Quote:>Hi,
>I am implementing network and want to use ATA 186 Phones & Cisco
>Callmanager for voice .
>I would like to have some information on the following questions:
>1.How is the broadcast in the network ?( Do they have a continuous
>connection or keepalive mechanism )
If the ATA is using the mgcp/sccp firmware then there are minimal
keepalive packets sent to the CallManager. Same as a 7960 phone,
every minute I think. If you're using H323 firmware, there are no
keepalives from the ATA.
Quote:>2.How much bandwidth does one point to point call require ?
Depends on the codec you use. G711 is virtually no compression and
best quality and uses 80k in each direction.
Quote:>3.Once the call is setup between 2 phones do all the voice packets get
>routed thru the call manager or the 2 phones can communicate
>independently and only signalling remains with the call manager ?
Yes. CM only handles call setup and teardown, not the actual voice
RTP packets. This applies to both firmwares. The exception is for
conference calls where all phones talk directly to the CM.
Quote:>We have a serious bandwidth crunch as most of it is used by some other
>critical application which gets affected (i.e. IP packets get lost
>)when we connect the IP phones to the network and try recognising them
>via Call Manager.
You will need to address the QOS issues. What switches are you using?
They need to prioritize based on COS or TOS so that big file transfers
don't squash voice traffic. If you can't guarantee that the phones
will have bandwidth, you will be very disappointed with voice-over-ip.
-Chris
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