Thanks mate. 

 

From: Anthony Holloway [mailto:[email protected]] 
Sent: 15 April 2015 21:46
To: abbas Wali
Cc: [email protected]
Subject: Re: [cisco-voip] PER CALL BANDWIDTH CONSUMPTION OVER ETHERNET+802.1Q

 

I read somewhere that a phone could generate up to 2.5x call traffic with its 
BIB.  Multiplying by 3x would still be acceptable, I would think.

 

The 8000 is a burst threshold over the policed rate.  It's always been 8000 in 
my experience, but probably only because no one knows enough to adjust it  You 
cannot have an average and a max rate with voice.  It's constant (excluding 
VAD).  Video on the other hand is variable.

 

If you are studying for your CCIE, I can share with you that Cisco has publicly 
stated they have some percentage of forgiveness.  I.e., If they say 3 g711ulaw 
calls worth of bandwidth, and I enter 90*3=270, but you enter 93*3=279 (or even 
round up to 280), we would both get the points.  What the percentage is, I 
don't recall.  I want to say it was like 10%.  So for every 100kbps, you can be 
plus or minus 10kbps.

 

On Wed, Apr 15, 2015 at 1:00 PM abbas Wali <[email protected] 
<mailto:[email protected]> > wrote:

Anthony, 

 

yes makes sense. but for the sake of argu. a single phone with even with BIB 
how many max g711 streams it can get to. 3? if so, for a safe figure can 
multiply by 3. 

moreover, I dont really understand this statement ​police 90500 8000 exc drop - 
as per docs, the actual transmission is 8k but on the avg. the max is 90k ( plz 
correct if wrong)

 

On 15 April 2015 at 18:10, Anthony Holloway <[email protected] 
<mailto:[email protected]> > wrote:

After reading the Medianet document, I'm certain they are just giving you an 
example, not a definitive answer nor the best practice.  While 128kbps does 
police the port to a single g711ulaw call, it also allows for a little wiggle 
room, which I like.  If you are looking for the absolute minimum bandwidth 
needed for a g711ulaw call, you could go lower than 128kbps, but you wouldn't 
gain anything.  Don't forget that the BIB of the phone could cause more than a 
single call's worth of RTP to ingress the switch port, in which case your 
128kbps would not be enough and you would have issues with things such as 
network recording or silent monitoring.

 

On Wed, Apr 15, 2015 at 9:19 AM abbas Wali <[email protected] 
<mailto:[email protected]> > wrote:

medianet is 

http://www.cisco.com/c/en/us/td/docs/solutions/Enterprise/WAN_and_MAN/QoS_SRND_40/QoSCampus_40.html

 

Vik's post 

http://www.collabcert.com/blog/qos/how-much-bandwidth-does-1-call-consume/

 

 

On 15 April 2015 at 13:44, Anthony Holloway <[email protected] 
<mailto:[email protected]> > wrote:

Can you link us to the sources in question? I personally need a little more 
context to go with your question. 

In general, policing a single g711ulaw call is around 93kbps, and rounding it 
to 100kbps still achieves the goal of policing a single call. And yes, a class 
based policer would police media and signaling separately. 

Also, I saw something on medianet at last year Cisco Live, but other than that, 
I'm clueless about medianet. I can't say if and how things changed once 
medianet came in to the picture. I'm sure Vik wasn't considering that either, 
based on the fact that he teaches CCIE Collab boot camps, and medianet is not a 
part of the blueprint. 

On Wed, Apr 15, 2015 at 4:22 AM abbas Wali <[email protected] 
<mailto:[email protected]> > wrote:

hi all,

 

Vik Malhi posted that for a successful g711 call 

HQSW(config-pmap-c)#police 90500 8000 exc drop ! 0 packet loss
now, as per Ciso medianet 4
The VoIP and signaling traffic from the VVLAN can be policed to drop at 128 
kbps and 32 kbps, respectively (as any excessive traffic matching this criteria 
would be indicative of network abuse)
Question is 128 kbps supports 1 single voice stream of g711 OR if you go with 
Vik, you need to multiply 90500 with the number of calls you need on that port. 
I will assume that the sig is classified differently and handled by diff 
policer on that port.
 
many thanks

 

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Abbas Wali

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