I think the best IOS version to use for VoIP came up in an earlier thread,
so you might want to search the archives or perhaps people can remind us.
Cisco made quite a few updates and bug fixes in the QoS for voice about a
year ago, but I can't recall the IOS version number. Help anyone?
Priscilla
At 09:12 AM 1/10/01, Ishtiaque Mahbub wrote:
>All,
>
>Thank you so much for contributing. (Oh my God, Priscilla has given an
>answer to my question!! this must be my big lucky day!! have taken a print
>out of the reply and kept it in my personal file, i will show it to my
>grand child someday!!)
>
>One last question though, and that is, if IOS 12.x is good enough to
>implement VoIP, or do I need to ask for additional features? Pardon for
>not adding the question in the first place (I am bit sluggish, as you may
>have noticed, in my thinking process!)
>
>
>Regards
>
>Ishtiaque
>
>>From: Priscilla Oppenheimer <[EMAIL PROTECTED]>
>>To: "Ishtiaque Mahbub" <[EMAIL PROTECTED]>,[EMAIL PROTECTED]
>>Subject: Re: Bandwidth constraints for VoIP
>>Date: Tue, 09 Jan 2001 15:45:59 -0800
>>
>>Each CODEC has different capabilities for compressing voice, so you'll have
>>to know which CODEC you want to use first.
>>
>>The compressed voice is then put into an IP frame, so you will need to take
>>into account the bandwidth used by headers of the following sizes:
>>
>>20-byte IP header
>>8-byte UDP header
>>12-byte Real-Time Protocol (RTP) header
>>
>>On point-to-point links those headers can be compressed down to just a few
>>bytes. Even the IP header can be compressed if it's a point to point link
>>and IP addressing isn't needed for forwarding to the next hop.
>>
>>If you use Voice-Activity Detection (which uses no bandwidth during
>>silence) you can further reduce bandwidth requirements.
>>
>>Finally, you need to take into account the data-link header, PPP, Frame
>>Relay, whatever.
>>
>>According to a chart that I picked up at Networkers a couple years ago,
>>here are a few examples:
>>
>>G.729 CODEC on PPP without compressed IP/UDP/RTP and without VAD uses
>>26.4Kbps.
>>
>>G.729 CODEC on PPP with compressed IP/UDP/RTP and without VAD uses 11.2 Kbps.
>>
>>G.729 CODEC on PPP with compressed IP/UDP/RTP and with VAD uses 5.6 Kbps.
>>
>>G.729 CODEC on Frame Relay without compressed IP/UDP/RTP and without VAD
>>uses 25.6Kbps.
>>
>>G.729 CODEC on Frame Relay with compressed IP/UDP/RTP and without VAD uses
>>10.4Kbps.
>>
>>G.729 CODEC on Frame Relay with compressed IP/UDP/RTP and with VAD uses
>>5.2Kbps.
>>
>>I would copy and paste the whole chart but I only have hard copy. You
>>should be able to find such a chart somewhere though.....
>>
>>Priscilla
>>
>>
>>At 11:47 AM 1/9/01, Ishtiaque Mahbub wrote:
>>>Hello Group!
>>>
>>>A very happy new year to you all!
>>>
>>>I was wondering if any one could advise what is the minimum Bandwidth
>>>required for Voice Over IP installation on Cisco Routers (Router Series will
>>>be 2600).
>>>
>>>Is 64kbps is too steep for 4 simultaneous voice operations?
>>>
>>>Suggestion, advices welcome.
>>>
>>>Regards
>>>
>>>Ishtiaque
>>>
>>>_________________________________________________________________________
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>>>
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>>
>>
>>________________________
>>
>>Priscilla Oppenheimer
>>http://www.priscilla.com
>
>_________________________________________________________________________
>Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com.
________________________
Priscilla Oppenheimer
http://www.priscilla.com
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