**6. Lessons**

376 Earthquake Research and Analysis – Statistical Studies, Observations and Planning

Figure 19 shows the traffic load for each source AS. Although the total traffic is about 0.4 Gbps, the real KR traffic was about 0.2 Gbps. 0.1 Gbps is occupied by CERNET traffic and

In spite of the recovery steps, a few sites that had only single-link connections to the Internet could not directly reach the R&E networks. Therefore, after the fiber was fixed, a few singlelink sites had the connections via Internet commodity service. To fix this problem, the operators had to change the port configuration at switches that were able to provide high

Two days after the earthquake, the link between KR and SG was restored and SG started making routing announcements to TEIN2 members (ID, SG, TH, MY). However, the link between SG and KR was not the original fiber, and its RTT increased greatly because a detour route was assigned. Similarly, the direct link between PH and JP was replaced with a detour route with a long RTT. When an online demonstration was being prepared for the 2007 APAN meeting held in PH between January 22nd and 26th 2007, the restored JP-PH link had a very long RTT because it went through mainland China, as shown in Fig. 20.

During the 23rd APAN meeting demonstration, the Prince of Wales Hospital at the Chinese University of Hong Kong (CUHK) was expected to join. However, its IP prefix was announced only by CSTNET. Thus, it was only reachable over a commodity Internet link with a small bandwidth. To solve this problem, APAN Tokyo XP changed the port configuration of fibers. That is, the CSTNET fiber for accessing APAN Tokyo XP was

the rest by TEIN2.

**5.3 Port reconfiguration** 

performance connections.

Fig. 20. JP-PH detour route circuit

From the process of recovering from network failures across several ISP's in Asia Pacific R&E networks, we encountered several network management challenges especially regarding fault management. In this subsection, we describe the lessons learned during the recovery operations.
