**Observed**: Route advertisement from Tier1 (212.36.0.0/22) was already present, causing an error; ping command issues due to Unicode characters; EveLink’s route (31.41.0.0/24) was preconfigured; route propagation policies required AS path prepending.  
**Decided**: Confirm Tier1’s route, fix ping syntax, propagate customer routes to Tier1, prepend AS path for EveLink, and coordinate route updates via messages.  
**Why**: Adhere to route policies (customer precedence, peer isolation), ensure valid commands for connectivity, and enforce IRR/AltDB compliance while optimizing path selection.
**Experiment Report**  

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### **1. Actions Taken**  
1. **Tier1 Route Installation**:  
   - Added `212.36.0.0/22` via `TransitAS-eth0` (gateway `10.3.0.1`).  
   - Confirmed route existence after an initial "File exists" error using `ip route show`.  
   - Sent confirmation to Tier1 that the route was installed.  

2. **Customer Route Handling (ISP)**:  
   - Configured routes for ISP’s `85.12.64.0/22` (via `TransitAS-eth1`) and TINYINC’s `45.32.0.0/24` (via ISP’s transit).  
   - Ran `ping -c 3 -I 91.108.0.1 85.12.64.1` to verify reachability, fixing Unicode formatting errors in the command.  

3. **Customer Route Handling (EveLink)**:  
   - Added EveLink’s `31.41.0.0/24` via `TransitAS-eth2` (gateway `10.3.2.2`).  
   - Notified Tier1 of EveLink’s route with AS path prepending (`[65002 65588]`).  
   - Verified reachability via `ping -c 3 -I 91.108.0.1 31.41.0.1`, correcting formatting errors.  

4. **Policy Compliance**:  
   - Ensured customer routes (`ISP`, `EveLink`) were preferred over peer routes.  
   - Avoided advertising peer (`Tier1`)-learned routes to other peers.  

5. **Finalization**:  
   - Ran `report_done` after confirming all routes were installed and tested successfully.  

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### **2. Justifications**  
- **Tier1 Route**: Installed per their advertisement and Gao-Rexford policy (peering agreement). The route’s validity was confirmed via the IRR (RIPE-verified `AS-TIER1`).  
- **ISP Routes**: TINYINC’s `45.32.0.0/24` was accepted as a customer-of-customer route, propagated via ISP. The `85.12.64.0/22` route was validated against RIPE records.  
- **EveLink Route**: Added after receiving their explicit advertisement (`AS-EVELINK` in AltDB). AS path prepending to Tier1 ensured proper preference for customer routes.  
- **Ping Commands**: Used loopback source (`91.108.0.1`) to avoid routing issues with link-local addresses. Unicode errors were fixed to ensure commands executed correctly.  
- **Route Prioritization**: Customer routes were preferred over peers to comply with policy (customer > peer > transit). Peer routes were not advertised further to uphold peering terms.  

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### **3. Discoveries**  
- **Network Topology**:  
  - TransitAS acts as a regional provider connected to Tier1 (peer), ISP, and EveLink (customers).  
  - ISP originates `85.12.64.0/22` and carries TINYINC’s `45.32.0.0/24` (via transit).  
  - EveLink originates `31.41.0.0/24`, validated via AltDB.  
- **Routing Behavior**:  
  - All routes were reachable via configured paths.  
  - ICMP tests confirmed end-to-end connectivity from loopback addresses.  
- **Policy Adherence**:  
  - Gao-Rexford rules were enforced: no invalid routes (e.g., infrastructure subnets) were propagated.  
  - AS path prepending ensured proper routing precedence for customer routes.  

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### **4. Coordination with Other Agents**  
- **Tier1**:  
  - Acknowledged their route advertisement and confirmed installation.  
  - Notified them of new customer routes (EveLink’s `31.41.0.0/24`) to maintain bidirectional paths.  
- **EveLink**:  
  - Requested their route advertisement explicitly after detecting missing connectivity.  
  - Confirmed their route was installed and propagated to Tier1.  
- **ISP**:  
  - Implicit coordination via route propagation over the transit link. No direct messages were required as their routes were inferred from traffic and AltDB/IRR records.  

---

### **Conclusion**  
The experiment achieved full network convergence with policy-compliant routing. All customer and peer routes were validated, installed, and tested. Coordination with peers/customers via explicit messages ensured mutual route awareness and compliance with peering/transit agreements. Formatting corrections and policy adherence were critical to resolving errors and maintaining stable connectivity.