Re: QoS

I was not quite right. I have readed the RFC and now I understand it.
bit 0-1-2 are precedence bit 3-4-5-6 are TOS bits. bit 7 (must be zero)
So with the route map you will set bit 3-4-5-6 which will be 1100. So the
you actualy get 11000 with the 7th (must be zero bit) this makes it 10111000

Kind regards,

Maarten Vervoorn

2010/5/12 Maarten Vervoorn <mr.vervoorn_at_gmail.com>

>
>
> ---------- Forwarded message ----------
> From: Maarten Vervoorn <mr.vervoorn_at_gmail.com>
> Date: 2010/5/12
> Subject: Re: QoS
> To: Kambiz Agahian <kagahian_at_ccbootcamp.com>
>
>
> Hi Kambiz,
>
> So the reason why is because it is devided in two hex bit. Because normaly
> 101 would be 1010 0000 (160) if you converd it into TOS bits. The last hex
> bit is the tos bits you can configure in you r route-map. and the first
> represents the precedence.
>
> I see how this is done. I only find this confusing
>
> Thanks for you response.
>
> Maarten Vervoorn
>
> 2010/5/12 Kambiz Agahian <kagahian_at_ccbootcamp.com>
>
> Maarten,
>>
>> This is one of the grandfather questions; I guess the last time it was
>> seen on the GS was back in 7-8 year ago :)
>>
>> You're after EF so you'll come up with 101110
>>
>> Padding with Zero's: 0101 1100
>>
>> 0101 ->HEX 5 -> IPP (Prec)
>> 1100 ->HEX 12 -> TOS
>>
>> That's why you see:
>> set ip precedence 5
>> set ip tos 12
>>
>>
>> Please see RFC-1349 for more details.
>>
>> HTH
>>
>> --------------------------
>> Kambiz Agahian
>> CCIE (R&S), CCSI, WAASSE, RSSSE
>> Technical Instructor
>> CCBOOTCAMP - Cisco Learning Solutions Partner (CLSP)
>> Email: kagahian_at_ccbootcamp.com
>> Toll Free: 877-654-2243
>> International: +1-702-968-5100
>> Skype: skype:ccbootcamp?call
>> FAX: +1-702-446-8012
>> YES! We take Cisco Learning Credits!
>> Training And Remote Racks: http://www.ccbootcamp.com
>>
>>
>>
>>
>>
>> -----Original Message-----
>> From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of
>> Maarten Vervoorn
>> Sent: Wednesday, May 12, 2010 12:25 PM
>> To: Cisco certification
>> Subject: Re: QoS
>>
>> Thanks for you response
>>
>> The binary value of 12 is 1100. if you have 8 bits this and the left six
>> vit
>> are DSCP it would become 10101100 and it needs to be 1011100.
>>
>> The thing is that there will be a 0 appended and prepended so it becomen
>> 01011100
>> My question is why is the 0 perpended in front of the bits?
>> 11000 is 24 if the six most significant bits remain DSCP you need to
>> add 24
>> 101 11000
>>
>> Kind regards,
>>
>> Maarten Vervoorn
>> http://ccie.forumotion.com
>>
>>
>>
>> 2010/5/12 Beauty <fordownloadsccie_at_gmail.com>
>>
>> Hi Marten
>> >
>> > the confusion is in the syntax of the command .
>> >
>> > the set ip tos commands only allows you to set four bits in the TOS
>> > byte of the ip header
>> >
>> > by choosing a value of 12 you are setting minimum delay and maximum
>> > throughout
>> >
>> > so with the config you have above you will have EF , since IPP(3
>> > leftmost bits) is set to 5 or 101 in binary and delay and throughput
>> > bits are set while the remaining bits are clear (11000)
>> >
>> > Since dscp bits = 6 most significant bits or leftmost bits
>> >
>> > adding this up you have dscp EF(101110)
>> >
>> > see command refernce for more info on the set ip tos command
>> >
>> >
>> http://www.cisco.com/en/US/docs/ios/qos/command/reference/qos_s1.html#wp
>> 1059575
>> >
>> > HTH
>> >
>> >
>> > On 5/12/10, Maarten Vervoorn <mr.vervoorn_at_gmail.com> wrote:
>> > > I have a question about the solution a QoS excersise
>> > >
>> > > Requirement - Router originated telnet traffic should have
>> a
>> > dscp
>> > > of EF. Give the neccessary config.
>> > >
>> > > Restrictions:
>> > > Do this without using any interface commands
>> > > Do not use the command -> ip telnet tos xxx
>> > >
>> > > The solution to this is:
>> > > !
>> > > access-list 101 permit tcp any any eq telnet
>> > > !
>> > > route-map telnet permit 10
>> > > match ip address 101
>> > > set ip precedence 5
>> > > set ip tos 12
>> > > !
>> > > ip local policy route-map telnet
>> > >
>> > > Can you explain the TOS bit numbering for me? If i check the
>> > configuration
>> > > you are able to select tos 0-15.
>> > >
>> > > What I thought is that TOS is 128 bits (8 caracters). Left 3 are
>> > Precedence
>> > > and left 6 are DSCP
>> > > precedence 5 is 101 00000
>> > > DSCP ef is 101110 00
>> > > So if you need to add 00011000 to 1010000 to make 10111000
>> > > if I calculate 00011000 it is 24
>> > > What I understood from a previous post is that a 0 is appended and
>> > prepended
>> > > so this maken 01011100. But why is in this case the 0 prepended in
>> front
>> > of
>> > > the bits. Normaly DSCP are the left six bits. Now for all of a
>> sudden in
>> > a
>> > > route-map the DSCP bits are 7,6,5,4,3,2
>> > > Normaly when you calculate Precedence or DSCP in TOS yoi take bits
>> 8,7,6
>> > for
>> > > precedence and 8,7,6,5,4,3 for DSCP
>> > > Precedence 5 = TOS 160
>> > >
>> > >
>> > > Blogs and organic groups at http://www.ccie.net
>> > >
>> > >
>> _______________________________________________________________________
>> > > Subscription information may be found at:
>> > > http://www.groupstudy.com/list/CCIELab.html
>> > >
>> > >
>> > >
>> > >
>> > >
>> > >
>> > >
>> > >
>> >
>> >
>> > --
>> > Warm Regards ,
>> > Beauty
>>
>>
>> Blogs and organic groups at http://www.ccie.net
>>
>> _______________________________________________________________________
>> Subscription information may be found at:
>> http://www.groupstudy.com/list/CCIELab.html

Blogs and organic groups at http://www.ccie.net
Received on Wed May 12 2010 - 22:05:30 ART