Drag and Drop Questions

hi! can anybody explain this two below… im confuse:

Marking —> packet differentiation? answer. Marking — tail drop?
Shaping —> tail drop? answer: Shaping– packet differentiation?

Marking —- Tail drop is the default drop mechanism.
Shaping —- prevents the bit rate of the packets exiting an interface from exceeding a configured shaping rate….. packet differentiation?

I think RED should be connected with Tail Drop. RED provide a machisme to avoid tail drop.

I think Marking and Classification are mixed. You always Mark your traffic ‘near the edge of the network’ yet ALL policy maps rely on classification be it classifying traffic that has already been marked BY a device at the edge of the network or classifying traffic via NBAR or ACL so you can Mark it ON a device at the edge of the network

So….I believe it should be:

Classification —> packet differentiation
Marking ———-> near the edge of the network.

Jason – although you are correct that WRED does provide a mechanism to avoid tail drops, a better choice for WRED is ‘drop packet’ as this option doesn’t go well with any other item in the list. In addition, although the object of WRED is to prevent tail drop, you will experience taildrop in a queue if it gets full.

Though it is mentioned as -> Classification & Marking.But in real it is Marking & Classification.

You Mark the packets that needs to be Classified.

I think the correct answers are :

Classification —> near the edge network
Queuing —> congestion management
Marking —> packet differentiation
RED —> tail drop
Shaping —>inbound interface
Policing —>drop packets

explanation :

For classification—On ingress only, and only if the interface supports that particular header
field
For marking—On egress only, and only if the interface supports that particular header field

Tail drop is a mechanism of RED.

If the configured rate is exceeded, the shaper delays packets, holding the packets in a shaping queue.So shaping does not drop the packet , but policing does.

@Josh6226.

Shaping can not be configured on the inbound interface so you’re answer can’t be correct.

Policing and dropping. Yes it can be associated this way but policing can remark and also allows traffic through even though it exceeds or violates part of the traffic contract. The dropping fits a whole lot better with RED as that’s the whole point of it i.e. D stands for Dropping. I nearly made the same mistake.

@DBurger

I think it’s the other way around. You can’t actually mark traffic until it’s been classified by some ACL, failure to meet a traffic contract etc. except in certain circumstances i.e. Adaptive Shaping with BECN etc. so the better answer is…

Classification —> near the edge network
Queuing ——–> congestion management
Marking ——–> packet differentiation
RED ————-> drop packets
Shaping ——–>tail drop
Policing ———>inbound interface

Which match rstut’s view.

With Marking being packet differentiation as it’s only with the DSCP type options that you get granularity.

I suspect that with the amount of overlap between the options there’s more than one version of the answer.

RED — > Tail drop

P536 — CCIE R&S edit 2009

When a queue is full, IOS has no place to put newly arriving packets, so it discards them. This phenomenon is called tail drop.

@Benson Lei

Tail drop happens to any queue that gets full.

so many comments and books, which is the correct answer ?

Hey Guys,

I developed a SWF file for this DnD:

Download ZIP / UnZip and run quiz.html …..enjoy 🙂

http://www.4shared.com/file/nOwX0ZwZ/Drag_n_Drop.html

quiz.html
quiz.swf

100% agree with Rstut on Question 1:

Answer:

Classification —> near the edge network
Queuing —> congestion management
Marking —> packet differentiation
RED —> drop packets
Shaping —> tail drop
Policing —> inbound interface

Just to share an “official” explanation on Shaping and Policing

http://www.cisco.com/en/US/tech/tk543/tk545/technologies_tech_note09186a00800a3a25.shtml

Marking —> near the edge network
Queuing —> congestion management
Classification —> packet differentiation
Shaping —> drop packets
RED —> tail drop
Policing —> inbound interface

is this the right answer?

Marking —> near the edge network
Queuing —> congestion management
Classification —> packet differentiation
Shaping —> drop packets
RED —> tail drop
Policing —> inbound interface

Hi friends

Some friend are posting here Drag N drop was changed , some words are changed , what is new drag n drop and answers ?

Is it correct words of Drag & Drop ?

Marking —> near the edge network
Queuing —> congestion management
Classification —> packet differentiation
Shaping —> drop packets
RED —> tail drop
Policing —> inbound interface

What is new words of drag & drop ,someone post earlier in this form ? ( explanations in the right side are different.)

Anyone can Explain ?

Which answer is correct ?

1 –

Classification —> near the edge network
Queuing —> congestion management
Marking —> packet differentiation
RED —> drop packets
Shaping —> tail drop
Policing —> inbound interface

or

2 –

Marking —> near the edge network
Queuing —> congestion management
Classification —> packet differentiation
Shaping —> drop packets
RED —> tail drop
Policing —> inbound interface

after having read a lot of material — traffic shaping is used to shape the traffic under a criterion ( not drop the traffic ) and delay the traffic until bandwidth is available again..

Just clear the CCIE written over this weekend

DnD is similar but more difficult…the wording is not a simple word again, but a sentence…
do please fully understand the full meaning…not just hard push in your mind.

Policing —> paket drop
Shaping —> tail drop
RED —> packet differentiation
Queuing —> congestion management
Marking —> near the edge
Classification —> inbound interface

I got 1000/1000

My Drag N Drop Answer is

Classification —>>> At the access layer
Queuing —>>> Congestion management
Marking —>>> Packet differentiation
RED —>>>Discovered to alleviate tail drop
Shaping —>>>Blocked on applying to inbound interface
Policing —>>> Drop excess traffic

Hi zain and sanjana

Could u please help me to understand the 4sim.Still i have a confusion on that.

Thanks and Regards
Padmini

Is it correct words of Drag & Drop ?

Marking —> near the edge network
Queuing —> congestion management
Classification —> packet differentiation
Shaping —> drop packets
RED —> tail drop
Policing —> inbound interface

What is new words of drag & drop ,someone post earlier in this form ? ( explanations in the right side are different.)

Anyone can Explain ?

I got 1000/1000 ,too

Is this the correct answer

Marking —> near the edge network
Queuing —> congestion management
Classification —> packet differentiation
Shaping —> drop packets
RED —> tail drop
Policing —> inbound interface

Mrs Sanjana chopra,

You got 1000/1000 but we are discus here another D&D. If you know the right answer of following D&D so tell us what is right?

Classification —> near the edge network
Queuing ——–> congestion management
Marking ——–> packet differentiation
RED ————-> drop packets
Shaping ——–>tail drop
Policing ———>inbound interface

Marking —> near the edge network
Queuing —> congestion management
Classification —> packet differentiation
Shaping —> drop packets
RED —> tail drop
Policing —> inbound interface

Marking —> near the edge network
Shaping —> congestion management
Classification —> packet differentiation
Policing —> drop packets
RED —> tail drop
Queuing —> inbound interface

Can anyone tell me about sim? In the sim will be provide console for run command? Or just need the select answer?

RED is Drop packet. You can go to wiki to check the answer.
RED drop the packet before tail drop happened.

Sanjana Chopra …. How did you get 1000 point? 😀

– Classification: The process used to select the traffic to be marked.
so that it must be at Access-layer.
-Marking: It should be at DS-Layer (Layer 3)or it can implement at Access-Layer (layer2)

Rstut is correct

Shaping can apply on the outbound interfact only. Policing can apply inbound/outbout.
so that policing >> inbound (correct)
Shaping: keep the packet to the queue when the traffic over rate limit. Over rate packets will keep in the queue when the queue is full. The tail drop will happen…

I passed in CCIE Written today (09/29/11) with 976

This question, the correct answer is

Classification —>>> At the access layer
Queuing —>>> Congestion management
Marking —>>> Packet differentiation
RED —>>>Discovered to alleviate tail drop
Shaping —>>>Blocked on applying to inbound interface
Policing —>>> Drop excess traffic

Umm, are you really just giivng this info out for nothing?

i took the exam and i fail with 650 🙁 very bad score .. i forget every thing and i didnt study well .. but im gonna try again in 2 month !!!

i agree with rstut solution and here my reasons:
1- let us match the choices whisch we all agree upon:
Classification —> near the edge network
Queuing —>>> Congestion management
Marking —> packet differentiation
note Cisco defines Queueing as congestion management, and defines Policing and shaping as traffic regulation.

2- we have now 3 choices, let begin us with policing:
drop packets is not policing behvior, policing drop exccess traffic.
so we have 2 choices that could match policing, but tail drop won’t fit here because it is a general QOS behaviour so it is unlikely to be chosen, because there is another more specific choice which is inbound interface, so my choice would be:
Policing ———>inbound interface

3- now we look at RED:
again tail drop won’t fit here because it is a general QOS behaviour so it is unlikely to be chosen because there is another more specific choice which is Drop Packet, and Drop Packets is the RED main function, so my choice would be:
RED ————-> drop packets

4- now we are left with the only choice, which is:
Shaping ——–>tail drop
and this will fit because when a shaping queue is full, it will begin tail drop.

as you know the answer is wrong please correct it.

mrk
i wrote the comment on the 27th of Novemebr
do you mean that my answer is wrong, if yes state your reasons

I agree with you, Fabio.

I think correct answer must be this:

Classification —> At the access layer
Queuing —> Congestion management
Marking —> Packet differentiation
RED —> Discovered to alleviate tail drop
Shaping —> Blocked on applying to inbound interface
Policing —> Drop excess traffic

This came up for me in Nov 2009 but the Pink options were:
NOT ON AN Inbound I/F **
Discards excess traffic
Differentiation of packets
Congestion Management
AVOIDS THE Tail Drop effect **
Implemented at the Access Layer

The two with ** are the opposite to RStut

I’m sitting this again tomorrow so if it comes up I’ll report back.

to clear up classfication vs marking

http://www.cisco.com/en/US/technologies/tk543/tk766/technologies_white_paper09186a00800a3e2f_ps6610_Products_White_Paper.html –> see figure 5. Traffic Conditioner Block (TCB)

Classification is selecting. it’s a capability of indentification in order to differ packets. access list, seeing ip prec or dscp bit set in the packet, match are tools for classification. Marking is writing or rewriting packets (let say, don’t trus the original dscp) or choose not to drop packets but giving it dscp value for another classification at next hop router. deploying ip prec and dscp bit in packet is doing marking.

classification and marking should be performed as close to the edge of the network as possible. and i think classification and marking are both used for packet differentiation.

hey then: marking is done by client device near the edge network before classification? could be true. Traffic classifiers may honor any DiffServ markings in received packets or may elect to ignore or override those markings. But, it is very rare that the network honors markings at the ingress to the DiffServ domain. So, what actually happens is the network doing traffic classfication based on: access list (source dest ip, protocol,etc),or just trust ip prec/dscp and assign them to separate class. Based on marking in each separate class, we apply policy (shaper/dropper or rewrite) on egress.

i agree with rstut answer:
Classification —> near the edge network
Queuing —> congestion management
Marking —> packet differentiation
RED —> drop packets
Shaping —> tail drop
Policing —> inbound interface

Jep: was was your answer for this question in the exam…
Plz share us ..

@Nikhil, i see in other page you had overcome ccie written;-) congrats. lets prepare for LAB.

I guess I will go with the answer that most agree on and RSTUT gives but I would have swapped classification and marking around since:

Although marking without classifying is almost useless (except when implicitly using source interface to classify) marking needs to be done once near the edge.

Classification and packet differentiation are done both when classifying and marking at the edge, and at all hops in network that use QoS congestion management tools, so I personally would think the best answer is:

Marking —> near the edge network (Marking should be done near edge and only once)
Queuing —> congestion management
Classification —> packet differentiation (true and at each QoS hop)
RED —> drop packets
Shaping —> tail drop
Policing —> inbound interface

Just another contentious question I guess

Good luck
Matt

This question, the correct answer is

Classification —>>> At the access layer
Queuing —>>> Congestion management
Marking —>>> Packet differentiation
RED —>>>Discovered to alleviate tail drop
Shaping —>>>Blocked on applying to inbound interface
Policing —>>> Drop excess traffic

So this question is not really as it’s asked at the top.
Looks like, real question is actually something like the Anonymous sent above.
Answers are logical with those as well. Case resolved.

HI All,

If the below is the answer and Question in Exam, I believe that is correct answer.

Classification —>>> At the access layer
Queuing —>>> Congestion management
Marking —>>> Packet differentiation
RED —>>>Discovered to alleviate tail drop
Shaping —>>>Blocked on applying to inbound interface
Policing —>>> Drop excess traffic

If the answer and Question is same like this forum, I think its very confusing.
I think below is the most closer answer but I believe sometime the correct answer
might wrong in exam.

The Tail drop is actually on RED, WRED and FIFO, but all are under congestion avoid management, that why the answer and Question is very confusing.

Policing —> Drop packets – Quite sure
RED —> Tail drop – Quite sure
Queuing —> congestion management
Marking —> packet differentiation

The most possible answer
Classification —> inbound interface ( should apply to inbound and outbound traffic )
Shaping —> near the edge network

Hi Fabio Teixeira

Appreciate if you could confirm the Question and Answer that you post is actualty the one come out in the Exam and not the one in this forum. Thank

Hey Guys. The current DnD question inclusive the correct answer can be found in Spike’s latest dump (confirmed to be valid by many users) via: http://www.examcollection.com/cisco/Cisco.Pass4sure.350-001.v2012-01-31.by.Spike.208q.vce.file.html
Sanjanas dump which has also been confirmed as valid shows the same DnD question and solution. It can be found here: http://www.examcollection.com/cisco/Cisco.ActualTest.350-001.v2011-08-01.by.SanjanaChopra.156q.vce.file.html