Thanks Dara for your addition. So I think that case you explained is known as the pipe-mode.. and of course the useage of the QOS-group will be very usefull in this case. but also I know another method to implement it which is the Explicit-null label where instead of poping the label on the penultimate device it's just swapped to a null " 0 " label to keep the Exp value of the topmost label. am I right ?
Thanks Ahmed On Tue, Jun 24, 2008 at 9:26 PM, dara tomar <[EMAIL PROTECTED]> wrote: > *Hi Ahmed, > > In addition to the to the points mentioned in other mails, for when and > where should we use the QOS-GRP id's. > > We specifically in an MPLS environment have to (necessarily ) use the > qos-grp id's, when the exp value on the labels are different and we have a > pop operation for the label, hence while queuing the packet on the exit > interface we cannot use the newly exposed MPLS EXP value, so what we do is > store temporarily the EXP value in the qos-grp id and make a decision in its > accordance on the exit interface.we sometime as well use it to propagate the > qos grp value to the EXP/Precedence to the newly exposed label on the exit > interface. > > In case of Internetworkexpert's lab it has been used many time > unnecessarily, may be just to make us learn!!! > > > Thanks, > Regards, > Dara* > > > On Tue, Jun 24, 2008 at 3:26 PM, ahmed mahmoud <[EMAIL PROTECTED]> > wrote: > >> Good day All. >> >> I have something to add here.. I understand the usage of the qos-groups >> but i don't understand why we need them?!! aren't the marking enough for >> traffic categorization ? like DSCP , IP-precedence or the mpls exp bits !!! >> . >> >> Ahmed >> >> On Tue, Jun 24, 2008 at 12:19 PM, JH Cockburn <[EMAIL PROTECTED]> >> wrote: >> >>> Hi M, >>> >>> >>> >>> Using qos-groups is not limited to PE routers only. In fact you may use >>> it anywhere where you think it can make life easier… >>> >>> >>> >>> >>> >>> So the idea is that you can match certain packets and mark them in a >>> certain qos-group and then later/elsewhere do stuff with the qos-group… >>> >>> >>> >>> For example match packets with a certain MPLS EXP COS value (on P router) >>> and set them to a qos-group and later maybe shape or apply WRED based on the >>> qos-group on another interface… >>> >>> >>> >>> >>> http://www.cisco.com/en/US/docs/ios/12_2t/12_2t13/feature/guide/ftenpkmk.html#wp1090481 >>> >>> >>> >>> >>> >>> May also be used in IPSEC Configs: >>> >>> >>> http://www.cisco.com/en/US/docs/ios/12_3t/12_3t8/feature/guide/gtqosips.html >>> >>> >>> >>> Hope this helps…. >>> >>> >>> >>> >>> ------------------------------ >>> >>> *From:* [EMAIL PROTECTED] [mailto: >>> [EMAIL PROTECTED] *On Behalf Of *mohamed hamed >>> *Sent:* Monday, June 23, 2008 10:36 PM >>> *To:* OSL CCIE Service Provider Lab Exam >>> *Subject:* [OSL | CCIE_SP] QoS group >>> >>> >>> >>> Hi everyone, >>> >>> >>> >>> Does anyone know where we should use the QoS group on P or PE Router? >>> >>> >>> >>> As I understand that we usually use it on PE router, but I found some >>> Labs on the internetwork expert use it on P router as well >>> >>> >>> >>> If anyone knows why we should use QoS grouo on P routers , please unicast >>> me a mail back >>> >>> >>> >>> *Mohamed Hamed* >>> >>> *Network Consulting Engineer*** >>> >>> *Mobile** (KSA-Riyadh): +966543464502* >>> >>> >>> >>> >>> >>> >>> >>> ------------------------------ >>> >>> Introducing Live Search cashback . It's search that pays you back! Try >>> it >>> Now<http://search.live.com/cashback/?&pkw=form=MIJAAF/publ=HMTGL/crea=introsrchcashback> >>> >> >> >
