From: jonatale@xxxxxxxxxxxxx
Date: Thu Aug 16 2001 - 02:09:30 GMT-3
true, but, as ALWAYS, read carefully:
No, you're mixing apples and oranges:
2,000,000Mbits/secHTTP x 0.1secNonHTTP= 200,000bitsHTTPnonHTTP= .2bitsNoProto
Prashant Karunakaran wrote:
> Hi
> As per the formula Bc =Tc x CIR . wouldnt the answer be 2000000x0.1= 200000=
.2
> MBps?
> Prashant
> jonatale@earthlink.net wrote:
>
> > I'll assume link speed = 10Mbps and that by "MB" you mean Mbps. I'll also
> > ignore the effects of interpacket gap, exponential-backoff, tokens,
> > bit-stuffing, keep-alives, etc. Note: it helps me to use the units so that
I
> > can check the logic, for example Bc[bits] = CIR[bits/sec] * Tc[sec] => bits
=
> > (bits/sec) * sec.
> >
> > Custom Qing:
> >
> > 10Mbits/secTot * 100msecNonHTTP = 1,000mMbitsNonHTTP * (1/8)bytes/bit =
> > 125KbytesNonHTTP -- this is how many bytes to service in between servicing
the
> > HTTP.
> >
> > 125Kbytes/nonHTTP * 2MbpsHTTP/(10MbpsTot - 2MbpsHTTP)nonHTTP = 31.25Kbytes
-- > > this gives http 2Mbps of the traffic. > > > > So you can set your Q sizes to: > > HTTP: 31.25Kbytes = 31,250bytes > > default: 125Kbytes = 125,000bytes > > > > Bear in mind that this also assumes full link BW utilization. > > > > OT: > > There are allot of assumptions above...more exacting methods exist (for > > example: "Link-sharing and Resource Management Models for Packet Networks" > > -Sally Ford, ACM/IEEE"), but to my knowledge are not implemented by Cisco (in > > newer code?).Mike Schlenger wrote:
> Use the formula Tc = Bc/CIR (Tc= Interval Bc=Commited burst) along with > your access list to solve this problem. There is no need to "play" with > these values if you apply this formula correctly. > > Mike > CCIE #7079 > > -----Original Message----- > From: Jay Chandradas > To: Prashant Karunakaran > Cc: ccielab@groupstudy.com > Sent: 8/15/01 9:32 AM > Subject: Re: QOS question > > Hi prashant, > > There is a way to do it..that I know of... Basically you change the bits > > per interval, sustained to achieve the rate. Just play with the value > and > you will know the ratio. > > When you force the excess rate to 0 , you can see there is a definite > ratio between target rate and sustain rate. > > In your case, > > 2#sh traffic-shape > > Interface To2/0/0 > Access Target Byte Sustain Excess Interval Increment > Adapt > VC List Rate Limit bits/int bits/int (ms) (bytes) > Active > - 2000000 25000 200000 0 100 25000 - > r2# > > Hope this helps > > Jay. > > At 11:19 PM 8/14/2001 -0700, Prashant Karunakaran wrote: > >Hi > >I came accross this problem wherein on a router interface i need to > >provide 2 MB of the bandwidth on the interface to HTTP traffic every > >100ms. I thought of using the rate-limit command on the interface with > >an access-list permiting www traffic, but i couldn't find any option to > >set the interval of 100ms. > >Is there any other command to get this done? > >Thx > >Prashant > >**Please read:http://www.groupstudy.com/list/posting.html > **Please read:http://www.groupstudy.com/list/posting.html > **Please read:http://www.groupstudy.com/list/posting.html **Please read:http://www.groupstudy.com/list/posting.html
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