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RE: CBWFQ Question posted 05/03/2004
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Gad & Bob,
 
According to the Cisco documentation referenced below, the default queueing mechanism for the default class (class-default) is Flow-based WFQ.  When the "bandwidth" command is configured, it should disqualify that class as flow-based WFQ.
 
<snip>
Configuring the Class-Default Class Policy
The class-default class is used to classify traffic that does not fall into one of the defined classes. Once a packet is classified, all of the standard mechanisms that can be used to differentiate service among the classes apply. The class-default class was predefined when you created the policy map, but you must configure it. If no default class is configured, then by default the traffic that does not match any of the configured classes is flow classified and given best-effort treatment.
By default, the class-default class is defined as flow-based WFQ. However, configuring the default class with the bandwidth policy-map class configuration command disqualifies the default class as flow-based WFQ.
To configure a policy map and configure the class-default class to use tail drop, use the first global configuration command to specify the policy map name, then use the following policy-map class configuration commands to configure policy for the default class:
</snip>
 
http://www.cisco.com/en/US/products/sw/iosswrel/ps1830/products_feature_guide09186a0080087a84.html#25297
 
However, this isn't consistent with Gad's findings.
 
Gad - what IOS version are you running?
 
Ken

	-----Original Message----- 
	From: nobody@xxxxxxxxxxxxxx on behalf of Bob Sinclair 
	Sent: Sun 5/2/2004 8:40 PM 
	To: GAD; ccielab@xxxxxxxxxxxxxx 
	Cc: 
	Subject: Re: CBWFQ Question
	
	

	Gad,
	
	Class-default can use FIFO or WFQ.  I believe FIFO is the default.
	
	HTH,
	
	Bob Sinclair
	CCIE #10427, CISSP, MCSE
	www.netmasterclass.net
	
	----- Original Message -----
	From: "GAD" <gad@xxxxxxx>
	To: <ccielab@xxxxxxxxxxxxxx>
	Sent: Sunday, May 02, 2004 8:13 PM
	Subject: CBWFQ Question
	
	
	> Question. If you do not specify the "class-default" class in a policy-map,
	> the class-default class appears, but it does not say "Weighted fair
	> queueing". Can someone tell me what it IS doing?
	>
	> ex:
	>
	> class-map match-all Prec-5
	>   match ip precedence 5
	>
	> policy-map GAD
	>   class Prec-5
	>    bandwidth percent 90
	>
	> int s0
	>  service-policy outbound GAD
	>
	> R3#sho policy-map interface s0
	>
	>  Serial0
	>
	>   Service-policy output: GAD
	>
	>     Class-map: Telnet (match-all)
	>       0 packets, 0 bytes
	>       5 minute offered rate 0 bps, drop rate 0 bps
	>       Match: ip precedence 5
	>       Weighted Fair Queueing
	>         Output Queue: Conversation 265
	>         Bandwidth 90 (%) Max Threshold 64 (packets)
	>         (pkts matched/bytes matched) 0/0
	>         (depth/total drops/no-buffer drops) 0/0/0
	>
	>     Class-map: class-default (match-any)
	>       1 packets, 13 bytes
	>       5 minute offered rate 0 bps, drop rate 0 bps
	>       Match: any
	>
	> Difference when you add:
	>
	>   class class-default
	>    bandwidth percent 10
	>
	> To the policy map is:
	>
	> R3#sho policy-map interface s0
	>
	>  Serial0
	>
	>   Service-policy output: GAD
	>
	>     Class-map: Telnet (match-all)
	>       0 packets, 0 bytes
	>       5 minute offered rate 0 bps, drop rate 0 bps
	>       Match: ip precedence 5
	>       Weighted Fair Queueing
	>         Output Queue: Conversation 265
	>         Bandwidth 90 (%) Max Threshold 64 (packets)
	>         (pkts matched/bytes matched) 0/0
	>         (depth/total drops/no-buffer drops) 0/0/0
	>
	>     Class-map: class-default (match-any)
	>       38 packets, 494 bytes
	>       5 minute offered rate 0 bps, drop rate 0 bps
	>       Match: any
	>       Weighted Fair Queueing
	>         Output Queue: Conversation 266
	>         Bandwidth 10 (%) Max Threshold 64 (packets)
	>         (pkts matched/bytes matched) 0/0
	>         (depth/total drops/no-buffer drops) 0/0/0
	>
	> Notice the addition of the last 5 lines.
	>
	> So my question is, in the first example, what is the queuing mechaninsm if
	> not WFQ? Queueing for the interface is Weighted Fair as shown in in a show
	> int:
	>
	> Serial0 is up, line protocol is up
	>   Hardware is HD64570
	>   Internet address is 208.28.1.2/29
	>   MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,
	>      reliability 255/255, txload 1/255, rxload 1/255
	>   Encapsulation FRAME-RELAY, loopback not set
	>   Keepalive set (10 sec)
	>   LMI enq sent  43526, LMI stat recvd 43527, LMI upd recvd 0, DTE LMI up
	>   LMI enq recvd 0, LMI stat sent  0, LMI upd sent  0
	>   LMI DLCI 1023  LMI type is CISCO  frame relay DTE
	>   FR SVC disabled, LAPF state down
	>   Broadcast queue 0/64, broadcasts sent/dropped 2/0, interface broadcasts
	> 0
	>   Last input 00:00:04, output 00:00:04, output hang never
	>   Last clearing of "show interface" counters 5d01h
	>   Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
	>   Queueing strategy: weighted fair
	>   Output queue: 0/1000/64/0 (size/max total/threshold/drops)
	>      Conversations  0/1/256 (active/max active/max total)
	>      Reserved Conversations 2/2 (allocated/max allocated)
	>      Available Bandwidth 1158 kilobits/sec
	>   5 minute input rate 0 bits/sec, 0 packets/sec
	>   5 minute output rate 0 bits/sec, 0 packets/sec
	>      50821 packets input, 2826502 bytes, 0 no buffer
	>      Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
	>      0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
	>      43576 packets output, 570160 bytes, 0 underruns
	>      0 output errors, 0 collisions, 3 interface resets
	>      0 output buffer failures, 0 output buffers swapped out
	>      1 carrier transitions
	>      DCD=up  DSR=up  DTR=up  RTS=up  CTS=up
	>
	> I'm sure the answer is obvious somehwere, but I'm fried and it's eluding
	> me.
	>
	> Thanks!
	>
	> GAD
	>
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