From: Pavel Bykov (slidersv@gmail.com)
Date: Sun Dec 07 2008 - 02:55:46 ARST
Mahmoud, this really is not correct, as you can see in the tests I have done
to prove Cisco documentation wrong.
max-reserved-bandwidth command does not influence policy maps in any way
other than configuration
Please see the following document:
http://www.boxoid.org/cisco/MAX-RESERVED-BANDWIDTH-AND-CBWFQ.pdf
On Sat, Dec 6, 2008 at 5:13 AM, mahmoud genidy <ccie.mahmoud@gmail.com>wrote:
>
> - The bandwidth reservation using percent in MQC is absolute with IOS 12.4
> - By default bandwidth reservation is up to %75 percent. The other %25 is
> to support best-effort and control traffic, and Layer 2 overhead.
>
> Based on that information it is now clear that:
>
> - If we need to reserve more than %75 of the interface bandwidth for
> different traffic classes then we have to use [ maximum-reservation
> bandwidth ] command to change the percentage.
>
> - For default class if left as it is then it will be best effort. And it
> will share bandwidth remaining from other classes with the layer-2 overhead
> and control traffic.
>
> So the answer for the question sent is:
>
> First we have to use: maximum-reserved bandwidth 100
>
> Second under class default we have to use: bandwidth percent 10
>
> This is my understanding so far. Please correct me if you think I'm wrong.
>
> Thanks,
> Mahmoud.
>
>
> On Fri, Dec 5, 2008 at 2:23 PM, mahmoud genidy <ccie.mahmoud@gmail.com>wrote:
>
>>
>> I agree with you if you will go with (map-class and traffic shaping)
>> option you will have to statically define CIR and MINCIR as well.
>>
>> But the point is based on what the question says I think we don't have to
>> configure shaping or map-class. We can directly assign the service policy to
>> the interface.
>>
>>
>>
>> On Fri, Dec 5, 2008 at 1:20 PM, Nick Matthews <matthn@gmail.com> wrote:
>>
>>> From what I understand of frame QoS in this situation -
>>>
>>> If you're using a map-class with a service policy (but not using
>>> interface-level frame-relay traffic shaping) you will need to assign the
>>> bandwidth level via cir/mincir or a hierarchical shaping policy. I noticed
>>> that doing 'show policy-map interface' will not show anything until one of
>>> these is configured.
>>>
>>> Feel free to correct if this isn't right.
>>>
>>>
>>> -Nick
>>>
>>>
>>> On Thu, Dec 4, 2008 at 7:52 PM, Pavel Bykov <slidersv@gmail.com> wrote:
>>>
>>>> Regarding #4: bandwidth is not reserved by default for class-default and
>>>> it
>>>> can easily starve. To really alocate bandwidth to class-default so it
>>>> has
>>>> minimum guarantee you'd need to use "bandwidth" command.
>>>>
>>>> On Fri, Dec 5, 2008 at 1:44 AM, mahmoud genidy <ccie.mahmoud@gmail.com
>>>> >wrote:
>>>>
>>>> >
>>>> > 1- For [ Critical voice ] wording. Is it a proctor question to ask if
>>>> he it
>>>> > requires matching precedence 5 in the ACL used to match the voice
>>>> traffic?
>>>> >
>>>> > 2- Again is it a proctor question if I like to confirm if [ maximum
>>>> > reserved bandwidth 100 ] is required or not?
>>>> >
>>>> > 4- Regarding the class-default as the question says remaining
>>>> bandwidth
>>>> > will go for the default class. This is the default behavior any way so
>>>> I
>>>> > think no extra configuration is required for it.
>>>> >
>>>> >
>>>> >
>>>> > On Fri, Dec 5, 2008 at 3:33 AM, Pavel Bykov <slidersv@gmail.com>
>>>> wrote:
>>>> >
>>>> >> Here is my take:
>>>> >> 1. I'd match udp port ranges AND precedence 5 to be sure. Maybe even
>>>> mark
>>>> >> it as critical on input, depending on context of other QoS tasks.
>>>> >> 2. It does not imply that, but it does seem logical in this example,
>>>> since
>>>> >> he asks you to allocate "remaining bandwidth" to default, which would
>>>> be the
>>>> >> rest of the interface bandwidth
>>>> >> 3. Interface
>>>> >> 4. It is NOT POSSIBLE to configure fair-queue if you put bandwidth
>>>> >> reservation. In this case, you are asked to reserve the res to class
>>>> >> default, so you would go:
>>>> >> class class-default
>>>> >> bandwidth percent 10
>>>> >>
>>>> >> So you will not be able to put fair queue in there.
>>>> >>
>>>> >>
>>>> >> On Thu, Dec 4, 2008 at 3:16 PM, mahmoud genidy <
>>>> ccie.mahmoud@gmail.com>wrote:
>>>> >>
>>>> >>> Hi
>>>> >>>
>>>> >>> I have a QoS scenario over FR link and I'm not sure which way should
>>>> I
>>>> >>> go.
>>>> >>>
>>>> >>> The case is as follows.
>>>> >>>
>>>> >>> A Router *R1* with S0/0 configured with FR with two PVC on main
>>>> interface
>>>> >>> (HUB). It is connected with two other routers R2 & R3 over FR as
>>>> spokes.
>>>> >>>
>>>> >>> The question says: On *R1* Allocate bandwidth as follows:
>>>> >>>
>>>> >>> - % 25 of S0/0 bandwidth for network 10.1.1.0/24
>>>> >>> - % 35 of S0/0 bandwidth for network 10.1.2.0/24
>>>> >>> - % 30 of S0/0 bandwidth for CRITICAL voice traffic
>>>> >>> - Remaining bandwidth is for Class-Default
>>>> >>>
>>>> >>> My questions are:
>>>> >>>
>>>> >>> - When he says *CRITICAL* voice does this mean in the extended ACL
>>>> to use
>>>> >>> precedence 5, or it is not necessary as Voice by default is critical
>>>> >>> traffic?
>>>> >>>
>>>> >>> - When he says for example %25 *OF S0/0* does this implies we have
>>>> to
>>>> >>> configure [ maximum-reserved-bandwidth 100 ] ?
>>>> >>>
>>>> >>> - The interface in question is FR with two PVCs. Does this mean we
>>>> have
>>>> >>> to
>>>> >>> apply the service policy through a FR MAP-CLASS with CIR equals S0?)
>>>> >>> bandwidth? Or we can directly apply the service policy on the serial
>>>> >>> interface?
>>>> >>>
>>>> >>> - Is it preffered to configure fair-queue for class-default in this
>>>> case,
>>>> >>> or
>>>> >>> just leave it as it is?
>>>> >>>
>>>> >>> Thanks in advance for your time.
>>>> >>>
>>>> >>> Mahmoud
>>>> >>>
>>>> >>>
>>>> >>> Blogs and organic groups at http://www.ccie.net
>>>> >>>
>>>> >>>
>>>> _______________________________________________________________________
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>>>> >>>
>>>> >>>
>>>> >>>
>>>> >>>
>>>> >>>
>>>> >>>
>>>> >>>
>>>> >>>
>>>> >>
>>>> >>
>>>> >> --
>>>> >> Pavel Bykov
>>>> >> ----------------
>>>> >> Don't forget to help stopping the braindumps, use of which reduces
>>>> value
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>>>> >>
>>>> >
>>>> >
>>>>
>>>>
>>>> --
>>>> Pavel Bykov
>>>> ----------------
>>>> Don't forget to help stopping the braindumps, use of which reduces value
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>>>>
>>>>
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>>>>
>>>> _______________________________________________________________________
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>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>
>>
>
-- Pavel Bykov ---------------- Don't forget to help stopping the braindumps, use of which reduces value of your certifications. Sign the petition at http://www.stopbraindumps.com/Blogs and organic groups at http://www.ccie.net
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