From: Tien (tientien.wang@gmail.com)
Date: Thu Nov 13 2008 - 19:34:15 ARST
Great discussion, I learn something new.
Thank You
On Thu, Nov 13, 2008 at 12:41 PM, Huan Pham <pnhuan@yahoo.com> wrote:
> Pavel,
>
> You're correct! Thanks for the correction. I did not notice that, even if I
> try to put class-default in front of other, it's automatically listed last.
> I
> was just discussing the general "oder of operation" in QoS using a MQC
> policy-map.
>
> Cheers,
>
> --- On Fri, 11/14/08, Pavel Bykov <slidersv@gmail.com> wrote:
>
> From: Pavel Bykov <slidersv@gmail.com>
> Subject: Re: FR-DE in class-map
> To: huan@huanlan.com
> Cc: "backbone systems" <backbone.systems@gmail.com>, "Cisco certification"
> <ccielab@groupstudy.com>
> Date: Friday, November 14, 2008, 6:30 AM
>
>
> Huan Pham, your statement would be true if the class was not class-default.
>
> "class-default" is a system class and cannot be deleted or put ahead of
> other
> classes.
> Also, it can never have a match statement - it will always match
> everything.
> This is easy to test - it can not be even created:
>
> Router(config)#class-map class-default
> % class-default is a well-known class and is not configurable under
> class-map
>
> Therefore having classes under it would not have any point. So you have to
> remember that "class-default" is an IMPLICIT class at the end, just like
> deny
> statement at the end of every ACL, prefix list and AS-PATH ACL, deny clause
> at
> the end of every in every route-map etc. But it does not deny all, it
> MATCHES
> ALL.
>
> P.S.: you can also create a class-map with "match any" statement that would
> match anything and therefore class-default would not receive any packets.
> But
> you still can never get rid of class-default.
>
> Note: all above is true for MQC
>
>
> On Thu, Nov 13, 2008 at 1:35 PM, Huan Pham <pnhuan@yahoo.com> wrote:
>
>
>
>
>
>
> Hi,
>
> Whenever a policy-map is binded to an interface, traffic leaving or comming
> to
> that interface (depending on the policy-map applied outbound or inbound)
> will
> be examined in the order of classes in which they are listed. Whenever
> traffic gets a positive match on a class, action takes place, then traffic
> will not be matched again the next class.
>
> In your case, class X will not be marked with DE. All other traffic will
> be
> marked.
>
> However, if you change the order of classes in your policy-map, i.e.
>
> policy-map X
>
> class class-default
> set fr-de
> class X
> ! no action
>
> then all traffic will be positively matched again class class-default, so
> ALL
> will be marked with DE, including traffic that normally matches class X
> itself.
>
> If you do "show policy-map interface" in this case, you wont see any
> traffic
> hitting class X at all.
>
> Whether getting marked with DE bit will be dropped before other traffic in
> the core is another story. If your Frame-Relay provider trust your marking
> and
> implements such a dropping policy, then the answer is YES.
>
> If they do not implement a dropping policy based on DE, then, all traffic
> is
> treated the same: John Chamber's or Level1 engineer's!
>
>
>
>
>
>
> On Thu, Nov 13, 2008 at 6:41 AM, backbone systems <
> backbone.systems@gmail.com> wrote:
>
> > For the following config,
> >
> > class-map X
> > match access-group 101
> >
> > policy-map X
> > class X
> >
> > class class-default
> > set fr-de
> >
> > map-class frame-relay Y
> > service-policy output X
> >
> >
> > int ser1/0
> > frame-relay interface-dlci 501
> > class Y
> >
> > Now my question is that wen it comes to droping of traffic ....the
> > traffic in the class-default is DE marked ...wat policy will be
> > followed for the traffic in "class X"...will it not be droped
> before
> > all the other traffic?For the class X there is not set statement..
> >
> > thanks
> >
> >
> > Blogs and organic groups at http://www.ccie.net
> >
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> >
> >
> >
> >
> >
> >
> >
>
>
> --
> Pavel Bykov
> -------------------------------------------------
> Stop the braindumps!
> http://www.stopbraindumps.com/
>
>
> Blogs and organic groups at http://www.ccie.net
>
> _______________________________________________________________________
> Subscription information may be found at:
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>
>
>
>
>
>
>
>
>
>
> --
> Pavel Bykov
> -------------------------------------------------
> Stop the braindumps!
> http://www.stopbraindumps.com/
>
>
> Blogs and organic groups at http://www.ccie.net
>
> _______________________________________________________________________
> Subscription information may be found at:
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