From: Mark Lasarko (mlasarko@co.ba.md.us)
Date: Sun Jan 15 2006 - 12:10:12 GMT-3
Here's my best explanation...
1000000 bytes equals:
8000000 bits
or
1000000 bytes
or
976.562 kilobytes (KB)
or
.9537 megabytes (MB)
whereas 1 megabyte equals:
8388608 bits
or
1048576 bytes
or
1024 kilobytes (KB)
or
1 megabytes (MB)
Confused yet?
Don't worry a lot of people, many with their #'s, still are :)
I have seen this often misinterpreted and/or otherwise misunderstood.
See, data file size is measured in binary.
This uses the binary number system,
which is counted by factors of two...
(1, 2, 4, 8, 16, 32, 64, etc)
And the nearest binary number to 1,000 is 2^10 or 1,024;
Therefore 1,024 bytes was named a Kilobyte.
At the end of the day, though a metric "kilo" equals 1,000
(1 kilogram = 1,000 grams);
A binary "Kilo" is actually 1,024 bytes.
(1000 does compute using "2^X")
Meanwhile, in regards to the T1 bandwidth...
(1) T1 = 1536 kbps = 24 timeslots with 64k each
The additional 8kbps is for overhead.
As for verification on the IOS CLI:
"GS_Router# show service-module serial 0
Module type is T1/fractional
Hardware revision is B, Software revision is 1.1 ,
Image checksum is 0x2160B7C, Protocol revision is 1.1
Receiver has AIS alarm,
Unit is currently in test mode:
line loopback is in progress
Framing is ESF, Line Code is B8ZS, Current clock source is line,
Fraction has 24 timeslots (64 Kbits/sec each), Net bandwidth is 1536 Kbits/sec"
This particular example is quite clear.
Wish I could say the same for more of this stuff :)
When it really matters ask the procotor or post to the board of the vendors' practice lab.
HTH,
~M
>>> Peter McCreesh <petermccreesh@gmail.com> 01/15/06 7:21 AM >>>
Can't answer that one.
Maybe someone else out there has an answer.
On 1/15/06, InderpalS@mindscapeit.com <InderpalS@mindscapeit.com> wrote:
>
> Ahhh.....another doubt now....T1 = 1536 or 1544??
>
> similarly 1mb = 1024k or 1000k??
>
> I have seen 1000k and 1536k used in many examples...
>
> ------------------------------
> *From:* Peter McCreesh [mailto:petermccreesh@gmail.com]
> *Sent:* Sunday, January 15, 2006 3:41 PM
> *To:* InderpalS@mindscapeit.com
> *Cc:* ccielab@groupstudy.com
> *Subject:* Re: Bandwidth on interface
>
> I see what you mean.
>
> It'll probably work as the default should be 1544K as you have said but
> might be one of those for the proctor to clarify I guess.
>
>
> On 1/15/06, InderpalS@mindscapeit.com <InderpalS@mindscapeit.com > wrote:
> >
> > Well said Pete but now the point is what is the best practice in terms
> > of ccie lab? If asked to guarantee 256k bandwidth for a class and
physical
> > interface speed is T1, will it make any difference if bandwidth is not
set
> > on interface?
> >
> > ------------------------------
> > *From:* Peter McCreesh [mailto:petermccreesh@gmail.com]
> > *Sent:* Sunday, January 15, 2006 3:19 PM
> > *To:* InderpalS@mindscapeit.com
> > *Cc:* ccielab@groupstudy.com
> > *Subject:* Re: Bandwidth on interface
> >
> > I think it determines what is available from the BW command on the
> > interface and if this is, say, 64K and you set a policy to apply 128K to
a
> > class, it won't let you as it will give the following error message (if
the
> > class-default is assigned 128k and applied to int s0/1):
> >
> > I/f Serial0/1 class class-default requested bandwidth 128 (kbps),
> > available only 48 (kbps)
> >
> > So the BW needs to be correctly set (or at least set above what you
> > need) as far as I can see but i am open to correction on this.
> >
> > Regards,
> >
> > Pete
> >
> >
> > On 1/15/06, InderpalS@mindscapeit.com < InderpalS@mindscapeit.com >
> > wrote:
> > >
> > > I know that default is 75% minus (bandwidth for priority
> > > queues) but if bandwidth value is given in kbps under policy map how
does it
> > > help router to set bandwidth value under interface?
> > >
> > > ------------------------------
> > > *From:* Peter McCreesh [mailto:petermccreesh@gmail.com]
> > > *Sent: *Sunday, January 15, 2006 2:58 PM
> > > *To:* InderpalS@mindscapeit.com
> > > *Cc:* ccielab@groupstudy.com
> > > *Subject:* Re: Bandwidth on interface
> > >
> > > Hi Inder,
> > >
> > > The fact that by default CBWFQ only uses 75% of available BW, this may
> > > affect the amount you can assign to each class.
> > >
> > > Other than that, i'm not sure.
> > >
> > > Regards,
> > >
> > > Pete
> > >
> > >
> > > On 1/15/06, InderpalS@mindscapeit.com < InderpalS@mindscapeit.com >
> > > wrote:
> > > >
> > > > Hi Group,
> > > >
> > > >
> > > >
> > > > When using CBWFQ, it is necessary to set interface bandwidth?
> > > >
> > > >
> > > >
> > > > Scenario 1---------> I guarantee bandwidth for a class using
> > > > Bandwidth (
> > > > )kbps command in policy map
> > > >
> > > >
> > > >
> > > > Policy-map policy1
> > > >
> > > > Class class1
> > > >
> > > > Bandwidth 256
> > > >
> > > >
> > > >
> > > > If we still need to set bandwidth on interface then why since we are
> > > > giving
> > > > guaranteed bandwidth value in policy map.
> > > >
> > > >
> > > >
> > > > Scenario 2---------> I reserve bandwidth for a class using bandwidth
> > > > percent
> > > > command in policy map
> > > >
> > > >
> > > >
> > > > Policy-map policy1
> > > >
> > > > Class class1
> > > >
> > > > Bandwidth percent 25
> > > >
> > > >
> > > >
> > > > I understand in this scenario, interface bandwidth needs to be set
> > > > so that
> > > > router can calculate available bandwidth and assign to class.
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > Any inputs are appreciated!
> > > >
> > > >
> > > >
> > > > Regards,
> > > >
> > > > Inder
> > > >
> > > > 1/15/2006 10:55:46 AM
> > > >
> > > > Disclaimer
> > > >
> > > >
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