OLT and ONT Configuration

Optical Line Terminal and Optical Network Terminal configuration for subscriber access

OLT and ONT Configuration

The Nokia BNG Lab uses a Nokia 7250 IXR-EC router as the Optical Line Terminal (OLT) to aggregate subscriber traffic from Optical Network Terminals (ONTs). This page covers the configuration of both the OLT and the ONT devices.

OLT Configuration

Hardware Overview

Device Type: Nokia 7250 IXR-EC

Management IP: 10.77.1.5

Hardware Components:

• CPM-IXR-EC control module
• M4-1G-TX+20-1G-SFP+6-10G-SFP+ MDA

Access Ports:

• SSH: Port 56678
• gRPC: Port 56671
• NETCONF: Port 56672

System Configuration

/configure system name "OLT-NOKIA"
/configure system time zone standard name est

Management Interfaces

# gRPC Configuration
/configure system grpc admin-state enable
/configure system grpc allow-unsecure-connection
/configure system grpc gnmi auto-config-save true

# NETCONF Configuration
/configure system management-interface netconf listen admin-state enable
/configure system management-interface configuration-save configuration-backups 5
/configure system management-interface netconf auto-config-save true

# SNMP Configuration
/configure system management-interface snmp packet-size 9216
/configure system management-interface snmp streaming admin-state enable
/configure system security snmp community "public" access-permissions r
/configure system security snmp community "public" version v2c

OLT Port Configuration

The OLT has three critical port connections:

Uplink to Switch

/configure port 1/1/1 admin-state enable
/configure port 1/1/1 ethernet mode hybrid
/configure port 1/1/1 ethernet encap-type qinq

The uplink port uses QinQ (802.1ad) encapsulation to support VLAN stacking, allowing multiple service VLANs per subscriber.

ONT1 Connection (IPoE)

/configure port 1/1/2 admin-state enable
/configure port 1/1/2 ethernet mode access
/configure port 1/1/2 ethernet encap-type dot1q

ONT2 Connection (PPPoE)

/configure port 1/1/3 admin-state enable
/configure port 1/1/3 ethernet mode access
/configure port 1/1/3 ethernet encap-type dot1q

ONT-facing ports use access mode with dot1q (single VLAN tag) encapsulation. The OLT adds the outer VLAN tag for QinQ toward the BNG.

VPLS Services

The OLT uses Virtual Private LAN Service (VPLS) to aggregate subscriber traffic for each BNG:

VPLS for BNG1 Subscribers

/configure service vpls "bng1-agg" admin-state enable
/configure service vpls "bng1-agg" service-id 50
/configure service vpls "bng1-agg" customer "1"
/configure service vpls "bng1-agg" stp admin-state disable

# Uplink SAP (to Switch, toward BNG1)
/configure service vpls "bng1-agg" sap 1/1/1:50.150 admin-state enable

# Downlink SAP (to ONT1)
/configure service vpls "bng1-agg" sap 1/1/2:150 admin-state enable

VLAN Tag Explanation

Uplink SAP (1/1/1:50.150):

• Outer VLAN (S-VLAN): 50 - Identifies BNG1 service
• Inner VLAN (C-VLAN): 150 - Subscriber VLAN

Downlink SAP (1/1/2:150):

• Single VLAN tag: 150 - Subscriber VLAN

The OLT performs VLAN translation, adding/removing the outer tag (50) as traffic flows between the ONT and the BNG.

VPLS for BNG2 Subscribers

/configure service vpls "bng2-agg" admin-state enable
/configure service vpls "bng2-agg" service-id 60
/configure service vpls "bng2-agg" customer "1"
/configure service vpls "bng2-agg" stp admin-state disable

# Uplink SAP (to Switch, toward BNG2)
/configure service vpls "bng2-agg" sap 1/1/1:60.150 admin-state enable

# Downlink SAP (to ONT2)
/configure service vpls "bng2-agg" sap 1/1/3:150 admin-state enable

Spanning Tree Protocol (STP) is disabled on these VPLS instances. Ensure there are no Layer 2 loops in your network topology.

Network Topology

┌─────────┐    ┌─────────┐
│  BNG1   │    │  BNG2   │
└────┬────┘    └────┬────┘
     │              │
     └──────┬───────┘
            │
      ┌─────┴─────┐
      │  Switch   │
      └─────┬─────┘
            │ Port 1/1/1 (QinQ)
      ┌─────┴─────┐
      │    OLT    │
      └─┬───────┬─┘
        │       │
   Port │       │ Port
   1/1/2│       │ 1/1/3
    ┌───┴──┐ ┌──┴───┐
    │ ONT1 │ │ ONT2 │
    │(IPoE)│ │(PPPoE│
    └──────┘ └──────┘

ONT Configuration

The ONT devices are Linux containers that simulate optical network terminals. They are configured via environment variables in the lab.yml file.

ONT1 - IPoE Configuration

lab.yml

ont1:
  kind: linux
  mgmt-ipv4: 10.77.1.6
  image: ghcr.io/abelperezr/ont-ds:0.2
  env:
    CONNECTION_TYPE: ipoe
    VLAN_ID: "150"
    IFPHY: "eth1"
    IFLAN: "eth2"
    MAC_ADDRESS: "00:D0:F6:01:01:01"
    USER_PASSWORD: "test"
  ports:
    - 56673:22
    - 8081:8080

ONT1 Details:

• Connection Type: IPoE (DHCP-based)
• VLAN ID: 150
• MAC Address: 00:D0:F6:01:01:01
• Physical Interface: eth1 (to OLT port 1/1/2)
• LAN Interface: eth2 (to PC1)
• SSH Access: Port 56673
• Web Dashboard: Port 8081
• Connected to: BNG1 (via OLT VPLS service-id 50)

ONT2 - PPPoE Configuration

lab.yml

ont2:
  kind: linux
  mgmt-ipv4: 10.77.1.7
  image: ghcr.io/abelperezr/ont-ds:0.2
  env:
    CONNECTION_TYPE: pppoe
    PPP_USER: "[e-mail]"
    PPP_PASS: "testlab123"
    VLAN_ID: "150"
    IFPHY: "eth1"
    IFLAN: "eth2"
    MAC_ADDRESS: "00:D0:F6:01:01:02"
    USER_PASSWORD: "test"
  ports:
    - 56674:22
    - 8082:8080

ONT2 Details:

• Connection Type: PPPoE (username/password authentication)
• PPPoE Credentials:
  • Username: [e-mail]
  • Password: testlab123
• VLAN ID: 150
• MAC Address: 00:D0:F6:01:01:02
• Physical Interface: eth1 (to OLT port 1/1/3)
• LAN Interface: eth2
• SSH Access: Port 56674
• Web Dashboard: Port 8082
• Connected to: BNG2 (via OLT VPLS service-id 60)

VLAN Configuration Summary

VLAN 150

Subscriber VLAN (C-VLAN)

Used by all ONT devices for subscriber traffic.

• ONT1 tags traffic with VLAN 150 → OLT port 1/1/2
• ONT2 tags traffic with VLAN 150 → OLT port 1/1/3

VLAN 50

BNG1 Service VLAN (S-VLAN)

Outer VLAN tag added by OLT for BNG1-bound traffic.

• QinQ format: 50.150
• Aggregates ONT1 traffic
• Delivered to BNG1 via Switch

VLAN 60

BNG2 Service VLAN (S-VLAN)

Outer VLAN tag added by OLT for BNG2-bound traffic.

• QinQ format: 60.150
• Aggregates ONT2 traffic
• Delivered to BNG2 via Switch

Connection Type Comparison

IPoE

IP over Ethernet (IPoE)

Pros:

• Simpler configuration
• No PPP overhead
• Faster session establishment
• Native IP addressing

Authentication:

• Based on MAC address
• DHCP Option 82 (Circuit ID/Remote ID)
• RADIUS attributes

Use Case:

• ONT1 demonstrates IPoE with DHCP
• Suitable for residential subscribers

PPPoE

PPP over Ethernet (PPPoE)

Pros:

• User credentials authentication
• Per-session accounting
• Better control and troubleshooting
• Standards-based (RFC 2516)

Authentication:

• Username and password
• PAP or CHAP
• RADIUS Access-Request

Use Case:

• ONT2 demonstrates PPPoE
• Common in DSL/fiber deployments

Interface Mapping

Device	Physical Port	Encapsulation	VLAN(s)	Connected To
OLT	1/1/1	QinQ	50.150, 60.150	Switch
OLT	1/1/2	dot1q	150	ONT1
OLT	1/1/3	dot1q	150	ONT2
ONT1	eth1	dot1q	150	OLT 1/1/2
ONT2	eth1	dot1q	150	OLT 1/1/3

Traffic Flow

IPoE Session (ONT1 → BNG1)

1. ONT1 sends DHCP Discover with VLAN 150
2. OLT receives on port 1/1/2, adds outer VLAN 50 → 50.150
3. Switch forwards QinQ frame to BNG1
4. BNG1 capture SAP triggers on DHCP packet
5. BNG1 performs RADIUS authentication (MAC-based)
6. BNG1 responds with DHCP Offer
7. ONT1 completes DHCP handshake and receives IP address

PPPoE Session (ONT2 → BNG2)

1. ONT2 sends PPPoE PADI (Discovery) with VLAN 150
2. OLT receives on port 1/1/3, adds outer VLAN 60 → 60.150
3. Switch forwards QinQ frame to BNG2
4. BNG2 capture SAP triggers on PPPoE packet
5. BNG2 responds with PPPoE PADO (Offer)
6. ONT2 sends PADR (Request)
7. BNG2 performs RADIUS authentication (username/password)
8. BNG2 responds with PADS (Session confirmation)
9. PPP negotiation (LCP, IPCP, IPv6CP)
10. ONT2 receives IP address and establishes session

Both connection types require successful RADIUS authentication. Ensure the RADIUS server is running and accessible at 10.77.1.10.

Verification Commands

OLT Status

# SSH into OLT
ssh admin@10.77.1.5 -p 56678

# Check VPLS services
show service service-using
show service id 50 base
show service id 60 base

# Check SAP status
show service sap 1/1/2:150
show service sap 1/1/3:150

# Check port status
show port 1/1/1
show port 1/1/2 detail
show port 1/1/3 detail

ONT Status

ONT1 (IPoE)

# SSH into ONT1
ssh root@10.77.1.6 -p 56673

# Check VLAN interface
ip link show eth1.150

# Check DHCP lease
cat /var/lib/dhcp/dhclient.leases

# Test connectivity
ping -c 4 8.8.8.8

Configuration Files

The complete configuration files are located at:

• OLT: configs/olt/olt.txt
• Lab Topology: lab.yml (ONT definitions in nodes section)

Related Topics

• BNG Router Configuration
• RADIUS Server Configuration
• Network Services Configuration