## **Objective**

Implementation of a **centralized, consistent NTP structure** for all devices in HQ1, HQ2, BR1, and BR2 to ensure:

- **IR1 and IR2** synchronize directly with **ISP1**
- all other devices use **IR1 and IR2 as internal NTP servers**
- NTP communication uses **Loopback addresses**
- task requirements are met exactly

---

## **1. NTP Design**

- External time source:
    - ISP1 peering IPs:
        - 192.0.2.101 (for IR1)
        - 192.0.2.201 (for IR2)
- Internal NTP servers:
    - IR1 → 10.10.0.1 (Loopback1)
    - IR2 → 10.10.0.11 (Loopback1)
- NTP source interface:
    - Default: **Loopback1**
    - Exception: **AS1–AS4**, use **SVI VLAN 103**
- Hierarchical NTP design:
    - ISP1 → IR1 / IR2 → all remaining devices

---

## **2. NTP on IR1 and IR2 (Sync from ISP1)**

### **2.1 Configure NTP Server**

IR1:

```
ntp server 192.0.2.101
ntp source Loopback1
```

IR2:

```
ntp server 192.0.2.201
ntp source Loopback1
```

---

## **3. NTP on All Other Devices (HQ1, HQ2, BR1, BR2)**

### **3.1 Configure Internal NTP Servers**

```
ntp server 10.10.0.1
ntp server 10.10.0.11
ntp source Loopback1
```

---

## **4. Special Case: Access Switches AS1–AS4**

Requirement:

- NTP source must be **SVI VLAN 103**, not Loopback

```
ntp server 10.10.0.1
ntp server 10.10.0.11
ntp source Vlan103
```

---

## **5. Verification**

```
show ntp status
show ntp associations
```

Expected:

- IR1 / IR2 synchronized with ISP1
- All other devices synchronized with IR1 or IR2
- Source IP:
    - Loopback1 (routers, distribution switches)
    - Vlan103 (AS1–AS4)

---

## **Status**

- Central NTP hierarchy implemented correctly
- Unified time base across all sites
- Stable source addresses used for synchronization
- Task requirements fully fulfilled