Availability & Quality

[kikikiki]

While link engineering we speak of the Availability as 99.999% etc. but we fail to see whether the Quality of the link is maintained during the available time. i.e. the allotted time for ES, SES, UAT must not be exceeded. This is precisely defined by the G 826 parameters. My Query is : My typical SDH hop length is 4Km in 18 GHz. How do I feed in values so that the Quality of my link during the Available time is ensured? If I design my Network with 99.995% availablity in a Ring will the G 826 parameters be met?
Thanks
kikikiki

[Anuj]

Hi
If you look at ITU-R you can find out the values of ES,SES,UAE and DM as applicable for your link.

Regs

[kikikiki]

that's what i am asking for. Please give me the values for ES, SES etc

[ABDUL DURRANI]

If I understand your question correctly what you are asking is: How do we know that during available time the link is also meeting its quality or performance objectives.

You can calculate the SES for your link if you check the ITU Rec G 826 or see a good paper by Treve Maning on the web.


Lucky for us in North America, the quality and performance objectives are the same and this simplifies things for us.

Path calculations predict the time below zero or below the point where the radio threshold will start giving BER > 10 -3. If you have done a proper design and your outage time is 30 seconds in the worst month or 99.999 % availability, your should not worrey about the link performance. Now going back to your question about the assurance of the link qulaity or the SES, clearly if your designed fade margin only crosses the radio threshold level for 30 seconds in the worst months, we can say that only during these 30 seconds the BER will exceeded 10-3 or the accumulation of SES ( a second in which BER > 10-3). Therefore if you have designed your link for 99.999 % availabilty your performance is also 99.999%. This you will only know during field measurments and during the wordt fading periods.

Hope this answers your questions. With ring you should be OK. Good luck