From: Brian McGahan (bmcgahan@internetworkexpert.com)
Date: Thu Mar 18 2004 - 18:36:44 GMT-3
Brennan,
This was rehashed just this week. The "bandwidth remaining percent"
command does not do what that document says it does. See the thread
"converting custom queue to cbwfq" from this week and last.
Regarding a drop, this will only occur when the entire output queue
of the interface is full, and the class in question has met or exceeded its
allocated reservation.
HTH,
Brian McGahan, CCIE #8593
bmcgahan@internetworkexpert.com
Internetwork Expert, Inc.
http://www.InternetworkExpert.com
Toll Free: 877-224-8987 x 705
Outside US: 775-826-4344 x 705
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> Brennan_Murphy@NAI.com
> Sent: Thursday, March 18, 2004 12:55 PM
> To: ccielab@groupstudy.com
> Subject: RE: CBWFQ over ATM: Questions on Show policy interface output
>
> The packets are dropped when the class is full and there is no
> unallocated bw available...ie, congestion.
> When all classes are full, they share the remaining bandwidth in
> proportion to the percentage
> of traffic protected by the bandwidth percent statement. So in this
> case, I have a class with 1% protected....when it competes with other
> classes, such as the Gold class of 25%, it gets 1 byte for every 25 gold
> bytes.
>
> This ratio can be overridden using "bandwidth remaining percent" . So
> for example, I can
> set it up so my platinum class gets 80% of remaining bw...other classes
> get whatever else I config.
>
> Does this sound right?
>
> Thanks,
> BM
>
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> Murphy, Brennan
> Sent: Thursday, March 18, 2004 10:50 AM
> To: ccielab@groupstudy.com
> Subject: CBWFQ over ATM: Questions on Show policy interface output
>
>
> I need help understanding the output from a show policy interface atm
> command below. This is coming from a 7500 series router running
> 12.2.16a. Trying to understand under what circumstances packet drops
> occur in the classes. Are packets dropped when the banwidth percent for
> a class is exceeded or when the total banwidth available on the ATM VC
> is exceeded. The output on this command seems to suggest that when the
> bw percent chosen for the class is exceeded, packets are dropped.
>
> pladcrt1#sh pol int atm10/0/0.12
> ATM10/0/0.12: VC 2/212 -
>
> Service-policy output: CBWFQQ
>
> queue stats for all priority classes:
> queue size 0, queue limit 57
> packets output 0, packet drops 0
> tail/random drops 0, no buffer drops 0, other drops 0
>
> Class-map: CONTROL (match-all)
> 13482 packets, 986994 bytes
> 5 minute offered rate 5000 bps, drop rate 0 bps
> Match: ip dscp cs6
> queue size 0, queue limit 1
> packets output 13482, packet drops 0
> tail/random drops 0, no buffer drops 0, other drops 0
> Bandwidth: 5.0%, kbps 38
>
> Class-map: VOICE (match-all)
> 0 packets, 0 bytes
> 5 minute offered rate 0 bps, drop rate 0 bps
> Match: ip dscp ef
> Priority: 30% (230 kbps), burst bytes 5750, b/w exceed drops: 0
>
> Class-map: VIDEO (match-all)
> 0 packets, 0 bytes
> 5 minute offered rate 0 bps, drop rate 0 bps
> Match: ip dscp cs4
> queue size 0, queue limit 1
> packets output 0, packet drops 0
> tail/random drops 0, no buffer drops 0, other drops 0
> Bandwidth: 1.0%, kbps 7
>
> Class-map: PLATINUM (match-all)
> 651 packets, 444300 bytes
> 5 minute offered rate 0 bps, drop rate 0 bps
> Match: ip dscp cs3
> queue size 0, queue limit 1
> packets output 600, packet drops 51
> tail/random drops 51, no buffer drops 0, other drops 0
> Bandwidth: 1.0%, kbps 7
>
> Class-map: GOLD (match-all)
> 0 packets, 0 bytes
> 5 minute offered rate 0 bps, drop rate 0 bps
> Match: ip dscp cs2
> queue size 0, queue limit 47
> packets output 0, packet drops 0
> tail/random drops 0, no buffer drops 0, other drops 0
> Bandwidth: 25.0%, kbps 192
>
> Class-map: SILVER (match-all)
> 1116 packets, 118934 bytes
> 5 minute offered rate 0 bps, drop rate 0 bps
> Match: ip dscp cs1
> queue size 0, queue limit 1
> packets output 1096, packet drops 20
> tail/random drops 20, no buffer drops 0, other drops 0
> Bandwidth: 5.0%, kbps 38
>
> Class-map: BRONZE (match-all)
> 466036 packets, 165312557 bytes
> 5 minute offered rate 170000 bps, drop rate 0 bps
> Match: ip dscp default
> queue size 0, queue limit 1
> packets output 459726, packet drops 6315
> tail/random drops 6315, no buffer drops 0, other drops 0
> Bandwidth: 1.0%, kbps 7
>
> Class-map: DEFAULT (match-all)
> 0 packets, 0 bytes
> 5 minute offered rate 0 bps
> Match: ip dscp default
>
> Class-map: class-default (match-any)
> 1729 packets, 792398 bytes
> 5 minute offered rate 0 bps, drop rate 0 bps
> Match: any
> queue size 0, queue limit 7
> packets output 1700, packet drops 29
> tail/random drops 29, no buffer drops 0, other drops 0
>
>
> Thanks,
> BM
>
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