Fiber Optic Essentials

146 Fiber Optic Essentials

in managing the product. Also, router protocols such as Open Shortest

Path First (OSPF) and Border Gateway Protocol (BGP) are desirable

because they are more flexible than “static” routers; OSPF can be used

to dynamically route information to multiple destinations. Many types

of network management software are available, in datacom applications,

these are often based on standard SNMP protocols supported by many

applications such as HP Openview, CA Unicenter, and Tivoli Netview.

IP network management can be somewhat complex, involving consider-

ations such as the number of IP addresses, number of gateway elements,

resolving address conflicts in an IP network, and other considerations.

Telecom environments will often use the TL-1 standard command codes,

either menu-driven or from a command line interface, and may require

other management features to support a legacy network environment; this

may include CLEI codes compatible with the TERKS system used by

the telecommunications industry and administered by Telcordia Corp.,

formerly Bell Labs [11]. User-friendly network management is important

for large DWDM networks, and facilitates network troubleshooting and

installation; many systems require one or more personal computers to run

network management applications; network management software may

be provided with the DWDM, or may be required from another source.

It is desirable to have the PC software pre-loaded to reduce time to

installation (TTI), pre-commissioned and pre-provisioned with the users

configuration data, and tested prior to shipment to insure it will arrive

in working order. Finally, note that some protocol-specific WDM imple-

mentations also collect network traffic statistics, such as reporting the

number of frames, SCSI read/write operations, MB payload per frame,

loss of sync conditions, and code violations (data errors). Optical manage-

ment of WDM may also include various forms of monitoring the physical

layer, including average optical power per channel and power spectral

density, in order to proactively detect near end-of-life components or

optimize performance in amplified WDM networks.

References

[1] DeCusatis, C. (ed.) (2001) Handbook of Fiber Optic Data Communication, 2nd

edition, Academic Press: New York.

[2] “Optical interface for multichannel systems with optical amplifiers”, draft standard

G.MCS, annex A4 of standard COM15-R-67-E, available from the International

Telecommunication Union (1999).