From: kumara.shunmugam@wipro.com
Date: Wed Aug 10 2005 - 07:13:33 GMT-3
Excellent Chris... One of the GOOD Mail in QOS topic..
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of Chris Lewis (chrlewis)
Sent: Wednesday, August 10, 2005 2:50 AM
To: Edwards, Andrew M; Stefan Grey; ccielab@groupstudy.com
Subject: RE: GTS vs police cir vs FRTS
Hi,
There have been a couple of threads on this topic, so more detail is in
the archives, but here is my summary of the specific raised here.
Stefan, I think you need to compare the shape command in MQC and GTS,
not police cir, as shaping and policiing are clearly different
functions.
GTS can be configured on multiple interface encapsulation types
FRTS only on frame, but allows you to do per DLCI configurations
MQC seems to be widely misunderstood, in that it is only a CLI
mechanism, not a queuing mechanism of any kind. The idea behind
developing it was to create one way of configuring QoS via a unified CLI
on all IOS devices, regardless of the underlying queueing mechanisms,
for example MDRR, or MWRR. The relevance here is that there is a legacy
and an MQC way to apply GTS, legacy is with the traffic-shape interface
command, and MQC is by the shape command in the policy-map.
Some more info is here
http://www.cisco.com/en/US/products/sw/iosswrel/ps1834/products_feature_
guide09186a00800800fc.html
The solution to the specific question posted does not require a two rate
policer.
A two rate policer would be required if the question said sometihng like
allow 2.5M of 1250 byte packets, betweem 2.5M and 5M, remark 1250 byte
packets to DSCP 1, and above 7M, drop them. This would use the cir and
pir options of the police cir command. The police command is all that is
needed in this case, one would not use shaping as that would introduce
additional delay as the packest were queued as part of the shaping
function, and therefore would probably violate the question's
requirements.
Chris
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Edwards, Andrew M
Sent: Tuesday, August 09, 2005 10:53 AM
To: Stefan Grey; ccielab@groupstudy.com
Subject: RE: GTS vs police cir vs FRTS
Stefan,
The solution does not impart GTS or FRTS. It references a two rate
police schema by specifying either/or the CIR or PEAK.
The difference being CIR provides an average rate to police too, and
PEAK provides the maximum rate to police too (IOW, peak allows
bursting). Optionally you can set Bc and Be to specify the exact burst
values.
My question to GS is this:
Why would you use a two rate police scheme over a single rate police
scheme where IOS calculates Bc/Be, such as:
class-map match-any over1250
match packet length min 1250
policy-map police
class over1250
police 2500000 conform trans exceed drop
Int e0/1
Service in police
Service out police
Can someone please explain when one would be preferred over the other...
IOW, what wording would draw me to reach a two rate policing scheme?
andy
-----Original Message-----
From: Stefan Grey [mailto:examplebrain@hotmail.com]
Sent: Tuesday, August 09, 2005 5:04 AM
To: ccielab@groupstudy.com
Subject: GTS vs police cir vs FRTS
Could you please explain me the difference between this things ??
Task:
As an additional measure to decrease response time throughout your
network,
configure R5 so that packets over 1250 bytes are limited to 2.5mbps
outbound
on its interface e0/1.
solution:
class-map match-all ABOVE_1250_BYTES
match packet length min 1250
policy-map QoS
class ABOVE_1250_BYTES
police cir 2500000
here was used police cir. As far as I understood the difference between
Generic traffic shaping
and FRTS only one is that GTS could be applied not only on Frame-relay
interfaces but also on ethernet and others. Do I uderstand it
correctly??
Could in this example the GTS be used?? Here is the ethernet interface.
As
far as I understand the
policie cir command does the same thing ad GTS can. But GTS has more
options
to configure.
Do I understand correctly the difference between GTS, police cir command
(how it is called in another way??) and FRTS. Are there any other
differences.
Thank you for replies. This questions doesn't let me sleep.
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