SRv6 Lab: Access, Aggregation, and Core IP Network Simulation

This is a comprehensive lab simulating an access, aggregation, and core IP network using SRv6 (Segment Routing over IPv6) technology. The lab demonstrates L2 service interworking between an SRv6 domain in access ring 2 and a legacy RSVP domain in access ring 1, showcasing modern network evolution and service continuity.

A. Network Architecture Overview

The lab consists of three main network layers:

1. Access Ring 1: Legacy RSVP Domain

• R01-IXR (IXR-R6): Access router with 10G/100G interfaces
• R02-IXR (IXR-e2): Access access router
• R03-IXR (IXR-R6): Access router with 10G/100G interfaces
• R04-IXR (IXR-R6): Access with 10G/100G interfaces

2. Core Network: SRv6 & RSVP Domain

• R05-SR to R12-SR (SR-1): Core routers forming the backbone with both SRv6 and RSVP enabled
• R05-SR & R06-SR: ASBR (Autonomous System Border Routers) connecting RSVP to SRv6
• R11-SR & R12-SR: ASBR connecting SRv6 to SRv6 access ring

3. Access Ring 2: SRv6 Domain

• R13-IXR (IXR-R6d): SRv6 Access router with 100G QSFP28
• R14-IXR (IXR-e2): SRv6 Access router
• R15-IXR (IXR-R6d): SRv6 Access router with 100G QSFP28
• R16-IXR (IXR-e2): SRv6 Access router

Key Features

• Multi-Domain Interworking: Seamless L2 service delivery between RSVP and SRv6 domains
• Modern Network Evolution: Smooth migration from legacy RSVP to modern SRv6
• Comprehensive Testing: Multiple test endpoints for service validation
• Telemetry Integration: Full observability with Prometheus, Grafana, and gNMI
• Containerized Deployment: Easy deployment using Containerlab using Nokia SR-SIM

B. Lab Overview

Service Validation

• L2 Epipe services between RSVP and SRv6 domains
• End-to-end connectivity verification
• Performance metrics collection

High-Level Topology

Technology Stack

• Containerlab: Network topology orchestration (0.69.3 or higher)
• Nokia SROS: Network operating system (25.7.R1 for SR-SIM support. If only vSIM is available, use 24.10.R1 or newer)
• SRv6: Segment Routing over IPv6 for modern packet forwarding
• RSVP-TE: Legacy traffic engineering protocol
• EVPN: multi-instance service layer for RSVP and SRv6 interworking
• PW-switching: PW switching for legacy deployment using a PW per domain stitched at the ASBR
• gNMI: Network configuration and telemetry
• Prometheus + Grafana: Monitoring and visualization
• UPA: prefix summarization for SRv6 locators including Unreachable Prefix Announcement (UPA)

C. Getting Started

Prerequisites

• Docker and Containerlab installed
• Nokia SROS license files (see license section in topology file)
• Sufficient system resources for 16+ network nodes

Deployment

1. Clone the repository:

git clone https://github.com/giancarlo3g/srv6_lab.git
cd srv6_lab

2. Deploy the topology:

containerlab deploy

3. Verify deployment:

containerlab inspect

Management Access

All nodes are accessible via SSH on the following ports:

• RSVP Access Ring: 50101-50401 (R01-R04)
• Core SRv6: 50501-51201 (R05-R12)
• SRv6 Access Ring: 51301-51601 (R13-R16)
• Test Endpoints: 172.20.20.120-128
• Management Network: 172.20.20.0/24

Configuration

• Node Configs: Located in ./config/ directory
• Telemetry Configs: Located in ./tele-config/ directory
• Topology File: topo.clab.yml (main deployment file)

Monitoring & Telemetry

The lab includes comprehensive monitoring capabilities:

• Prometheus: Metrics collection on port 9090
• Grafana: Visualization dashboard on port 3000
• Consul: Service discovery on port 8500
• gNMI: Network telemetry streaming

Useful SRv6 commands

For classic SID

/show router isis 1 segment-routing-v6 locator
/show router segment-routing-v6 local-sid
/show router isis segment-routing-v6 locator

For micro-SID (uSID or Next-CSID)

/show router segment-routing-v6 micro-segment-locator 
/show router segment-routing-v6 micro-segment-local-sid
/show router isis 1 segment-routing-v6 micro-segment-locator 

/show fwd-path-ext fpe 1
/show router route-table ipv6 2001:ac8:0:b::/64 
/show router tunnel-table ipv6 2001:ac8:0:b::/64
/show router tunnel-table ipv6 2001:ac8:0:b::/64 alternative 
/show router fib 1 ipv6 ip-prefix-prefix-length 2001:ac8:0:b::/64
/show router bgp routes 172.31.3.0/24 vpn-ipv4 detail

C. Testing & Validation

Test Endpoints

• tester1-tester5: RSVP domain connectivity testing
• tester11, tester13, tester14, tester16: SRv6 domain connectivity testing

Detailed Port-Level Topology

Service Interworking

The lab demonstrates L2 service continuity between:

• Legacy RSVP domain (Access Ring 1)
• Modern SRv6 domain (Access Ring 2)

This showcases how service providers can evolve their networks while maintaining existing customer services.

1. Intra-domain RSVP-based ELINE:

• epipe (T-LDP) R2-R3_2000
• Connectivity test between tester1 (IP 192.168.0.1, VLAN 10) and tester14 (IP 192.168.0.14, VLAN 10)

2. Inter-domain RSVP-based ELINE with PW-switching

• epipe (T-LDP) R1-R14_3000
• RSVP-based LSP/SDP per domain stitched at ASBR
• Includes PW-redundancy from R01 to both ASBR R05/R06
• Connectivity test between tester1 (IP 192.168.0.1, VLAN 10) and tester14 (IP 192.168.0.14, VLAN 10)

3. Intra-domain SRv6-based ELINE

• epipe (BGP-EVPN) R13-R16_VPWS-SRv6
• Summarization on ASBR nodes R11 and R12
• Connectivity test between tester13 (IP 10.13.16.13, VLAN 1316) and tester16 (IP 10.13.16.16, VLAN 1316)

4. Inter-domain SRv6-based ELINE

• epipe (BGP-EVPN) R05-R16_VPWS-SRv6
• Summarization on ASBR nodes R11 and R12
• Connectivity between tester5 (IP 10.5.16.5, VLAN 516) and tester16 (IP 10.5.16.16, VLAN 516)

5. Inter-domain RSVP to SRv6 ELINE

• epipe R04-R13_VPWS-SRv6
• RSVP-based LSP/SDP with T-LDP epipe on access ring 1 from R04 to both ASBR nodes R05/R06
• SRv6 from ASBR nodes R05 and R06 to R13
• Connecitivy between tester4 (IP 10.4.13.4, VLAN 413) and tester13 (IP 10.4.13.13, VLAN 413)

Configuration

1. 7750 SR
2. 7250 IXR
3. Summarization & UPA

Project Structure

srv6_lab/
├── topo.clab.yml               # Main topology file
├── topology/                   # Network diagrams
│   ├── Topology.png            # High-level topology
│   └── detailed_topology.png   # Port-level details
├── config/                     # Node configurations
├── tele-config/                # Telemetry configurations
│   ├── gnmic.yaml              # gNMIc configuration
│   ├── grafana/                # Grafana configuration
│   └── prometheus/             # Prometheus configuration
├── commands/                   # Command reference files
├── srv6_7250.md                # 7250 IXR configuration guide
├── srv6_7750.md                # 7750 SR configuration guide
├── upa.md                      # UPA and prefix summarization configuration guide
├── save_config.sh              # Configuration backup script
├── .gitignore                  # Git ignore file
└── README.md                   # This file

Contributing

This lab is designed for educational and testing purposes. Feel free to modify configurations and experiment with different SRv6 scenarios.

Additional Resources

• Containerlab Documentation
• Nokia SROS Documentation
• Nokia SR-SIM
• SRv6 Network Programming
• BGP services over SRv6
• Compressed SRv6

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Note: Ensure you have valid Nokia SROS licenses before deploying this lab. The topology file references license files that must be present in the parent directory ../srv6_lab/.