[c-nsp] Packet drops on ME3600X policy-map
Lobo
lobotiger at gmail.com
Tue Oct 21 13:23:04 EDT 2014
Hey everyone, I'm trying to figure this one out and I'm banging my head
on it. I've got a relatively simple child-parent policy-map configured
on a port. The shaping is set to 400M but with traffic at less than
300M I'm seeing consistent drop rates specifically in the class-default
section of the child policy.
This is the configuration:
policy-map BACKBONE_OUT_QOS
class RT_QOS_GROUP
priority
set mpls experimental topmost 5
set cos 5
class CT_QOS_GROUP
bandwidth remaining percent 5
set mpls experimental topmost 6
set cos 6
class FC2_QOS_GROUP
bandwidth remaining percent 10
set mpls experimental topmost 4
set cos 4
class FC_QOS_GROUP
bandwidth remaining percent 50
set mpls experimental topmost 3
set cos 3
class BC_QOS_GROUP
bandwidth remaining percent 20
set mpls experimental topmost 2
set cos 2
class SC_QOS_GROUP
set mpls experimental topmost 1
set cos 1
class class-default
set mpls experimental topmost 0
set cos 0
!
policy-map BACKBONE_OUT_400M
class class-default
shape average 400000000
service-policy BACKBONE_OUT_QOS
!
The class-maps are matching their respective qos-group markings.
And it's applied to the physical interface:
interface GigabitEthernet0/23
switchport trunk allowed vlan blah
switchport mode trunk
mtu 9800
load-interval 30
service-policy input BACKBONE_IN
service-policy output BACKBONE_OUT_400M
end
The output of a show command is as follows:
#sh policy-map int g0/23 output
GigabitEthernet0/23
Service-policy output: BACKBONE_OUT_400M
Class-map: class-default (match-any)
13340674 packets, 12526672443 bytes
30 second offered rate 293739000 bps, drop rate 432000 bps
Match: any
Traffic Shaping
Average Rate Traffic Shaping
Shape 400000 (kbps)
Output Queue:
Default Queue-limit 49152 bytes
Tail Packets Drop: 16218
Tail Bytes Drop: 15933830
Service-policy : BACKBONE_OUT_QOS
Class-map: RT_QOS_GROUP (match-any)
0 packets, 0 bytes
30 second offered rate 0000 bps, drop rate 0000 bps
Match: qos-group 5
Strict Priority
set mpls exp topmost 5
set cos 5
Queue-limit current-queue-depth 0 bytes
Output Queue:
Default Queue-limit 49152 bytes
Tail Packets Drop: 0
Tail Bytes Drop: 0
Class-map: CT_QOS_GROUP (match-any)
358 packets, 98876 bytes
30 second offered rate 0000 bps, drop rate 0000 bps
Match: qos-group 6
Bandwidth Remaining 5 (percent)
set mpls exp topmost 6
set cos 6
Queue-limit current-queue-depth 0 bytes
Output Queue:
Default Queue-limit 49152 bytes
Tail Packets Drop: 0
Tail Bytes Drop: 0
Class-map: FC2_QOS_GROUP (match-any)
0 packets, 0 bytes
30 second offered rate 0000 bps, drop rate 0000 bps
Match: qos-group 4
Bandwidth Remaining 10 (percent)
set mpls exp topmost 4
set cos 4
Queue-limit current-queue-depth 0 bytes
Output Queue:
Default Queue-limit 49152 bytes
Tail Packets Drop: 0
Tail Bytes Drop: 0
Class-map: FC_QOS_GROUP (match-any)
0 packets, 0 bytes
30 second offered rate 0000 bps, drop rate 0000 bps
Match: qos-group 3
Bandwidth Remaining 50 (percent)
set mpls exp topmost 3
set cos 3
Queue-limit current-queue-depth 0 bytes
Output Queue:
Default Queue-limit 49152 bytes
Tail Packets Drop: 0
Tail Bytes Drop: 0
Class-map: BC_QOS_GROUP (match-any)
0 packets, 0 bytes
30 second offered rate 0000 bps, drop rate 0000 bps
Match: qos-group 2
Bandwidth Remaining 20 (percent)
set mpls exp topmost 2
set cos 2
Queue-limit current-queue-depth 0 bytes
Output Queue:
Default Queue-limit 49152 bytes
Tail Packets Drop: 0
Tail Bytes Drop: 0
Class-map: SC_QOS_GROUP (match-any)
0 packets, 0 bytes
30 second offered rate 0000 bps, drop rate 0000 bps
Match: qos-group 1
set mpls exp topmost 1
set cos 1
Queue-limit current-queue-depth 0 bytes
Output Queue:
Default Queue-limit 49152 bytes
Tail Packets Drop: 0
Tail Bytes Drop: 0
Class-map: class-default (match-any)
13340316 packets, 12526573567 bytes
30 second offered rate 293737000 bps, drop rate 432000 bps
Match: any
set mpls exp topmost 0
set cos 0
Queue-limit current-queue-depth 0 bytes
Output Queue:
Default Queue-limit 49152 bytes
Tail Packets Drop: 16218
Tail Bytes Drop: 15933830
The number of tail drops is pretty close to the output drops shown on
the interface itself too:
rocpe06#sh int g0/23
GigabitEthernet0/23 is up, line protocol is up (connected)
<snip>
MTU 9800 bytes, BW 1000000 Kbit/sec, DLY 10 usec,
reliability 255/255, txload 74/255, rxload 26/255
Encapsulation ARPA, loopback not set
Keepalive not set
Full-duplex, 1000Mb/s, media type is SX
input flow-control is off, output flow-control is unsupported
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:00, output 00:00:00, output hang never
Last clearing of "show interface" counters 00:05:40
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 15365
Queueing strategy: fifo
Output queue: 0/40 (size/max)
30 second input rate 105779000 bits/sec, 35781 packets/sec
30 second output rate 293211000 bits/sec, 38999 packets/sec
11830165 packets input, 4313484039 bytes, 0 no buffer
Received 15400 broadcasts (6262 multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 6262 multicast, 0 pause input
0 input packets with dribble condition detected
13145027 packets output, 12329007673 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
12 unknown protocol drops
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier, 0 pause output
0 output buffer failures, 0 output buffers swapped out
!
Any thoughts on whether it's the policy-map that needs tweaking somehow
or if it's some other issue? All of the traffic that is being dropped is
traffic that is general internet but some folks have started to notice
some packet loss.
Any input would be appreciated.
Jose
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