05-18-2013 01:43 PM - edited 03-04-2019 07:56 PM
Hi everyone!!!
Someone knows which is the difference between Dual Rate Policing (police cir pir) and Shaping with Shape Peak?
Do they fill the token bucket every Tc?
Thanks a lot!!!!
Juan
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05-19-2013 02:39 AM
Hello
Shaping comes into play on your routers when your physical wan lines exceeds the your traffic rate by the ISP or your neighboring site- eg: your access rate is 2mb but your CIR ( committed information rate) is 1MB.
You can shape an average/peak/percent/rate/percent/percent remaining) And all are different
However Shape average and Shape peak allow bursting of traffic
Note:
Shaping is always an egress function- (exiting router) - queuing so router can use queuing tools to give better performance of particular type of packet
(Committed burst =BC & Excessive bursts=BE with a defined Time Interval = TC
Shape value = bps
Bc/Be value =bytes per second
Shaping average & peak tc/bc/values
Bc=Tc*CIR/8
Tc=Bc/Shaped rate(CIR
Be=Bc
TC= 0.125 default
TC= 0.025 for lower 320kps
TC= 0.010 for sensitive applications
BC=Tc*CIR
.125*640000=8000
Shape average ( default BC no BE)
Shape average 10240000
Shape average 10240000(bits) bc of 16000(bytes)
( this would send 16K bytes every .125 of a secs = 128000 byes *8 =1024000
Shape peak works a bit differently as it allows both Bc& Be to be sent over the TC
Shape peak
Shape peak 5120000 (mean to actual shape at 10240000)
Shape peak 5120000 (bits) bc of 8000(bytes) Be 8000(bytes)
( 5120000 (1+8000/8000 = 10240000)
Policing default - entering first device in network from being overrun with too much traffic
===============================================================
Single rate, single bucket/two colour ( no violate acction or Be configured/no PIR)
BC = CIR/32
or
BC =CIR*0.25/8
Be=0
Single rate, Dual bucket/three colour (violate acction and/or Be configured/ no PIR)
BC = CIR/32
or
BC =CIR*0.25/8
Be=BC
Dual rate, Dual bucket/three colour (PIR is configured)
BC = CIR/32
or
BC =CIR*0.25/8
BE - PIR/32
or
BE =CIR*0.25/8
res
Paul
Please don't forget to rate any posts that have been helpful.
Thanks.
05-18-2013 02:04 PM
Hello Juan,
The Dual Rate Policing allows you to achieve two sustained rates - the CIR and EIR, in each timing interval. In effect, the Dual Rate Policing allows you to continuously send data at the total rate of CIR+EIR. This is accomplished by refilling both the Bc and Be buckets every Tc interval independently and simultaneously.
Regarding the shape peak - this is a matter of quite extensive debates. I suggest reading the following threads:
https://supportforums.cisco.com/message/3297548#3297548
https://supportforums.cisco.com/message/3510675#3510675
Best regards,
Peter
05-18-2013 03:16 PM
Thanks Peter!!!
Do you know why do the people recomend utilize this formula to shaping?
Bc= policerate x 1,5 /8
05-19-2013 02:39 AM
Hello
Shaping comes into play on your routers when your physical wan lines exceeds the your traffic rate by the ISP or your neighboring site- eg: your access rate is 2mb but your CIR ( committed information rate) is 1MB.
You can shape an average/peak/percent/rate/percent/percent remaining) And all are different
However Shape average and Shape peak allow bursting of traffic
Note:
Shaping is always an egress function- (exiting router) - queuing so router can use queuing tools to give better performance of particular type of packet
(Committed burst =BC & Excessive bursts=BE with a defined Time Interval = TC
Shape value = bps
Bc/Be value =bytes per second
Shaping average & peak tc/bc/values
Bc=Tc*CIR/8
Tc=Bc/Shaped rate(CIR
Be=Bc
TC= 0.125 default
TC= 0.025 for lower 320kps
TC= 0.010 for sensitive applications
BC=Tc*CIR
.125*640000=8000
Shape average ( default BC no BE)
Shape average 10240000
Shape average 10240000(bits) bc of 16000(bytes)
( this would send 16K bytes every .125 of a secs = 128000 byes *8 =1024000
Shape peak works a bit differently as it allows both Bc& Be to be sent over the TC
Shape peak
Shape peak 5120000 (mean to actual shape at 10240000)
Shape peak 5120000 (bits) bc of 8000(bytes) Be 8000(bytes)
( 5120000 (1+8000/8000 = 10240000)
Policing default - entering first device in network from being overrun with too much traffic
===============================================================
Single rate, single bucket/two colour ( no violate acction or Be configured/no PIR)
BC = CIR/32
or
BC =CIR*0.25/8
Be=0
Single rate, Dual bucket/three colour (violate acction and/or Be configured/ no PIR)
BC = CIR/32
or
BC =CIR*0.25/8
Be=BC
Dual rate, Dual bucket/three colour (PIR is configured)
BC = CIR/32
or
BC =CIR*0.25/8
BE - PIR/32
or
BE =CIR*0.25/8
res
Paul
Please don't forget to rate any posts that have been helpful.
Thanks.
05-19-2013 02:22 PM
Guauuu pdriver and all guys, many thanks!!! i´m very grateful. Many thanks from Argentina.
I have some ask for pdriver.
1. Why you say that the Bc and Be are configured in bytes? Like Cisco and his command reference, there are values in bits.
2. Like some docs by Cisco, the shape average has Be by default, and the value is the same that Bc. Is this correct?
3.What does command allows me to have more bandwidth? shape average 512000 or shape peak 256000?
I think, that after a period of inactivity, the shape average allow me 512000, plus the Be.
Thanks a lot!!!!
Juan from Argentina.
05-19-2013 02:49 AM
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Posting
It's a rule-of-thumb to allow for bursting.
05-19-2013 05:29 AM
Hello Juan,
To be honest, I am not familiar with that formula. In any case, in these matters, I completely trust Joseph Doherty who answered that is a rule of thumb.
Best regards,
Peter
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