TEST OF CAR WITH SPECIFIC NORMAL AND EXCEED BURST CONFIGURATION

TEST A

"unconfigure CBWFQ on output and do not send any UDP traffic. Just measure the TCP goodput when TCP is alone and just the policer is running. I expect that the goodput will be well below 1.3Mbps due to the known mismatch between a strict token bucket and a bursty TCP flow I expect that the higher the number of flows (thus the more realistic the test), the better the goodput" (C.Filsfils)

1 TCP stream:

netperf -H 192.65.183.20 -p 50060 -l 300 -- -S 250000,250000 -s 250000,250000

results:

	normal burst	exceed burst	num stream	rate lim Mbps	aggregate throughput	exceed pack num
CASE 1	50 msec ~ 64800 by	129600	1	1.296	1.23	797
/	"	"	5	"	1.25	NA
CASE 2	250 msec ~ 324000 by	648000	1	1.296	1.25	364
/	"	"	5	"	1.29	NA
CASE 3	500 msec ~ 648000 by	1296000	1	1.296	1.26	337
	"	"	5	"	1.33	NA
CASE 4	1 sec ~ 1296000	2592000	1	1.296	1.28	338
/	"	"	5	"	1.33	NA

Router configuration:

access list:

Extended IP access list 164
    permit tcp 192.168.73.0 0.0.0.255 192.65.183.0 0.0.0.255 (411012 matches)
    deny ip any any (1791040 matches)

CASE 1:

rate-limit input access-group 164 1296000 64800 129600 conform-action set-prec-transmit 5 exceed-action drop

router output (*):

    matches: access-group 164
      params:  1296000 bps, 64800 limit, 129600 extended limit
      conformed 32175 packets, 48491378 bytes; action: set-prec-transmit 5
      exceeded 797 packets, 1205538 bytes; action: drop
      last packet: 7796ms ago, current burst: 20356 bytes
      last cleared 00:05:11 ago, conformed 1279000 bps, exceeded 30000 bps

CASE 2:

rate-limit input access-group 164 1296000 324000 648000 conform-action set-prec-transmit 5 exceed-action drop

router output:

    matches: access-group 164
      params:  1296000 bps, 324000 limit, 648000 extended limit
      conformed 32440 packets, 48889228 bytes; action: set-prec-transmit 5
      exceeded 364 packets, 549976 bytes; action: drop
      last packet: 150484ms ago, current burst: 290100 bytes
      last cleared 00:07:34 ago, conformed 1282000 bps, exceeded 9000 bps

CASE 3:

rate-limit input access-group 164 1296000 648000 1296000 conform-action set-prec-transmit 5 exceed-action drop

router output:

    matches: access-group 164
      params:  1296000 bps, 648000 limit, 1296000 extended limit
      conformed 32798 packets, 49427880 bytes; action: set-prec-transmit 5
      exceeded 356 packets, 538984 bytes; action: drop
      last packet: 48956ms ago, current burst: 619448 bytes
      last cleared 00:05:58 ago, conformed 1277000 bps, exceeded 12000 bps

CASE 4:

rate-limit input access-group 164 1296000 1296000 2592000 conform-action set-prec-transmit 5 exceed-action drop

router output:

    matches: access-group 164
      params:  1296000 bps, 1296000 limit, 2592000 extended limit
      conformed 33160 packets, 49974828 bytes; action: set-prec-transmit 5
      exceeded 338 packets, 510612 bytes; action: drop
      last packet: 252ms ago, current burst: 1284744 bytes
      last cleared 00:05:06 ago, conformed 1302000 bps, exceeded 13000 bps

NOTE: "router output" is such that before the start of each test the command "clear counter" has been issued to reset the packet counters.

TEST B
"reconfigure CBWFQ and resend UDP traffic but with: NB = 1296000 * x ; EB = 1296000 * 2 * x
where x = 50ms (your test), 250ms, 500ms, 1s, where NB = normal burst, EB = excess burst
I expect that the goodput will improve and approach 1.3M when x will increase to 1s" (C.Filsfils)

1 UDP streams at 2 Mbps:

mgen -b 192.65.183.20 -i ge0 -s 1000 -r 200 -p 60000

1 TCP stream:

netperf -H 192.65.183.20 -p 50050 -l 300 -- -s250000,250000 -S250000,250000

results:

	normal burst	exceed burst	throughput Mbps
CASE 1	50 msec ~ 64800 byte	129600 byte	0.11
CASE 2	250 msec ~ 324000 byte	648000 byte	0.11
CASE 3	500 msec ~ 648000 byte	1296000 byte	0.11
CASE 4	1 sec ~ 1296000 byte	2592000 byte	0.11

Router output:

CASE 1:

    matches: access-group 164
      params:  1296000 bps, 64800 limit, 129600 extended limit
      conformed 3326 packets, 5001032 bytes; action: set-prec-transmit 5
      exceeded 31 packets, 46934 bytes; action: drop
      last packet: 3192ms ago, current burst: 0 bytes
      last cleared 00:05:22 ago, conformed 124000 bps, exceeded 1000 bps
qos#sh pol in atm1/0.8
 ATM1/0.8: VC 8/8 - output : wfq
  Weighted Fair Queueing
    Class wfq-tcp 
      Output Queue: Conversation 72
        Bandwidth 1300 (kbps) Packets Matched 2457
        mean queue depth: 0
        drops: class  random   tail     min-th   max-th   mark-prob 
               0      0        0        20       40       1/10
               1      0        0        22       40       1/10
               2      0        0        24       40       1/10
               3      0        0        26       40       1/10
               4      0        0        28       40       1/10
               5      0        0        30       40       1/10
               6      0        0        32       40       1/10
               7      0        0        34       40       1/10
               rsvp   0        0        36       40       1/10
    Class class-default 
      Output Queue: Conversation 73
        Bandwidth 200 (kbps) Packets Matched 42874 Max Threshold 64 (packets)
        (discards/tail drops) 498/0

CASE 2:

    matches: access-group 164
      params:  1296000 bps, 324000 limit, 648000 extended limit
      conformed 3348 packets, 5034340 bytes; action: set-prec-transmit 5
      exceeded 0 packets, 0 bytes; action: drop
      last packet: 2440ms ago, current burst: 0 bytes
      last cleared 00:05:18 ago, conformed 126000 bps, exceeded 0 bps
qos#sh pol in atm1/0.8
 ATM1/0.8: VC 8/8 - output : wfq
  Weighted Fair Queueing
    Class wfq-tcp 
      Output Queue: Conversation 72
        Bandwidth 1300 (kbps) Packets Matched 2537
        mean queue depth: 0
        drops: class  random   tail     min-th   max-th   mark-prob 
               0      0        0        20       40       1/10
               1      0        0        22       40       1/10
               2      0        0        24       40       1/10
               3      0        0        26       40       1/10
               4      0        0        28       40       1/10
               5      0        0        30       40       1/10
               6      0        0        32       40       1/10
               7      0        0        34       40       1/10
               rsvp   0        0        36       40       1/10
    Class class-default 
      Output Queue: Conversation 73
        Bandwidth 200 (kbps) Packets Matched 42635 Max Threshold 64 (packets)
        (discards/tail drops) 606/0

CASE 3:

    matches: access-group 164
      params:  1296000 bps, 648000 limit, 1296000 extended limit
      conformed 3335 packets, 5014658 bytes; action: set-prec-transmit 5
      exceeded 0 packets, 0 bytes; action: drop
      last packet: 1420ms ago, current burst: 0 bytes
      last cleared 00:05:17 ago, conformed 126000 bps, exceeded 0 bps
qos#sh pol in atm1/0.8 
 ATM1/0.8: VC 8/8 - output : wfq
  Weighted Fair Queueing
    Class wfq-tcp 
      Output Queue: Conversation 72
        Bandwidth 1300 (kbps) Packets Matched 2584
        mean queue depth: 0
        drops: class  random   tail     min-th   max-th   mark-prob 
               0      0        0        20       40       1/10
               1      0        0        22       40       1/10
               2      0        0        24       40       1/10
               3      0        0        26       40       1/10
               4      0        0        28       40       1/10
               5      0        0        30       40       1/10
               6      0        0        32       40       1/10
               7      0        0        34       40       1/10
               rsvp   0        0        36       40       1/10
    Class class-default 
      Output Queue: Conversation 73
        Bandwidth 200 (kbps) Packets Matched 42397 Max Threshold 64 (packets)
        (discards/tail drops) 676/0

CASE 4:

    matches: access-group 164
      params:  1296000 bps, 1296000 limit, 2592000 extended limit
      conformed 3324 packets, 4996550 bytes; action: set-prec-transmit 5
      exceeded 0 packets, 0 bytes; action: drop
      last packet: 60396ms ago, current burst: 0 bytes
      last cleared 00:12:53 ago, conformed 51000 bps, exceeded 0 bps
qos#sh pol in atm1/0.8 
 ATM1/0.8: VC 8/8 - output : wfq
  Weighted Fair Queueing
    Class wfq-tcp 
      Output Queue: Conversation 72
        Bandwidth 1300 (kbps) Packets Matched 2598
        mean queue depth: 0
        drops: class  random   tail     min-th   max-th   mark-prob 
               0      0        0        20       40       1/10
               1      0        0        22       40       1/10
               2      0        0        24       40       1/10
               3      0        0        26       40       1/10
               4      0        0        28       40       1/10
               5      0        0        30       40       1/10
               6      0        0        32       40       1/10
               7      0        0        34       40       1/10
               rsvp   0        0        36       40       1/10
    Class class-default 
      Output Queue: Conversation 73
        Bandwidth 200 (kbps) Packets Matched 43127 Max Threshold 64 (packets)
        (discards/tail drops) 652/0

Router configuration:

access list:

qos#sh access-li 165
Extended IP access list 165
    permit tcp host 192.168.73.2 192.65.183.0 0.0.0.255 (378832 matches)
    deny ip any any (1627475 matches)
qos#sh access-li 177
Extended IP access list 177
    permit tcp any any precedence critical (1054039 matches)
    deny ip any any (1129405 matches)

CBWFQ:

class-map wfq-tcp
  match access-group 177
policy-map wfq
  class wfq-tcp
   bandwidth 1300
   random-detect
  class class-default
   bandwidth 200
!
interface ATM1/0.8 point-to-point
 description to CERN (diffserv)
 bandwidth 2000
 ip address 192.168.60.6 255.255.255.252
 no ip directed-broadcast
 pvc 8/8 
  service-policy output wfq
  vbr-nrt 2000 2000 1
  encapsulation aal5mux ip
 !
!

for each case (from 1 to 4) CAR is configured as in test A (see above).

ADDITIONAL TEST FOR DEBUGGING
"

the tests advised above will quantify the impact of the policer on TCP goodput
if a looser policer does not increase the goodput, further tests will be required to narrow the cause of the problem:
on ingress, configure the following:
rate-limit input access-group 165 1296000 64000 128000 conform-action set-prec-transmit 5 exceed-action set-prec-transmit 5
keep the same output policy on the ATM vc
send both TCP and UDP traffic
run the test and measure the goodput. Here you will ONLY measure the impact of CBWFQ on the bandwdith allocation. This will confirm if there is an issue at this level. I expect roughly 80% of utilisation of the 1.3Mbps class (this number approaching 100% when the number of flows increase _and_ RED is configured within the TCP queue)." (C.Filsfils)

Result:
Application Throughput: 0.11 Mbps

Router output:

    matches: access-group 164
      params:  1296000 bps, 64000 limit, 128000 extended limit
      conformed 3276 packets, 4926452 bytes; action: set-prec-transmit 5
      exceeded 70 packets, 104860 bytes; action: set-prec-transmit 5
      last packet: 2004ms ago, current burst: 0 bytes
      last cleared 00:05:24 ago, conformed 121000 bps, exceeded 2000 bps
qos#sh pol in atm1/0.8
 ATM1/0.8: VC 8/8 - output : wfq
  Weighted Fair Queueing
    Class wfq-tcp 
      Output Queue: Conversation 72
        Bandwidth 1300 (kbps) Packets Matched 2543
        mean queue depth: 0
        drops: class  random   tail     min-th   max-th   mark-prob 
               0      0        0        20       40       1/10
               1      0        0        22       40       1/10
               2      0        0        24       40       1/10
               3      0        0        26       40       1/10
               4      0        0        28       40       1/10
               5      0        0        30       40       1/10
               6      0        0        32       40       1/10
               7      0        0        34       40       1/10
               rsvp   0        0        36       40       1/10
    Class class-default 
      Output Queue: Conversation 73
        Bandwidth 200 (kbps) Packets Matched 42680 Max Threshold 64 (packets)
        (discards/tail drops) 602/0

Router Configuration:

interface FastEthernet0/0
 description test LAN
[..]
 rate-limit input access-group 164 1296000 64000 128000 conform-action set-prec-transmit 5 exceed-action set-prec-transmit 5
[..]
class-map wfq-tcp
  match access-group 177
policy-map wfq
  class wfq-tcp
   bandwidth 1300
   random-detect
  class class-default
   bandwidth 200
!
interface ATM1/0.8 point-to-point
 description to CERN (diffserv)
 bandwidth 2000
 ip address 192.168.60.6 255.255.255.252
 no ip directed-broadcast
 pvc 8/8 
  service-policy output wfq
  vbr-nrt 2000 2000 1
  encapsulation aal5mux ip
 !
!

[end]