Optical Monitoring

JANET(UK) has two projects in this area. They are currently on-hold while the new Netsight system is completed:

• Optical Splitters
  Data concerning the traffic being passed on a network link is available from many sources. Most monitoring methods however, cause some performance impact on the network or equipment being monitored. Network flow monitoring for example can record the basic attributes of IP flows passing through a router, yet it places a load on the router and at high link speeds it is impossible to record all flows.
  
  The only way to observe all traffic passed on an optical link without impacting the link is to use an optical splitter, which "steals" some of the optical signal whilst imposing negligable load on the link.
  
  In 2007 JANET(UK) deployed optical splitters at two JANET core routers. The splitters sit in-line across several links, with the split signals fed into a Glimmerglass optical switch. The Glimmerglass switches can be remotely controlled to direct a particular input signal to the output port, allowing the operator to remotely select which link they wish to monitor. This provides an alternative perspective on traffic monitoring to technologies such as network flow monitoring. While a router may be able to provide network flow data for all of its links, at high speeds the data represents only a sample of the total traffic passed. In comparison, use of an optical splitter and switch provides all of the data on a link, albeit for a single link.
  
  The MASTS project will be the first user of this capability. Note that strict limitations satisfying the RIP and Data Protection Acts are in place for the use of this data. JANET(UK) also have a policy and legal framework controlling the JANET community's access to such data.

• Optical Layer Network Monitoring
  This work concerns monitoring the optical components in a network and reporting on their status. Note that the focus is on monitoring purely optical equipment rather than the optical interfaces of routers and other devices which can already be monitored via traditional SNMP polling. The measurement interfaces of optical equipment may be required to use TL1 (the Transaction Language 1 management protocol) or exchange data with optical Network Management Systems. Equipment is also now appearing which provides an SNMP capability.
  
  JANET(UK) are investigating the feasibility of gathering optical layer data from Ciena and Nortel equipment within the JANET and TVN (Thames Valley Network) networks.
  

For further information please contact Jeremy Sharp.