# ISP Backbone Lab — A Senior Network Engineer's Course

> **Instructor**: Garvis (your friendly neighborhood Sr. Network Engineer)
> **Platform**: Cisco Modeling Labs (CML) — 32GB RAM budget
> **Student**: Jordan
> **Goal**: Build and understand a realistic ISP backbone from the ground up, then attack it.

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## Table of Contents — Modules

| # | Module | Topic |
|---|--------|-------|
| 1 | [Module 1: The Underlay — IS-IS](modules/01-isis.md) | Why every ISP uses IS-IS, Level 2-only design, NET addressing |
| 2 | [Module 2: MPLS — Labeling the Backbone](modules/02-mpls.md) | Label switching, LDP, Penultimate Hop Popping |
| 3 | [Module 3: iBGP — The Brain of the ISP](modules/03-ibgp.md) | Route Reflectors, full-mesh problem, loopback peering |
| 4 | [Module 4: L3VPN — Customer Isolation](modules/04-l3vpn.md) | VRFs, RD vs RT, customer isolation across the MPLS core |
| 5 | [Module 5: eBGP — Peering with the World](modules/05-ebgp.md) | IXP peering, BGP best path selection (The Big 9), route filtering |
| 6 | [Module 6: Segment Routing](modules/06-segment-routing.md) | LDP to SR migration, Prefix SIDs, why SR is the future |
| 7 | [Module 7: Traffic Engineering](modules/07-traffic-engineering.md) | SR-TE policies, SID stacks, Flex-Algo |
| 8 | [Module 8: Attack & Defense Labs](modules/08-attack-defense.md) | BGP hijacking, IS-IS poisoning, MPLS label manipulation, CoPP |

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## The Topology

A **two-AS ISP backbone** (AS 65000 and AS 65100) with customer sites, a peering exchange, and an attacker segment.

See the [topology diagrams](diagrams/) for visual references.

## Build Order

### Phase 1: Foundation (Weekend 1)
- Module 1: IS-IS on all P and PE routers
- Verify: All loopbacks reachable

### Phase 2: MPLS Core (Weekend 2)
- Module 2: MPLS/LDP on all core links
- Module 3: iBGP with Route Reflector

### Phase 3: Services (Weekend 3)
- Module 4: VRFs and L3VPN
- Module 5: eBGP peering at the IXP

### Phase 4: Modern SP (Weekend 4)
- Module 6: Migrate LDP to Segment Routing
- Module 7: SR-TE policies

### Phase 5: Break Things (Weekend 5+)
- Module 8: Attack and defense scenarios

## Quick Reference Commands

| What You Want | Command |
|--------------|---------|
| IS-IS neighbors | `show isis neighbors` |
| MPLS labels | `show mpls forwarding-table` |
| BGP summary | `show bgp summary` |
| VRF routes | `show ip route vrf CUST_A` |
| SR SIDs | `show isis segment-routing prefix-sid-map` |
