FTTH internal coding implementation
Overview
This is the coding guideline for FTTH + DSL + WiFi implementation in NMS Prime.
This is the hottest topic regarding our actual work. The space will change on a daily basis.
The challenge
TR-69 is a provisioning protocol for CPE's only. This implies there is no standardised way of how to set Modem speed rates (e.g. Downstream/Upstream rate 100MBit/s to 10MBit/s). Many operator address this by using a quick-and-dirty method of manually setting internet speeds at the OLT directly via CLI. The next logical step is easy but also dirty: using the CRM to somehow "connect via telnet or SSH and push the required speed rates via CLI (or better SNMP)". This will work but it comes at a high price, imagine:
disadvantages for setting the modem speed via CLI:
- Every network architecture (GPON, Active Ethernet, DSL, WiFi) requires a different provisioning implementation
- vendor specific CLI commands (or SNMP MIBs) makes life hard for a generic implementation approach – switching OLT vendor will cause pain!
- ONU –> OLT port mapping required
support team needs knowledge of FTTH connection circuits (ineffective/bad workflow!) - potential config race conditions / hazards
Assume you are connected via SSH towards your OLT, while the provisionig system pushes also config changes via telnet/SSH. This could lead to race conditions, especially while saving configs.
Definitions
| Protocol | Usage | Provisioning of |
|---|---|---|
| TR-69 | protocol for remote management of customer-premises equipment (CPEs) | CPEs only! |
| PPPoE | The Point-to-Point Protocol over Ethernet (PPPoE) is a network protocol for encapsulating PPP frames inside Ethernet frames. (wikipedia) | speed provisioning and monitoring for any device (DSL, GPON, AE, ..) of used bandwidths |
Naming Conventions
| shortcut | usage | |
|---|---|---|
| AE | Active Ethernet | |
OLT ONU | Optical Line Terminal Optical Network Unit | |
| DSLAM | DSL Head End |
The solution:
The solution is PPPoE with the following architecture
- OLT / AE / DSLAM serves all Modems with a default profile of maximum speed, e.g. 1GBit/s down and upstream
- a BRAS / BNG router with PPPoE is used for traffic shaping and bandwidth monitoring
- customer devices require to use PPPoE protocol for dial-in
- Switches can be configured to only allow forwarding of PPPoE traffic
Dial-in Workflow
- PPPoE connection establishment
- PPPoE server forwards user/psw to RADIUS server
- RADIUS server checks credentials and looks-up RADIUS attributes of customer in database
- Establish PPPoE tunnel
5. / 6. / 8. / 9. Accounting related (optional for bandwidth monitoring)
