Multi-area-OSPF-lisp

Multi-Area OSPF backbone integrated with LISP overlay to simulate scalable enterprise WAN design.

📌 Project Overview

This lab demonstrates an enterprise-style routed network using:

• Multi-Area OSPF Design
• ABR implementation
• Inter-Area Route Propagation
• LISP (Locator/ID Separation Protocol)
• ITR / ETR configuration
• EID-to-RLOC mapping
• Control-plane + Data-plane validation

The objective is to show how hierarchical OSPF design integrates with LISP for scalable routing and endpoint mobility.

---

🗺️ Network Diagram

---

🏗 Topology Overview

• CORE-01 → Area 0 (Backbone)
• CORE-02 → ABR (Area 0 / Area 2)
• EDGE-01 → Area 1
• EDGE-02 → Area 2
• LISP deployed on Edge routers
• Map-Server / Map-Resolver: 1.1.1.1

LISP is deployed at the edge routers to separate endpoint identity from routing location.

---

🧠 OSPF Design Explanation

Why Multi-Area OSPF?

Single-area OSPF does not scale well in large networks due to:

• Large LSDB size
• High SPF recalculation load
• Slower convergence

Multi-area OSPF solves this by:

• Reducing LSDB scope
• Limiting LSA flooding
• Reducing CPU usage
• Creating hierarchical routing

---

🌐 OSPF Design

Device	OSPF Area
CORE-01	Area 0
CORE-02	Area 0/2
EDGE-01	Area 1
EDGE-02	Area 2

• Multi-area hierarchy
• Inter-area route learning (O IA routes)
• Proper ABR implementation

---

🔍 Verification

OSPF Verification

1. Neighbour Adjacency

Expected result:

• FULL adjacency
• DR/BDR election where applicable

Command:

show ip ospf neighbor

Output:

Neighbor ID     Pri   State           Dead Time   Address         Interface
1.1.1.1           1   FULL/BDR        00:00:38    10.0.0.1        TenGigabitEthernet0/0/4
10.10.10.2        1   FULL/BDR        00:00:34    10.2.2.2        GigabitEthernet0/0/0

• Neighbor ID
• State FULL
• Correct interface
• Correct DR election

2. Routing Table Validation

Expected routes:

• O → Intra-area
• O IA → Inter-area (via ABR)

Command:

show ip route ospf

Output:

      2.0.0.0/32 is subnetted, 1 subnets
O        2.2.2.2 [110/2] via 10.0.0.2, 01:01:15, TenGigabitEthernet0/0/4
      10.0.0.0/8 is variably subnetted, 7 subnets, 2 masks
O IA     10.2.2.0/30 [110/2] via 10.0.0.2, 01:01:15, TenGigabitEthernet0/0/4
O        10.10.10.1/32 [110/2] via 10.1.1.2, 01:01:14, GigabitEthernet0/0/0
O IA     10.10.10.2/32 [110/3] via 10.0.0.2, 00:53:43, TenGigabitEthernet0/0/4

✔ Inter-area routes successfully learned
✔ ABR functioning properly

---

🌍 LISP Design

What is LISP?

LISP (Locator/ID Separation Protocol) separates:

• EID (Endpoint Identifier) → Who you are
• RLOC (Routing Locator) → Where you are

Traditional IP routing ties identity and location together.
LISP separates them to improve scalability and mobility.

---

🔹 LISP Components Used

• ITR → Ingress Tunnel Router
• ETR → Egress Tunnel Router
• Map-Server → 1.1.1.1
• Map-Resolver → 1.1.1.1
• Loopback interface → RLOC

---

🔧 LISP Configuration Concept

Example from EDGE-02:

router lisp
 database-mapping 192.168.2.0/24 10.10.10.2 priority 1 weight 100
 ipv4 itr map-resolver 1.1.1.1
 ipv4 itr
 ipv4 etr map-server 1.1.1.1 key <authentication-key>
 ipv4 etr

---

Verification

Check LISP status

Command:

show lisp session

Output (Edge-02):

Sessions for VRF default, total: 1, established: 1
Peer                           State      Up/Down        In/Out    Users
1.1.1.1:4342                   Up         00:57:13        7/5      4

Command:

show lisp site

Output (CORE-01):

LISP Site Registration Information
* = Some locators are down or unreachable
# = Some registrations are sourced by reliable transport

Site Name      Last      Up     Who Last             Inst     EID Prefix
               Register         Registered           ID       
BRANCHES       00:58:42  yes#   10.10.10.1:13549     0        192.168.1.0/24
               00:52:41  yes#   10.10.10.2:61384     0        192.168.2.0/24

Command:

show lisp map-cache

Output (Edge-01):

LISP IPv4 Mapping Cache for EID-table default (IID 0), 7 entries

0.0.0.0/0, uptime: 00:00:37, expires: 00:00:22, via static-send-map-request
  Negative cache entry, action: send-map-request
0.0.0.0/1, uptime: 00:35:42, expires: 00:09:02, via map-reply, forward-native
  Negative cache entry, action: forward-native
128.0.0.0/2, uptime: 00:35:41, expires: 00:09:02, via map-reply, forward-native
  Negative cache entry, action: forward-native
192.168.2.0/24, uptime: 00:35:36, expires: 23:24:24, via map-reply, complete
  Locator     Uptime    State  Pri/Wgt     Encap-IID
  10.10.10.2  00:35:36  up       1/100       -
192.168.8.0/21, uptime: 00:35:28, expires: 00:09:15, via map-reply, forward-native
  Negative cache entry, action: forward-native
200.0.0.0/5, uptime: 00:35:41, expires: 00:09:03, via map-reply, forward-native
  Negative cache entry, action: forward-native
208.0.0.0/4, uptime: 00:32:20, expires: 00:12:23, via map-reply, forward-native
  Negative cache entry, action: forward-native

Expected:

✔ EID registered
✔ Map-cache entries populated
✔ RLOC reachable
✔ Control-plane established

---

📊 Control Plane vs Data Plane

Plane	Function
Control Plane	Map-Request / Map-Reply
Data Plane	Encapsulated LISP traffic

Control-plane builds mapping database.
Data-plane forwards encapsulated packets.

---

🚀 Key Learning Outcomes

• Designing hierarchical OSPF networks
• Implementing ABR functionality
• Understanding O IA route types
• Deploying LISP ITR/ETR
• Mapping EID to RLOC
• Verifying LISP control-plane
• Integrating OSPF + LISP

---