bbf-wt451-polt-sim

pOLT Simulator for Broadband Forum WT-451 vOMCI project

The project implements pOLT interfaces defined in WT-451 vOMCI Interface Specifications.

At its NBI pOLT implements the following interfaces:

NETCONF/YANG interface

bbf-polt-vomci.yang ---- client and server endpoints ---- client and server filters
generates remote-endpoint-connected/disconnected notification as defined in YMVOMCI-11
generates bbf-xpon-onu-states:onu-state-change notification (simulation mode only)

gRPC interface

Client and Server that can be active simultaneously. Multiple client remote-endpoints and server listen-endpoints can be provisioned via YANG interface or using CLI commands
Both pOLT gRPC client and pOLT gRPC server support OmciFunctionHelloSbi and OmciFunctionMessageSbi services defined in WT-451 vOMCI Interface Specifications
Both gRPC client and gRPC server support secured and unsecured connection. By default connections are unsecured. In order to create/expect secure connection cerificate file locations must be provisioned using CLI command
new/dropped connactions are reported using NETCONF notifications defined in YMVOMCI-11

Simulation functions:

pOLT is provided with simulation vendor sublayer (See "Vendor interface" below). This sublayer is controlled by CLI commands that allow to

add/remove ONU. These CLI commands populate the internal data base and also provoke sending NETCONF notification bbf-xpon-onu-states:onu-state-change
set receive-from-vOMCI handling mode. The following modes are supported:
- discard: OMCI packets received from vOMCI are silently discarded
- loopback :
  - OMCI packets that don't require acknowledge (AR bit in OMCI header is not set) are silently discarded
  - For every +1 packets that require acknowledge
    - discard packets
    - toggle AR and AK bits in packet +1 and send it back to vOMCI as if received from ONU
- onu_sim <remote_IP_address> <remote_port> [local_port]: Forward packets to/from ONU simulator via UDP socket. The packets have the following format: - char cterm_name[30] - uint16_t onu_id; // in network order -

HowTo Build

The build machine must have gcc, g++, make, cmake and wget installed. Provided that these prerequisites are met, the build is invoked using "make" command. It will pull a number of third party packages, such as grpc, openssh, libssh, netopeer2, etc. from their repositories, build them and then build pOLT simulator. The 1st build takes a while because of those bit 3rd party packages. Once the build is complete, build artifacts are located in build/fs subdfirectory.

Build artifacts

All build artifacts are created in build/fs directory. The following artifacts are relative to build/fs.

bcmolt_netconf_server - pOLT executable implementing all the interfaces above
start_netconf_server.sh - a simple shell script for starting bcmolt_netconf_server
tr451_polt_daemon - pOLT executable implementing only gRPC and CLI interfaces above (no NETCONF/YANG)
start_tr451_polt.sh - a simple shell script for starting tr451_polt_daemon
daemon_attach - a small application allowing to "attach" to a daemon running in the background and use CLI. Note that although daemon_attach gives access to daemon's CLI interface, line editing is limited and TAB completion is not supported.
lib/ - third-party packages compiled as shared libraries
bin/ - executables provided by third-party libraries (such as sysrepoctl, etc.)
sysrepo/ - sysrepo repository

Starting the application

The following commands are relative to build/fs directory.

netopeer2-server must be started first. It can be done using bin/start_netconf_server.sh script.

> bin/start_netconf_server.sh [netopeer2-server parameters]

By default netopeer2-server is listening on non-standard port 10830 (instead of the standard 830). It allows starting the server from regular user. Use "-help" to get the list of supported parameters

netopeer2-cli can be used for WT-451 NETCONF configuration. Alternatively, any other compliant netconf client can be used (for example, "Atom" by Nokia)

> bin/sysrepotool.sh bin/netopeer2-cli

A few relevant netopeer2-cli commands are below

connect --port 10830
subscribe
edit-config --target running --defop merge --test test-then-set --config=../../netconf_server/bbf-vomci-cli-examples/1-set-tr451-server.yc
edit-config --target running --defop merge --test test-then-set --config=../../netconf_server/bbf-vomci-cli-examples/2-add-interfaces-olt.yc

Start pOLT simulator

./start_netconf_server.sh [parameters]

Below is output of "start_netconf_server.sh -help" command.
bcmolt_netconf_server [-d] [-dummy_tr385] [-log level] [-srlog level] [-tr451_polt_log level] [-syslog]
  -d - debug mode. Stay in the foreground
  -dummy_tr385 - Dummy TR-385 management. Register for some TR-385 events
  -syslog - log to syslog
  -tr451_polt_log error|info|debug TR-451 pOLT log level
  -log error|info|debug - netconf server log level
  -srlog error|info|debug - sysrepo log level
Parameters are self-explanatory.
"-d" is recommented because using CLI in foreground mode is much more convenient

CLI interface

pOLT simulator supports CLI interface with built-in help, history and TAB completion. CLI commands are organized hierarchically in directories.

To change directory type its name or any unique abbreviation
To execute command without changing current directory type fully qualified command name (ie /dir1/dir2/cmd)
To return to the main directory use "/"
To return to the parent directory use ".."
To print help for a command use "? command"
Command can be invoked by any unique abbreviation starting from the 1st character, or using a single character that is capitalized in command name

Below are commands that are relevant for operating pOLT simulator:

Set logging level /log/name LOG_ID PRINT_LEVEL FILE_LEVEL whereas the relevant LOG_IDs are: POLT, NETCONF PRINT_LEVEL and FILE_LEVEL values are: DEBUG, INFO, ERROR. PRINT_LEVEL controls output on the screen. FILE_LEVEL controls output to a memory file or syslog.
/Polt - pOLT debug directory contains the following commands. The parameters are self-explanatory:

?
Directory Polt/ - pOLT Debug
Commands:
    Set_state(2 parms): Enable/disable client/server subsystem
    Endpoint_create(4 parms): Create a client/server endpoint
    endpoint_Delete(2 parms): Delete a client/server endpoint
    Filter(7 parms): Create a client/server filter
    Auth(3 parms): Set authentication keys
    sTats(0 parms): Print statistics
    Onu_add(3 parms): Add ONU
    oNu_delete(3 parms): Delete ONU
    Inject(3 parms): Inject OMCI packet received from ONU
    Rx_mode(1 parms): Set Receive handling mode

NOTE: if vOMCI instance should communicate with pOLT simulator using authenticated connection, private key and certificate location must be set using "/polt/auth" CLI command BEFORE creating the relevant client and/or server endpoint.

Implementation

Implementation is split in 2 parts. The first part handles NETCONF/YANG interfaces. It is implemented as a sysrepo2 application.

NETCONF server

Of-the-shelf netopeer2-server application handles NETCONF/YANG messages received via ssh or tls. netopeer2-server uses sysrepo2 APIs to provoke data change events.
sysrepo2 generates a series of events that are "forwarded" waiting application(s) via registered callback functions.
Application response (OK or failure with error message) is propagated by sysrepo2 back to netopeer2-server, which in turn generates NETCONF response.
"Notifications" are provoked by sysrepo2 applications and forwarded by sysrepo2 engine to netopeer2-server, similarly to responses.

The NETCONF/YANG part of TR-451 pOLT simulator is located in netconf_server/ directory

netconf_server/
├── bcmolt_netconf_server.c
├── CMakeLists.txt
├── modules
│   ├── b64.c
│   ├── b64.h
│   ├── bbf-vomci
│   │   ├── bbf-vomci.c
│   │   ├── bbf-vomci.h
│   │   └── CMakeLists.txt
│   ├── bbf-xpon-dummy
│   │   ├── bbf-xpon.c
│   │   ├── bbf-xpon.h
│   │   └── CMakeLists.txt
│   ├── bcmolt_netconf_constants.h
│   ├── bcmolt_netconf_module_init.c
│   ├── bcmolt_netconf_module_init.h
│   ├── bcmolt_netconf_module_utils.c
│   ├── bcmolt_netconf_module_utils.h
│   ├── bcmolt_netconf_notifications.c
│   ├── bcmolt_netconf_notifications.h
│   └── CMakeLists.txt
└── start_netconf_server.sh

File bbf-vomci.c implements WT-451 bbf-polt-vomci.yang YANG model. Other files listed above are common utilities and the "main" program.

File bbf-xpon-dummy/bbf-xpon.c is a dummy TR-385 implementation that registers for ietf-interfaces changes and OKs all changes. This module is initialized if bcm_netconf_server is started with command line option "-dummy_tr385". This dummy module is required if there is no "real" TR-385 netconf server registered with the same sysrepo2. Otherwise, all ietf-interface changes will remain in "pending" datastore and some bbf-polt-vomci notifications will fail because of references to "non-existing" interfaces.

gRPC client/server

tr451_vomci_polt
├── bcm_tr451_polt_cli.cc                  <--- CLI commands
├── bcm_tr451_polt_client.cc               <--- gRPC client implementation
├── bcm_tr451_polt_common.cc               <--- Common client & server code: filters, ONU add/delete, common connection handling
├── bcm_tr451_polt.h                       <--- External C interface, for NETCONF server integration
├── bcm_tr451_polt_internal.h              <--- Class definitions, internal functions
├── bcm_tr451_polt_server.cc               <--- gRPC server imnplementation
├── CMakeLists.txt
├── grpc_cli_examples
│   └── examples.txt
├── message_definition
... .proto files
│   ├── tr451_vomci_function_sbi_message.proto
│   └── tr451_vomci_function_sbi_service.proto
├── polt_daemon
│   ├── bcm_tr451_polt_main.c              <--- "alternative" main program for gRPC-only application, without NETCONF/YANG part
│   ├── CMakeLists.txt
│   └── start_tr451_polt.sh                <--- startup shell script
├── README
└── tr451_polt_vendor                      <--- vendor sub-layer
    ├── CMakeLists.txt
    ├── sim
    │   ├── CMakeLists.txt
    │   ├── sim_tr451_polt_vendor.cc          <--- simulation "vendor" implementation
    │   ├── sim_tr451_polt_vendor_cli.cc      <--- simulation "vendor" CLI commands
    │   ├── sim_tr451_polt_vendor_internal.h
    │   └── tr451_polt_vendor_specific.h      <--- simulation "vendor"-specific interfaces
    ├── tr451_polt_for_vendor.h            <--- Helper functions that "vendor" implementation is allowed to use
    └── tr451_polt_vendor.h                <--- Functions and interfaces that "vendor" sub-layer must implement

Although NETCONF/YANG server is implemented in C, gRPC client/server is implemented

Vendor interface

Internally pOLT package has a vendor sub-layer for interacting with ONU via vendor-specific OLT interface. Vendor interface is defined in the following header files:

tr451_polt_vendor/tr451_polt_vendor.h - interfaces that vendor sub-layer must implement
tr451_polt_vendor/tr451_polt_for_vendor.h - common interfaces that vendor sub-layer can use In addition each vendor can define vendor-specific interfaces in file tr451_polt_vendor//tr451_polt_vendor_specific.h.

The only vendor interface released as Open Source is "sim" which stands for simulation.

Class hierarchy

See class-diagram.uml, class-diagram.png in tr451_vomci_polt directory

TS32/bbf-wt451-polt-sim