Edward, not every organization or network will treat DSCP values the same. That is why you can have a DSCP-DSCP translation table the domain border. CoS is layer 2, DSCP is layer 3.
On Wed, Aug 19, 2009 at 12:41 PM, Bodnar, Edward <[email protected]>wrote: > So this brings me back to when to use CoS or when to use DSCP. Do I have > to use both? Can I use one over the other and when would I use DSCP vs > CoS. > > > > *From:* prakash patel [mailto:[email protected]] > *Sent:* Wednesday, August 19, 2009 2:38 PM > > *To:* Bodnar, Edward; [email protected] > *Subject:* RE: [OSL | CCIE_RS] QOS question > > > > Everything is about changing the default. > > Yes in some cases , you do like to bypass the mapping of COS-DSCP..and > trust DSCP. > > In some case you like to change the DSCP if device is marking with DSCP > > In some cases you changed it based on COS if device is not marking DSCP. > > > > > > ------------------------------ > > From: [email protected] > To: [email protected]; [email protected] > Date: Wed, 19 Aug 2009 13:32:45 -0500 > Subject: RE: [OSL | CCIE_RS] QOS question > > I would think you would still need to do a DSCP to CoS mapping then back to > DSCP. I am looking at some configuration and then seem to just pass the > DSCP mapping right through the switches. > > > > *From:* prakash patel [mailto:[email protected]] > *Sent:* Wednesday, August 19, 2009 2:28 PM > *To:* Bodnar, Edward; [email protected] > *Subject:* RE: [OSL | CCIE_RS] QOS question > > > > FOr internal schduling /queing > > > > ------------------------------ > > From: [email protected] > To: [email protected]; [email protected] > Date: Wed, 19 Aug 2009 13:15:57 -0500 > Subject: RE: [OSL | CCIE_RS] QOS question > > So any time I pass from a layer 2 device to a layer 3 device I need to > translate the CoS to DSCP. And any time I go from a layer 3 device to layer > 2 device I need to translate DSCP to CoS? If this is true then why do that > have DSCP to DSCP translations in switches ? > > > > *From:* prakash patel [mailto:[email protected]] > *Sent:* Wednesday, August 19, 2009 2:09 PM > *To:* Bodnar, Edward; [email protected] > *Subject:* RE: [OSL | CCIE_RS] QOS question > > > > Layer 2 devices connection ...USE COS > > LAYER 3 devices use DSCP. > > > > > > > > ------------------------------ > > From: [email protected] > To: [email protected] > Date: Wed, 19 Aug 2009 13:01:01 -0500 > Subject: [OSL | CCIE_RS] QOS question > > When would I use CoS over DSCP or DSCP over CoS. > > > ------------------------------ > > With Windows Live, you can organize, edit, and share your photos. Click > here. <http://www.windowslive.com/Desktop/PhotoGallery> > > > ------------------------------ > > Get back to school stuff for them and cashback for you. Try BingT > now.<http://www.bing.com/cashback?form=MSHYCB&publ=WLHMTAG&crea=TEXT_MSHYCB_BackToSchool_Cashback_BTSCashback_1x1> > > > ------------------------------ > > Get back to school stuff for them and cashback for you. Try BingT > now.<http://www.bing.com/cashback?form=MSHYCB&publ=WLHMTAG&crea=TEXT_MSHYCB_BackToSchool_Cashback_BTSCashback_1x1> > > _______________________________________________ > For more information regarding industry leading CCIE Lab training, please > visit www.ipexpert.com > > -- Bryan Bartik CCIE #23707 (R&S), CCNP Sr. Support Engineer - IPexpert, Inc. URL: http://www.IPexpert.com
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