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SoC Network Log

Note: We have stopped updating this page with new events. Network announcements and notices are now posted on our News page.

This is a log of unscheduled disruptions and problems affecting network service in SoC, including problems that are beyond the control of, and cannot be resolved by SoC network team. Note that disruptions and problems due to scheduled maintenance will not be listed here.

2006-06-22: Unscheduled Network Access Disruption

There was an unscheduled disruption to network access this afternoon from about 12:14pm. This was due to a burnt-out network core switch. Network access was mostly restored by 12:45, and full network service was back to normal by 1pm.

2005-09-20: Unscheduled Network Access Disruption

There was an unscheduled disruption to network access this evening from about 19:10 and progressively restored from about 19:50. Full network service was restored by 20:45.

2005-03-18: Unscheduled Network Access Disruption

There was an unscheduled disruption to network access this afternoon from about 3pm and restored by about 4pm. The CPUs on SoC core switches were overwhelmed by an unknown traffic storm, the cause of which is being investigated.

2004-04-13: Slow Internet Access

Internet access was slower and more lossy than normal yesterday. ComCen was notified and the problem has been rectified since about 2130 hrs yesterday. Loss and latency graphs are available.

2003-12-11: Slow Internet Access

Internet access was congested and slower than normal from 2003-12-10 1815 hrs to 2003-12-11 2100 hrs. This was due to an earthquake that cut SingAREN's main circuit to US, and subsequently all traffic was rerouted through a slower backup link.

2003-11-12: Unscheduled disruption to S14 Level 6 network

There was an unscheduled disruption to all network access at S14 Level 6 (both wired and wireless). This was most likely caused by an overheating problem in the wire centre serving that level, resulting in the failure of all switches at that location. The disruption started at about 18:40 and lasted until 23:00.

2003-04-15: Access to Internet/NUSNET is disrupted

Network access from SoC to Internet and NUSNET was disrupted from yesterday 2300hrs till today about 1020hrs due to a problem in Computer Centre's network. Computer Centre's staff have since rectified the problem. Ping-loss graph for this period is available here.

2003-01-25: Internet/NUSNET Disruption due to DDoS

Access to the Internet and certain parts of NUSNET was severely disrupted from approximately 13:30 to 19:30. This was due to a large scale distributed denial of service attack brought about by the MS SQL Slammer Worm. Ping-loss indicator for this period is available here.

SoC network was unaffected by the effect of the worm.

This worm exploits a (not new) vulnerability in Microsoft SQL Server. All users running Microsoft SQL Server are reminded to patch their servier. Patch information can be found at this CERT advisory.

2003-01-09: NUSNET Network Access Disruption

There was a network disruption in NUSNET (ComCen) network affecting access to the Internet and some parts of NUSNET. Network access within SoC was not affected. Ping-loss indicator for this period is available here.

2002-10-30: SoC Network Access Disruption

A major traffic storm severely impaired the performance of SoC core switches this morning from 10:30am. Normal network access was restored by 11:15am.

2002-08-22: Lossy Internet Access

Internet access was "slow and jerky" between 1900hrs on 2002-08-21 until 0000hrs on 2002-08-22 due to packet loss at ComCen network boundary with SingNet. Ping-loss indicator for this period is available here.

2002-04-30: Internet Access Down

Internet access is down from 1910hrs on 2002-04-30. CC has been notified of the problem and they are currently fixing it. Internet access has been restored at 1954hrs on 2002-04-30.

2002-02-18: SPnP Network Disruption

SPnP network access disruption (previously reported) at 0335hrs on 2002-02-17 has been restored at 1010hrs today 2002-02-18.

2002-02-17: Multiple Network Access Disruptions

There were three independent unscheduled network access disruptions in the last 16 hours. The first involved a likely routing anomaly within SoC network that lasted from 2155hrs to 2235hrs on 2002-02-16 (ping-loss indicator is available here). SoC network team is investigating the cause of the anomaly. The second problem was a loss of Internet connectivity beyond NUS ComCen from 2320hrs on 2002-02-16 to 0020hrs on 2002-02-17 (ping-loss indicator is available here).

SPnP network access was also disrupted at 0335hrs today (2002-02-17). This is still not rectified at this time (1420hrs).

2002-02-16: Intermittent Internet Access

Connectivity to Internet was disrupted on several occasions in the last 24 hrs. Ping-loss indicator is available here, and a slightly later snapshot here.

2002-02-15: Disruption in SPnP Network

There was an unscheduled disruption in SPnP Network access this morning from 0454hrs to 0944 hrs due to a routing problem in NUSNET core. ComCen has since rectified the problem.

2002-02-11: Internet Access Down

Connectivity to Internet was disrupted several times in the last 24hrs, the most recent ending at 2330hrs today. This is due to a network problem in ComCen. Ping-loss indicator for the period is available here.

2002-02-03: Intermittent Internet Access

Network access to the Internet has been intermittent with several periods of disruption in the last 24hrs. This is due to a network problem in ComCen. Ping-loss indicator for the period is available here.

2001-12-22: Internet Access Down

Network access to the Internet was down from 22 Dec 2001 0230hrs to 22 Dec 2001 1000hrs. This is due to the firewall in ComCen. They have been notified and the problem has since been rectified.

2001-12-12: Internet Access Performance Problems

Network access to the Internet was 'lossy' from 11 Dec 2001 1500hrs to 12 Dec 2001 1400hrs. ComCen was notified and the problem has since been rectified. Ping-loss indicator for the period is available here.

2001-10-07: SoC Network Service Disruption

Network access in SoC was disrupted on 7 Oct 2001 from 0815hrs to 0915hrs. This was due to failure in both the core switches which affected all routing functions in the core.

2001-09-20: Internet Service Disruption

Internet connection to certain overseas sites was disrupted from 20 Sep 2001, Tuesday, 10:00am - 02:45pm. This is due to problems with some overseas ISPs that are connected via Singnet. The prolem had been resolved since.

2001-09-03: SPNP Network Access Disrupted

Internet access was intermittently disrupted from about 1500hrs to 1630hrs. This was due to a problem on ComCen's SPNP DHCP server. Apparently the daemon program hanged and could not allocate IP addresses to requesting clients on the SPNP segment. They have restarted the DHCP server and internet access is now back to normal.

2001-08-20: Internet Access Disrupted

Internet access was intermittently disrupted from about 1100hrs to 1300hrs and again from 1730hrs to 2000hrs on 20 Aug 2001. This was due to a problem on ComCen's Internet firewall. Ping-loss indicator for the period is available here.

2001-08-19: Internet Access Disrupted

Internet access was intermittently disrupted from about 1430hrs till 2359hrs on 19 Aug 2001. This was due to a problem on ComCen's Internet firewall and affected all Internet access from NUS. Ping-loss indicator for the period is available here.

2001-08-06: Slow Internet Access

Congestion on Internet firewall from approximately 0900hrs to 1500hrs.

2001-08-02: Code Red Worm Impact on NUSNET

Network performance on NUS Computer Centre network was partially degraded from approximately 2000 hrs 1st August 2001 to 1100 hrs 2nd August 2001. This was due to the Code Red worm which flooded the Internet firewall with TCP connection traffic, resulting in degraded performance on the firewall.

SoC network was unaffected by the effect of the worm.

Ping-loss indicator to various destinations within NUS during the period is available here.