Computer News No. 122  July-Aug. 2006

HARNET Goes Optical

    1. Background
    2. Advantages of optical network
    3. Network configuration and implementation schedule
    4. HARNET-Internet link upgrade

1. Background

To cope with increasing demands for Internet bandwidth to facilitate the University's research and academic activities, the Computer Centre has been working with the JUCC (Joint Universities Computer Centre) on the upgrade of the HARNET-Internet connection which links the eight tertiary institutions in Hong Kong to the Internet.

Currently, the HARNET is made up of a local wide-area-network that connects the eight tertiary institutions, and is connected to overseas networks through international links.  The local network is based on metro Ethernet technology provided by a local service provider.  This networking model has been in use for some years.

Optical networking technologies have been widely implemented in the world of international research and education (R&E) networks in recent years.  Next generation networking projects, such as the US National Lambda Rail (NLR) with optical network being run on dark optical fibers, allow researchers to have on-demand dedicated bandwidth to run high bandwidth research applications.  The JUCC intends to upgrade to the Next Generation Internet technologies, and therefore has planned to convert the HARNET backbone  to an optical-network based on Dense Wavelength Division Multiplexing (DWDM) optical technology this year.

2. Advantages of optical network

The DWDM is a technology to optimize the data carrying capacity of a single optical fiber, given that the availability of optical fiber is of high cost.  Thus different network services (e.g. data traffic, high-definition video stream, SAN storage connection, etc) can be carried on different wavelengths (lambda) over a single fiber connection.  These capabilities of optical networking can facilitate different academic research activities.

3. Network configuration and implementation schedule

As a starting technology for the new HARNET optical backbone, there will be two 10Gbps rings covering all 8 HARNET institutions.  Each 10Gbps ring will have fail-over protection, resulting in 5Gbps usable bandwidth per ring.  Besides, a new set of optical switching equipment will be installed at each HARNET institution.  In the initial set-up, the new optical HARNET backbone will provide Gigabit Ethernet (GE) connections and Fiber Channel (FC) connections.  The FC connections enable collaboration between HARNET institutions for remote backup based on SAN connections.

Two central exchange points will be established at HKU and CUHK and the GE wide area network connections from the other HARNET institutions will be connected to them.  The central exchange points in turn connect to the network of the Internet service provider PCCW, which was selected after a tendering process.

The whole HARNET upgrade process will be more complicated than those in previous years as extensive network backbone reconfiguration works are required.  The Computer Centre has been working closely with the JUCC on the upgrade since July 2006.  We will report on further progress on the new optical HARNET in the coming issue of the Computer News.

4. HARNET-Internet link upgrade

In addition to the optical HARNET upgrade, the HARNET-Internet link will be upgraded from 380Mbps to 440Mbps in early September 2006 while the HARNET-HKIX link is maintained at 500Mbps and the HKU-HARNET link is maintained at 300Mbps.  Connections to Internet2 (45Mbps), Mainland China's CERNET (China Education and Research Network) (155Mbps) and Taiwan's TANET (Taiwan Academic Network) (100Mbps) remain unchanged.