * 254 Reserved
-        * 255 Broadcast/unassigned
-    * OLT assigns to an ONU during the ONU's activation using the PLOAM channel.
-    * ONU-ID is unique across the PON and remains valid until the ONU is powered off,
-    deactivated by the OLT or moves itself into an inactive state.
-- Allocation Identifier (Alloc-ID).
-    * Alloc-ID is a 12-bit identifier (0 .. 4095) that the OLT assigns to an ONU’s traffic-bearing entity.
-        * 0 .. 253 Default
-        * 254 Broadcast
-        * 255 Unassigned
-        * 256 .. 4095 Assignable
-    * A Traffic-bearing entity can be represented either by a T-CONT or by the upstream OMCC.
-        * A Transmission Container (T-CONT) is an ONU object representing a group of logical connections that appear as a single entity for the purpose of upstream bandwidth assignment on the PON.
-        * Bandwidth assignment and QoS control are performed in every T-CONT by fixed and dynamic methods.
-        * There are 5 types of T-CONT Traffic Descriptors:
-            *  Type 1: fixed bandwidth type.
-            *  Type 2 and Type 3: guaranteed bandwidth types.  
-            *  Type 4: best-effort type.
-            *  Type 5: mixed type, involving all bandwidth types and bearing all services
-    * Each ONU is assigned at least one Alloc-ID which is equal to that ONU's ONU-ID and may be assigned additional Alloc-IDs per the OLT's discretion.
-    * Default Alloc-ID is used to carry the upstream PLOAM and OMCC traffic and may carry user data traffic.
-- Transmission Containers (TCONT).
-- Dynamic Bandwidth Allocation (DBA).
-
-{% include image.html file="quick-start\gpon-terminology.png" alt="GPON Terminology" caption="GPON Terminology" %}
-
-{% include image.html file="quick-start\gtc-layer-frame.png" alt="GTC Layer framing" caption="GTC Layer framing" %}
-
-{% include image.html file="quick-start\gtc-layer-frame.png" alt="Downstream GTC frame" caption="Downstream GTC frame" %}
-
-{% include image.html file="quick-start\gpon-downstream.jpg" alt="GPON Downstream" caption="GPON Downstream" %}
-
-GPON use Broadcast downstream data transmission with AES (Advanced Encryption
-Standard) to ensure secure delivery to destination:
-- Traffic multiplexing is centralized.
-- GEM Port-ID is the key to identify the GEM frames that belong to different downstream logical connections.
-- Each ONU filters the downstream GEM frame based on their GEM Port-ID and processes only the GEM frames that belong to that ONU.
-- Shaded GEM ports on the figure indicate multicast.
-
-{% include image.html file="quick-start\downstream-multiplexing.png" alt="Downstream multiplexing (shaded GEM port indicates multicast)" caption="Downstream multiplexing (shaded GEM port indicates multicast)" %}
-
-- Downstream, the GEM frames are carried in the GTC payload and arrive at all the ONUs. The ONU framing sublayer extracts the frames, and the GEM TC adapter filters the frames based on their GEM Port-ID. Only frames with the appropriate Port-IDs are allowed through to the GEM client function.
-- Upstream, the GEM traffic is carried over one or more T-CONTs. The OLT receives the transmission associated with the T-CONT and the frames are forwarded to the GEM TC adapter and then the GEM client.
-
-{% include image.html file="quick-start\uplane.png" alt="The U-plane protocol stack and identification by Port-ID" caption="The U-plane protocol stack and identification by Port-ID" %}
-
-{% include image.html file="quick-start\gpon-upstream.jpg" alt="GPON Upstream" caption="GPON Upstream" %}
-- Use Time Division Multiple Access (TDMA) for upstream data transmission with AES
-encryption.
-- Dynamic Bandwidth Allocation (DBA).
-- Traffic multiplexing is distributed.
-- The OLT grants the upstream bandwidth allocation.
-- The ONU traffic-bearing entities are identified by their Allocations IDs.
-- The alloc-IDs are multiplexed in time as specified by the bandwidth-map (given by the OLT in the downstream frame).
-- Within the bandwidth allocation, the ONU uses the GEM Port-IF as key to identify upstream GEM frames
-
-{% include image.html file="quick-start\upstream-multiplexing.png" alt="Upstream multiplexing" caption="Upstream multiplexing" %}
-
+# Classes for laser[^cisco]
+
+|              | Class A | Class B | Class B+ | Class C |
+| ------------ | ------- | ------- | -------- | ------- |
+| Minimum loss | 5 dB    | 10 dB   | 13 dB    | 15 dB   |
+| Maximun loss | 20 dB   | 25 dB   | 28 dB    | 30 dB   |
+
+The requirements of a particular class may be more stringent for one system type than for another.
+
+<hr>
+
+[^standardgpon]: *G.984.1: Gigabit-capable passive optical networks (GPON): General characteristics* https://www.itu.int/rec/T-REC-G.984.1
+[^standardxgpon]: *G.987.1: 10-Gigabit-capable passive optical networks (XG-PON): General requirements* https://www.itu.int/rec/T-REC-G.987.1
+[^standard1epon]: *IEEE 802.3ah-2004: IEEE Standard for Information technology-- Local and metropolitan area networks-- Part 3: CSMA/CD Access Method and Physical Layer Specifications Amendment: Media Access Control Parameters, Physical Layers, and Management Parameters for Subscriber Access Networks* https://standards.ieee.org/ieee/802.3ah/3179/
+[^standard10epon]: *IEEE 802.3av-2009: IEEE Standard for Information technology-- Local and metropolitan area networks-- Specific requirements-- Part 3: CSMA/CD Access Method and Physical Layer Specifications Amendment 1: Physical Layer Specifications and Management Parameters for 10 Gb/s Passive Optical Networks* https://standards.ieee.org/ieee/802.3av/4060/
+[^fs]: *Comparison of EPON and GPON* https://community.fs.com/blog/comparison-of-epon-and-gpon.html
+[^zyxel]: *GPON E2E Fundamentals*, Zyxel 2018
+[^huawei]: *GPON Fundamentals*, Huawei 2010  http://jm.telecoms.free.fr/QCM_Fibre/GPON-Fundamentals_Huawei.pdf
+[^broadbandforum]: *GPON in FTTx Broadband Deployments*, Broadband Forum 2010 https://www.broadband-forum.org/download/MR-246.pdf
+[^wolon]: *Fiber SFP Module Compatibility with APC, UPC, PC* https://www.wolonte.com/news.asp?id=599
+[^cisco]: *Understand GPON Technology* https://www.cisco.com/c/en/us/support/docs/switches/catalyst-pon-series/216230-understand-gpon-technology.html
+[^medium]: *HTFuture: EPON vs GPON Standard* https://medium.com/@ivyhtfuture/epon-vs-gpon-standard-b8ec20c55bb3
+[^telecom]: *Fifty Years of Fixed Optical Networks Evolution: A Survey of Architectural and Technological Developments in a Layered Approach* https://doi.org/10.3390/telecom3040035
+[^huaweimultiplexing]: *GPON Principle---Data Multiplexing* https://forum.huawei.com/enterprise/en/gpon-principle-data-multiplexing/thread/458243-100181