bandwidth over SCN 2

[AlfredRock]

Hi Guys,

We setup a SCN with 3 IPO and it´s working OK, but we have an issue with the Bandwidth.

We select the codec G729 as preferred over the SCN and when we make a call it uses 25kpbs to establish the call, then drop to 6-8 kbps and that's great but when we put the call on hold it ups again to 25kbps.

Do you have any idea how to lower the bandwidth of the call when on hold?

as we have limited bandwidth, 6-8 kbps are great per call but no 25 per call.


IPO 1 - central
IPO 2 - shops
IPO 3 - branch office

We have over 250 different littles shops and we have to have a 1603 phone in each.
We have an IPO in central offices to connect the 1603.
We have satelite network with limited bandwidth to interconnect the shops with the central

 

[amriddle01]

This is normal, it's due to call control/progress messages and also just normal network overheads, you need to make your network fit what you want run over it...not the other way around, if that isn't possible you need to reconsider the capabilities of the network

 

[smokinjoe2938]

do not believe you can lower bandwidth just because you are on hold, the reason the bandwidth drops off most likely is because of more traffic going across the scn pipe, also what is the size of the circuit between the sites? also to consider what are the service level of agreement with the circuit provider? lots to consider with the wondeful world of voip

acss sme acis sme acss cm 5.2.1 acss cm and cmm acss aura messaging.

 

[AlfredRock]

ok, guys

The only thing is:

Whenenver I make the call if the IPO1 (with external digital lines, over 300 IP and Digital extensions) place the call on hold the bandwidth ups to 25k
when the IPO2 (with only IP extensions and the SCN) place the call on hold, the bandwidth stays at 8k

it can be because of the digital and analog lines it uses the extra bandwidth to call control, even if it doesn't use it in the call?


regards!!!!

 

[amriddle01]

Even if you find the answer ....it's beyond your control, so your chasing your tail really

 

[intrigrant]

I really dislike it but enabling silence suppression might do the trick.

If setup SCN properly a call on hold will be placed on hold in the system were the call arrived initially.

With a properly setup SCN I mean that each IP line has uniqe incoming and ourgoing line IDs.

Example four sites with mesh trunking, name site A node 1, Site B node 2, Site C node 3 and site D node 4.
A line going from A to B would have on site A a incoming and outgoing number 12 ( from 1 to 2 ) and on Site B the number 21 ( from 2 to 1 )
A line going from A to C would have on site A a incoming and outgoing number 13 ( from 1 to 3 ) and on Site C the number 31 ( from 3 to 1 )
etcetera, then each trunk has uniqe ID's and anti-tromboning ( aka route optimalisation ) will work fine and a call coming from A but answered in B and put on hold should be held on Site A and get MOH from Site A.
One way to test this is to give each site its own MOH music and try it.
With anti tromboning you reduce the number of call paths to a minimum and so use as less bandwith as possible.

Planning a SCN is mandatory, never set it up on the go.

 

[TexasBear]

Is MOH being provided at the source or at the remote site? Is QoS and traffic management set for the ports being used across the VPN (this makes a big difference)?

 

[tlpeter]

25k being a problem is really ridiculous!!!
Get a proper link and invest in it or loose customers because of not doing it.


BAZINGA!

I'm not insane, my mother had me tested!

 

[AlfredRock]

thanks guys!!!

amriddle - thanks,the call control tip was great!

intrigant - thanks for your response I´ll try your setup, because the lines number are the same today, each site has its own MOH

texasbear - thanks for your response, each site provide its own MOH, QoS and traffic over the satelite link are OK, and in the local network switches and routers everything is OK.

tlpeter - I know!!! the customer wants to optimize the bandwidth and I understand they´re pushing but this is Mexico and the ISP here are veeeery expensive and not so good, thanks!!


thank you all!!!

regards!!!

 

[intrigrant]

@tlpeter, not every region in the world is as lucky as were we live. We can have a 500Mb glassfiber connection almost anywere in the Netherlands.
In Belgium there are a lot of regions were a 2Mb DSL connection is the maximum available at a very high price ( €450,00 / $620 ) a month, so I can understand the need of consuming the minimum possible bandwith.
Anti-tromboning, Silence suppression and as a last resort the G.723 codec, all can help reducing bandwith consumption.

 

[intrigrant]

ADDENDUM : If a DSL connection is not enough and you have ISDN lines then you can create dial-up IP connections in the IP Office were you can have 2,5 calls per 64K ISDN trunk. Depending on the calling tariffs and the number of calls between sites it can be cheaper as a DSL connection.

 

[AlfredRock]

indeed here in Mexico the bandwidth is still an issue, even the ISDN lines are an issue because we use R2 MFC

the satellite network our customer have is limited in bandwidth so they need to optimize it, but I already talk to them and it's clear 25k is the best they'll get.

still.... thanks to everyone!!!