From: David Duncon (david_ccie@hotmail.com)
Date: Thu Dec 30 2004 - 08:26:06 GMT-3
Certainly your detailed explanation helped me big time, Bob :-)
Though my Qs were not directly answered, with your explanation , at least
now I can relate list sequential events with in shaping and queuing.
Like Brian M's , your Qos threads are very well written and more importantly
touches the core concept of each feature we are talking about.
Cheers
- David.
>From: "Bob Sinclair" <bsin@cox.net>
>To: "David Duncon" <david_ccie@hotmail.com>,<ccielab@groupstudy.com>
>Subject: Re: Class class-default
>Date: Wed, 29 Dec 2004 10:55:16 -0500
>
>Hi David,
>
>These are all good questions you ask, and I hope some other folks will give
>us the benefit of their experience. Here are some conclusions I have
>reached that may be relevant:
>
>When frame-relay traffic-shaping is configured on a physical interface,
>the concept of interface Available Bandwidth disappears, and max-reservable
>bandwidth is equal to mincir of the dlcis.
>
>Notes below regard applying cbwfq policy-maps at different levels.
>
>On Physical Interfaces:
>
>
>Any policy-map can be applied to a physical interface using the
>service-policy input/output command.
>
>
>On Subinterfaces:
>
>
>Policies that use only the "shape," "set" or "police" options can be
>applied directly to a subinterface.
>
>
>Policy-maps that use the "bandwidth" or "priority" commands must be applied
>in a child policy to a shaped parent policy (a "nested" or "hierarchical"
>policy). Any "percent" value in the child policy is of the shaped rate.
>
>
>On DLCIs:
>
>
>Policy-maps cannot be applied directly to DLCIs. They must be applied in a
>Frame-Relay map-class.
>
>
>If Frame-Relay traffic shaping is configured on the physical interface,
>then any policy can be applied directly to a map-class.
>
>
>If Frame-Relay traffic shaping is not configured on the physical interface,
>then policies that use only the "shape," "set" or "police" options can be
>applied directly to a map-class.
>
>
>Policy-maps that use the "bandwidth" or "priority" commands must be applied
>in a child policy to a shaped class-default in the parent policy (a
>"nested" or "hierarchical" policy). Any "percent" value in the child policy
>is of the shaped rate.
>
>Above comments are not directly on point. But hope they help.
>
>Bob Sinclair
>CCIE #10427, CCSI 30427, CISSP
>www.netmasterclass.net
>
>----- Original Message ----- From: "David Duncon" <david_ccie@hotmail.com>
>To: <bsin@cox.net>; <ccielab@groupstudy.com>
>Sent: Wednesday, December 29, 2004 6:25 AM
>Subject: Re: Class class-default
>
>
>>Ok, now I know where you are coming from , Bob :-) Thanks.
>>
>>Can I ask you one last Q before we exit this topic ?
>>
>>I am not 100% on this max-reference bandwidth command's functionality.
>>From my understanding MQC is by default is only uses 75% of the target CIR
>>of the circuit. And if you want to use MQC engine to use more than 75% of
>>the available CIR , then you use this max-reference bandwidth command to
>>tweak this behavior.
>>
>>Now let me take help of an example to push my doubts across.
>>
>>So let us say we have a P2P VC an Access & CIR of 1024k and 256k
>>respectively. And I have configured " Access of 1024k " on the serial
>>interface with a "bandwidth command. But at L2 I have , I have adaptive
>>shaping becn (with mincir of 257000) and throttle down to the real CIR of
>>256k in the event of congestion.
>>
>>Now these are my doubts,
>>
>>1) I was in impression that Frame relay predominantly takes the mincir
>>value as the primary reference value , so unlike any other WAN protocols ,
>>we do not necessarily need to configure the max-reference bandwidth
>>command on the serial interfaces. Am I on right school of thought ?
>>
>>As a mater of fact , that is what I am running on my production network.
>>While running LLQ & CBWFQ at L3 and A/shaping at L2 , I am not using
>>this command at all on our frame circuits . And every things works as per
>>specs or user requirements. So I was wondering when do I need to use this
>>command on the ground.
>>
>>2) Secondly as I mentioned above , I normally configure the Access value
>>on each VC as my bandwidth command under serial int or sub interfaces at
>>both the ends. So I assume that Queuing engine will look at the Access
>>value of 1024k as the reference point (to take 75% of that ###) at L3 and
>>then A/Shaping engine will look at MINCIR value of 256k , then how does it
>>work. Do you see my confusion ?
>>
>>May be I am thinking too many unnecessary aspects or I am bit confused on
>>how L2 shaping config interacts with L3's Queuing before the actual 0s and
>>1s are clocked on to the wire.
>>
>>I appreciate your guidance on this long running & confused issue :(
>>
>>Cheers
>>
>>- David.
>>
>>>From: "Bob Sinclair" <bsin@cox.net>
>>>To: "David Duncon" <david_ccie@hotmail.com>,<ccielab@groupstudy.com>
>>>Subject: Re: Class class-default
>>>Date: Mon, 27 Dec 2004 22:32:55 -0500
>>>
>>>Hi David,
>>>
>>>When I reserve bandwidth for a class and apply that policy to an
>>>interface, I should see the Available Bandwidth parameter decrease from
>>>75% (default max-reservable). Each time I reserve more bandwidth in an
>>>applied policy I should see Available bandwidth (show interface)
>>>correspondingly decrease. This did not happen when I entered the command
>>>to reserve bandwidth for class class-default, further suggesting that the
>>>command is not effective.
>>>
>>>HTH,
>>>
>>>Bob Sinclair
>>>CCIE #10427, CCSI 30427, CISSP
>>>www.netmasterclass.net
>>>
>>>----- Original Message ----- From: "David Duncon"
>>><david_ccie@hotmail.com>
>>>To: <bsin@cox.net>; <ccielab@groupstudy.com>
>>>Sent: Monday, December 27, 2004 8:58 PM
>>>Subject: Re: Class class-default
>>>
>>>
>>>>Appreciate your feedback, Bob.
>>>>
>>>>As I did not quite get your point (attached clip bellow) , can you
>>>>please elaborate ?
>>>>
>>>><clip> it does not decrease available bandwidth on the interface. <clip>
>>>>
>>>>Cheers
>>>>
>>>>- David
>>>>
>>>>>From: "Bob Sinclair" <bsin@cox.net>
>>>>>To: "David Duncon" <david_ccie@hotmail.com>,<ccielab@groupstudy.com>
>>>>>Subject: Re: Class class-default
>>>>>Date: Mon, 27 Dec 2004 08:17:17 -0500
>>>>>
>>>>>David,
>>>>>
>>>>>I would say definitely option 1. Is the bandwidth command really
>>>>>effective in class class-default? On my box it takes the command, but
>>>>>it does not show up in the output of "show policy-map interface," and
>>>>>it does not decrease available bandwidth on the interface.
>>>>>
>>>>>HTH,
>>>>>
>>>>>Bob Sinclair
>>>>>CCIE #10427, CCSI 30427, CISSP
>>>>>www.netmasterclass.net
>>>>>
>>>>>----- Original Message ----- From: "David Duncon"
>>>>><david_ccie@hotmail.com>
>>>>>To: <ccielab@groupstudy.com>
>>>>>Sent: Monday, December 27, 2004 2:54 AM
>>>>>Subject: Class class-default
>>>>>
>>>>>
>>>>>>Hi Group,
>>>>>>
>>>>>>I got a Q on MQC 'c class class-default behavior. And appreciate your
>>>>>>guidance on this.
>>>>>>
>>>>>>On production network, let us consider that we have end to end L3 MQC
>>>>>>policy which primarily aimed to protect Business critical apps such
>>>>>>as Voice and Citrix and bundled every other traffic type such as File
>>>>>>transfers , HTTP and Emails ..etc in to a common default class with
>>>>>>random detect feature enabled. Since there is a bit of concern on the
>>>>>>email (MS Exchange & Lotus Notes Domino) traffic with in a default
>>>>>>class as we are seeing some drops there. So If we were to segregate &
>>>>>>prioritize email traffic from the rest of default class traffic ,
>>>>>>then which of the following options is the better way to go. Either to
>>>>>>leave the email traffic with in class class-default and assign a
>>>>>>guaranteed bandwidth or to segregate email traffic in to separate
>>>>>>class-map with in policy-map. The reason I am asking this Q is to
>>>>>>understand any negative impacts the NON time sensitive email traffic
>>>>>>can bring in to policy maps processing where already time sensitive
>>>>>>traffic types (Voice & citrix) are being serviced.
>>>>>>
>>>>>>
>>>>>>Option 1:
>>>>>>=================
>>>>>>
>>>>>>Policy-map data
>>>>>>
>>>>>>Class voice
>>>>>>Match access-group xxx
>>>>>>Priority xxx
>>>>>>
>>>>>>Class citrix
>>>>>>Match access-group xxx
>>>>>>Bandwidth xxx
>>>>>>
>>>>>>Class email
>>>>>>Match access-group xxx
>>>>>>Bandwidth xxx
>>>>>>
>>>>>>Class class-default
>>>>>>Random detect
>>>>>>
>>>>>>Option 2:
>>>>>>==================
>>>>>>
>>>>>>Policy-map data
>>>>>>
>>>>>>Class voice
>>>>>>Match access-group xxx
>>>>>>Priority xxx
>>>>>>
>>>>>>Class citrix
>>>>>>Match access-group xxx
>>>>>>Bandwidth xxx
>>>>>>
>>>>>>Class class-default
>>>>>>Random detect
>>>>>>Bandwidth xxx ---------------------------------------> emails are
>>>>>>bundled together along with file transfers & HTTP traffic with in
>>>>>>class default.
>>>>>>
>>>>>>
>>>>>>And my Qs are :
>>>>>>
>>>>>>1) is there any way where we can create 2 class-maps with in class
>>>>>>class-default , one for email and the rest for all default traffic ?
>>>>>>If yes is there any benefit in doing that ?
>>>>>>
>>>>>>2) or is it safe for me to create another class-map for email and slot
>>>>>>that in with policy-map itself along with voice & citrix and dedicate
>>>>>>certain amount of bandwidth to it.
>>>>>>
>>>>>>3) Thirdly , what is the between a class class-default with a
>>>>>>bandwidth command and one with out a bandwidth command. And also what
>>>>>>is the difference between a class class-default with a random detect
>>>>>>command and one with out it. Though I do aware the functionality of
>>>>>>congestion avoidance techniques such as WRED and RED , I was in the
>>>>>>impression that besides configuring random detect , you need to map it
>>>>>>to a relevant DSCP code which underlines a certain level of drop
>>>>>>probability. In other words, you are telling the policy engine on what
>>>>>>type of traffic you want her to drop should she pick up any early
>>>>>>congestion warnings.
>>>>>>
>>>>>>
>>>>>>Any feed back is much appreciated.
>>>>>>
>>>>>>- David.
>>>>>>
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>>>>>>_______________________________________________________________________
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>>>>>>
>>>>>
>>>>>
>>>>
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>>>
>>>
>>
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>
>
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