Re: cos rewriting on switch

* *

* May be this will help:*

**

*` TOS Byte **_*

*IPP*

*IPP*

*IPP*

*D*

*T*

*R*

*ECN*

*ECN*

*Decimal*

*IPP Level*

*TOS Levels*

*0*

*0*

*0*

*0*

*0*

*0*

*0*

*0*

*0*

*0*

*0  31*

*0*

*0*

*1*

*0*

*0*

*0*

*0*

*0*

*32*

*1*

*32  63*

*0*

*1*

*0*

*0*

*0*

*0*

*0*

*0*

*64*

*2*

*64  95*

*0*

*1*

*1*

*0*

*0*

*0*

*0*

*0*

*96*

*3*

*96  127*

*1*

*0*

*0*

*0*

*0*

*0*

*0*

*0*

*128*

*4*

*128  159*

*1*

*0*

*1*

*0*

*0*

*0*

*0*

*0*

*160*

*5*

*160  191*

*1*

*1*

*0*

*0*

*0*

*0*

*0*

*0*

*192*

*6*

*192  223*

*1*

*1*

*1*

*0*

*0*

*0*

*0*

*0*

*224*

*7*

*224 - 255*

* *

On Wed, Nov 10, 2010 at 9:04 AM, Jack Router <pan.router_at_gmail.com> wrote:

> Thanks Mark. You pointed me to the right direction to undestand this.
>
> Just a question: why you used value "101111000" for the ping test? All that
> counts are first three bits 101, decimal 5. The rest of the TOS byte can be
> anything. I just did extended ping from R2 with Type of service 160, 170
> and
> 191 (all tose numbers begin 101 in binary) and it is received on R1 as
> cos5,
> as expected. Does it make sense ?
>
>
> On 10 November 2010 10:50, <mwcombs_at_comcast.net> wrote:
>
> > Jack,
> >
> >
> >
> > I specified in my previous email that you have to mark your service class
> > 184 on your ping tests. I meant TOS (type of service) not to be confused
> > with dscp values.
> >
> >
> >
> > TOS values:
> >
> > binary 101110, the full TOS value is 101111000 which is decimal 184, or
> in
> > hex 0xB8.
> >
> > - Mark
> >
> > ----- Original Message -----
> > From: mwcombs_at_comcast.net
> > To: "Jack Router" <pan.router_at_gmail.com>
> > Cc: ccielab_at_groupstudy.com
> > Sent: Wednesday, November 10, 2010 9:30:45 AM
> > Subject: Re: cos rewriting on switch
> >
> > Jack,
> >
> >
> >
> > Your traffic leaving R2 must mark it's traffic with cos5 or 0x2e in hex
> > which
> > equates to an precedence 5.B Is your router2 even marking your traffic
> > properly?B I would setup a monitoring port on port 2 which connects to
> > router
> > 2 to validate the packets coming in are indeed marked properly.B My
> guess
> >
> > they are not.
> >
> >
> >
> > Another thought is why are you trying to look for a greated cos value
> then
> > 0
> > on an ICMP packet?B When you do your pings are you using extended
> options
> > commands and specifing service class 184?B You will need to do this if
> you
> > want to mark your packet with cos vaule of 5.B If not your pings will
> just
> > be
> >
> > normal pings.
> >
> >
> >
> > - Mark Combs
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > ----- Original Message -----
> > From: "Jack Router" <pan.router_at_gmail.com>
> > To: ccielab_at_groupstudy.com
> > Sent: Tuesday, November 9, 2010 10:31:18 PM
> > Subject: cos rewriting on switch
> >
> > Hello all,
> >
> > I have a question about cos rewriting on a switch. Here is scenario:
> >
> > R1(f0/0.100)-----dot1q------(f0/1)SW1(f0/2)------access-------(f0/0)R2
> >
> > On R1 I configured class maps and policy map to identify what cos is
> > received.
> > SW1 has NO mls qos enabled or any cos configuration.
> >
> > When I ping R1 from R2 i see that R1 receives packets marked with cos0.
> Why
> > ? Packets that leave R2 are not tagged with cos value, why then R1
> receives
> > packets cos0 ?
> > Is cos0 a synonym of no cos marking ?
> >
> >
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>
>
>
>
>
>
>

--
*Narbik Kocharians
*CCSI#30832, CCIE# 12410 (R&S, SP, Security)
www.MicronicsTraining.com <http://www.micronicstraining.com/>
Sr. Technical Instructor
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