Hi Priscilla
I found the solution.
Here it is:
1.544Mbps = 192KB/sec
Router begins to forward at the rate of 64KB/sec
means it is tranfering at the rate of 3 packets/sec
i.e it will take 1/3 sec. or 333 ms to transfer one
packet.
Now it's getting packets at the rate of 5000
packets/sec i.e one packet in every 1/5000 sec. or
1000/5000 = .2 ms
so it will get 500 packets in 500x.2=100 ms
So by the time router will forward first packet in
333ms, it's buffer will be full.
Thanks for your help.
--- Priscilla Oppenheimer <[EMAIL PROTECTED]> wrote:
> Oops. I was multiplying 512 bits times 5000 bits per
> second. I guess I lost
> a digit. Sorry.
>
> Now it's a much more interesting problem!
>
> Priscilla
>
> At 06:22 PM 10/10/00, Brian wrote:
> >On Tue, 10 Oct 2000, Priscilla Oppenheimer wrote:
> >
> > > At 12:01 PM 10/10/00, Arun Upadhyay wrote:
> > > >Can anybody please help in solving this
> problem?
> > > >
> > > >A router is connected to a T1 line which has
> the
> > > >maximum speed of 1.544mbps. The router begins
> to
> > > >forward 64bkps packet at 5000 packets per
> second,
> > >
> > > Do you mean 64-byte packets? If you convert that
> to bits it's 512 bits.
> > > 5000 packets of that size per second is 560,000
> bits per second, which
> > is a
> > > lot less than 1.544 Mbps so not much buffereing
> will be needed at all. You
> > > could have just one buffer and no packets should
> ever get dropped.
> >
> >Priscilla,
> >
> >How did you come up with 560,000 bits per second?
> Can you break that down
> >for me, I know I must be doing something wrong:
> >
> >64bytes * 8 = 512 bits
> >512 bits * 5000 packets = 2560000 bits
> >
> >brian
> >
> >
> >
> >
> > >
> > > >there are 500 buffers available.
> > >
> > > How big are the buffers? Can we assume they are
> 64 bytes also?
> > >
> > >
> > > >Approximately how
> > > >long before the link is complelety saturated,
> the
> > > >buffers are full and the router begins to
> discard.
> > >
> > > If you are trying to get help with questions
> like this that appear on the
> > > CCIE written test and practice exams, you will
> want to give us an example
> > > of where the WAN link is oversubscribed. For
> example, if the offered load
> > > to the WAN link is 110% more than the WAN link
> could handle, 500 buffers
> > > would get used up in about 5000 packet times. (I
> think? Comments anyone?)
> > >
> > > In reality, packets don't arrive at a constant
> rate, so much more
> > difficult
> > > math and queuing theory is required, and that
> goes beyond the research and
> > > thinking I'm willing to do right now. &;-)
> > >
> > > Priscilla
> > >
> > >
> > >
> > > > Thanks.
> > > >
> > > > Arun
> > > >
> > > >=====
> > > >Arun Upadhyay
> > > >SE Engineering
> > > >MCSE CCNA CNA
> > > >
> > >
> >__________________________________________________
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> > > ________________________
> > >
> > > Priscilla Oppenheimer
> > > http://www.priscilla.com
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> >-----------------------------------------------
> >Brian Feeny, CCNP, CCDP [EMAIL PROTECTED]
> >Network Administrator
> >ShreveNet Inc. (ASN 11881)
>
>
> ________________________
>
> Priscilla Oppenheimer
> http://www.priscilla.com
>
> **NOTE: New CCNA/CCDA List has been formed. For more
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=====
Arun Upadhyay
SE Engineering
MCSE CCNA CNA
__________________________________________________
Do You Yahoo!?
Get Yahoo! Mail - Free email you can access from anywhere!
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