Hi Everyone
I have an issue with an ASR 1001. The problem occurs with MQC shaping applied to a gigabit interface in the outbound direction. The CIR of the provider we are using is 100Mb/sec, so we are shaping to that value. However when reported traffic levels are about 60Mb/sec, we see a steady increase in output drops.
Here is the relevant config;
policy-map QOS-OUT
class PREMIUM
priority 6144
class ENHANCED-1
bandwidth 1024
class class-default
set dscp af11
policy-map OUT
class class-default
shape average 100000000
service-policy QOS-OUT
interface GigabitEthernet0/0/0
no ip address
no ip redirects
no ip proxy-arp
load-interval 30
no negotiation auto
interface GigabitEthernet0/0/0.101
bandwidth 100000
encapsulation dot1Q 101
ip address x.x.x.x x.x.x.x
no ip redirects
no ip proxy-arp
service-policy output OUT
The physical interface shows the following ( note we are using dot1q sub interfaces but only have one in use, so the stats on physical interface only relate to this one)
sh int g0/0/0
GigabitEthernet0/0/0 is up, line protocol is up
Hardware is ASR1001, address is 649e.f329.3d80 (bia 649e.f329.3d80)
Description:
MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec,
reliability 255/255, txload 17/255, rxload 6/255
Encapsulation 802.1Q Virtual LAN, Vlan ID 1., loopback not set
Keepalive not supported
Full Duplex, 1000Mbps, link type is force-up, media type is SX
output flow-control is on, input flow-control is on
ARP type: ARPA, ARP Timeout 04:00:00
Last input 02:20:54, output 02:20:54, output hang never
Last clearing of "show interface" counters 00:03:11
Input queue: 0/375/0/0 (size/max/drops/flushes); Total output drops: 267
Queueing strategy: Class-based queueing
Output queue: 0/40 (size/max)
30 second input rate 26851000 bits/sec, 12150 packets/sec
30 second output rate 60529000 bits/sec, 18885 packets/sec
2330446 packets input, 709862871 bytes, 0 no buffer
Received 10 broadcasts (0 IP multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 0 multicast, 0 pause input
3541955 packets output, 1634851452 bytes, 0 underruns
The policy-map shows;
snip
Class-map: class-default (match-any)
3217551 packets, 1484943980 bytes
30 second offered rate 60418000 bps, drop rate 4000 bps
Match: any
Queueing
queue limit 416 packets
(queue depth/total drops/no-buffer drops) 0/267/0
(pkts output/bytes output) 3535758/1630202127
shape (average) cir 100000000, bc 1000000, be 1000000
target shape rate 100000000
I have also tried increasing the hold queue, however this does not help with the drops. Increasing the shaping rate to 200Mb/sec gets rid of almost all the drops (not quite all!) but is not what we need.
I think that we should see some drops when rates spike above 100mb, however the amount we are seeing seems excessive?
Does anyone have any views on this?
Thanks
Mike
