nexSIP

I have installed these things before... but im wondering how to you determine when its time to upgrade to center stage?

I would assume you would have to monitor the traffic on the PPN.. but how and what is the threshold?

thanks!

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ahays

Center stage switching is required when it become time for more than 3 port networks. Up to three port networks can be diect connected (just like an si) but when it comes time for the forth (or more) then connectivity can be established only via a center stage switch.

regs,

.al.

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nexSIP

So what you are saying is i can add shelves until I have maxed out the 3 port networks? I though you had to do an analysis or something as to the call volume your port network is doing...

I have a potential customer who had 3 port networks but 1 of the port networks only has 1 shelf. Its heavly trunked. Would be nice for them to just add another shelf to the port network.

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ahays

That is correct. The sole purpose of the center stage switch is to expand connectivity beyond three port networks.


Well, traffic analysis is necessary for ANY addition ... even in an si. Adding another carrier (whether it be G3r, G3si, S8xx0, whatever) will only complicate the problem if it increases traffic in the port network beyond time slot capacity. Therefore, if the addition of another carrier would push his traffic beyond capacity limits, then the additional carrier would best be installed into a new port network ... and if that takes you to 4 port networks then a center stage switch will also be necessary.

If they're expanding for stations and not trunks, then odds are the'd be OK to add an additional carrier in the 3rd port network ... BUT ... if they wish to expand trunking then they would likely need to add an additional port network or add an additional carrier to the 3rd port network and then move station ports to the new carrier and balance the trunking load to the other port networks in the locations from whence the station circuit packs came.

regs,

.al.

__________________
Al Hays, ACE, MCSE, CCNA
Homepage: http://www.jeral.com/
Training: http://www.jeral.com/avaya-learning.html

nexSIP

so is there a report to show time slot activity?

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ahays

No. Traffic engineering is a bit more complex than a single report can produce. So, I had to pull out and dust off an old textbook from BSG210H2 ... Definity ECS Basic Design and Configuration (yes, it's true ... I took some DS courses at one time).

The TDM bus consists of two eight-bit busses with 256 timeslots per bus. That's 512 timeslots per port network. 28 timeslots are dedicated to control and tones leaving 484. That means a single port network can ideally support 242 simultaneous conversations. However, conversations between port networks require 4 timeslots (2 in each). Above and beyond all that are the actual traffic volume considerations ... call center, queueing, announcements, the list of erlang considerations goes on and on.

Here's a basic rule of thumb: If you engineer for 80% capacity with trunking then you're generally going to be covered for intercom traffic and additional overhead. SInce 242 simultaneous conversations would require 10 T1's then 80% would be a maximum of 8 T1's in a given port network. The station side of this equasion is already considered since it would be one side of the conversation coming from the trunk. It's the rule that I have always employed when attempting to balance a multi-port network system and it's always served me well.

regs,

.al.

__________________
Al Hays, ACE, MCSE, CCNA
Homepage: http://www.jeral.com/
Training: http://www.jeral.com/avaya-learning.html

PBXtech.info

 

nexSIP

that is exactly what i was looking for. thanks a ton!

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