[c-nsp] 7200 DSCP-to-EXP Mapping

[ar]

Thanks for this info.

Though I thought during the POP hop, top label will be copied to the bottom label for Uniform,short pipe mode? is this right?

--- On Mon, 9/19/11, Vitkovsky, Adam <avitkovsky at emea.att.com> wrote:

From: Vitkovsky, Adam <avitkovsky at emea.att.com>
Subject: RE: [c-nsp] 7200 DSCP-to-EXP Mapping
To: "ar" <ar_djp at yahoo.com>
Cc: "cisco-nsp at puck.nether.net" <cisco-nsp at puck.nether.net>
Date: Monday, September 19, 2011, 9:11 PM




 
 

 







 



Yes please during the swap operation the
exp value of the incoming label is automatically used with the outgoing label 

However during the pop operation the incoming
label and it’s exp value is lost and packet is dispatched with whatever
remaining labels in the stack 

   

So either you make sure that at the ingress
PE -during the label imposition the exp value has been set accordingly on all the
labels in the stack (usually NH-label and VPN-label) 

-this way even though the topmost label
and it’s exp marking is lost during the POP operation 

 the remaining label carries the same
exp value as the top most one  –so you can use it to schedule the
packet accordingly 

   

Or on each penultimate hop node you
manually copy the exp value of the top-most label that is going to be discarded
during the POP operation and use it to set the newly exposed label’s exp
value  

  

   



adam 



   









From: ar
[mailto:ar_djp at yahoo.com] 

Sent: Monday, September 19, 2011
2:40 PM

To: Vitkovsky, Adam

Cc: cisco-nsp at puck.nether.net

Subject: Re: [c-nsp] 7200
DSCP-to-EXP Mapping 



   


 
  
  I believe as the packet travels the MPLS domain,
  same EXP bits are applied as they swap top labels..this means I can always
  match on the same exp bit as it was mapped at the ingress PE. Do I still need
  the qos-groups in this case?

  

  

  

  --- On Mon, 9/19/11, Vitkovsky, Adam <avitkovsky at emea.att.com>
  wrote: 
  

  From: Vitkovsky, Adam <avitkovsky at emea.att.com>

  Subject: Re: [c-nsp] 7200 DSCP-to-EXP Mapping

  To: "Oliver Boehmer (oboehmer)" <oboehmer at cisco.com>, "
 cisco-nsp at puck.nether.net " <
 cisco-nsp at puck.nether.net >

  Date: Monday, September 19, 2011, 8:13 PM 
  
  Speaking of pipe modes :)

  

  I also failed to use the pipe mode with 12.2.33 SR codes

  As I was not able to use the qos-groups to keep track of the EXP value on the
  egress PE

  So on 7200s I pretty much got stuck with a short pipe mode and "set
  mpls-exp imposition" at the ingress PE 

  

  adam

  -----Original Message-----

  From: cisco-nsp-bounces at puck.nether.net
  [mailto:cisco-nsp-bounces at puck.nether.net]
  On Behalf Of Oliver Boehmer (oboehmer)

  Sent: Monday, September 19, 2011 1:43 PM

  To: cisco-nsp at puck.nether.net

  Subject: Re: [c-nsp] 7200 DSCP-to-EXP Mapping

  

  

  > >

  > > > I don't think there is in alternative to "set dscp

  > > > default" on ingress policy-maps to effectively remark

  > > > ingress traffic on an edge-LSR device.

  > >

  > > Not sure what you mean - as in you don't think we can mark

  > > anything other than 'default' on ingress?

  > 

  > 'course not, sorry.. I meant to replace "default" by
  "<value>" before

  > sending, but forgot :-|

  

  and before someone argues: the above is obviously not relevant when

  using pipe/short-pipe mode, then you do NOT want to touch the ingress

  DSCP at all...

  

      oli

  

  

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