12-22-2009 08:23 AM - edited 03-04-2019 07:02 AM
Is it possible to create QoS policies based on a defined bandwidth? I have the following policy-map applied to an interface that is 100M. This 100M interface connects to an ISP managed router that is not smart enough to do the QoS policies we need. The other interface of the ISP router is 3.08M NxT1. My solution is to let my 2811 router perform the QoS but I need a way for the interface to prioritize bandwidht based on 3.0Mbps not 100Mbps.
policy-map att-cos-107
class voice
priority percent 60
class control
bandwidth percent 16
class critical
bandwidth percent 12
class class-default
fair-queue
random-detect dscp-based
Is it as simple as adding the bandwidth statement to the interface?
interface FastEthernet0/0
ip address 10.255.31.4 255.255.255.0
bandwidth 3080
duplex full
speed 100
12-22-2009 12:04 PM
Hi,
Yes it should work ;-) But be aware that 3.08M of T1 (PPP or HDLC based) is not 3.08 ethernet due to the overhead difference. The idea is to have always your FastEthernet interface to be congestioned (where you have your QoS policy) before your WAN link.
Ethernet header is longer so you should be able to configure a higher value than 3.08M to be closer to your actual WAN bandwidth but if you try to be too close you could have QoS flapping issue or not having QoS at all as you never reach your congestion point.
Another way to do it would be to use Hierarchichal QoS with a parent shaper.
HTH
Laurent.
12-23-2009 12:42 PM
Great idea with to use hierarchical QoS with a parent shaper. I altered my policy as below. Unfortunately I am still seeing some latency with voice traffic in the voice queue when the line is congested. Any ideas?
policy-map rg-cos-queue
class voice
priority percent 20
class control
bandwidth percent 32
class critical
bandwidth percent 24
class class-default
fair-queue
random-detect dscp-based
policy-map rg-cos
class class-default
shape average 3000000
fair-queue
random-detect dscp-based
service-policy rg-cos-queue
#show policy-map interface fa0/0
FastEthernet0/0
Service-policy output: rg-cos
Class-map: class-default (match-any)
6660429 packets, 1839471409 bytes
5 minute offered rate 211000 bps, drop rate 0 bps
Match: any
Traffic Shaping
Target/Average Byte Sustain Excess Interval Increment
Rate Limit bits/int bits/int (ms) (bytes)
3000000/3000000 18750 75000 75000 25 9375
Adapt Queue Packets Bytes Packets Bytes Shaping
Active Depth Delayed Delayed Active
- 0 6660082 1838976112 133073 163962630 no
Queueing
Flow Based Fair Queueing
Maximum Number of Hashed Queues 256
(total queued/total drops/no-buffer drops) 0/0/0
exponential weight: 9
dscp Transmitted Random drop Tail drop Minimum Maximum Mark
pkts/bytes pkts/bytes pkts/bytes thresh thresh prob
af11 0/0 0/0 0/0 32 40 1/10
af12 0/0 0/0 0/0 28 40 1/10
af13 0/0 0/0 0/0 24 40 1/10
af21 0/0 0/0 0/0 32 40 1/10
af22 0/0 0/0 0/0 28 40 1/10
af23 0/0 0/0 0/0 24 40 1/10
af31 0/0 0/0 0/0 32 40 1/10
af32 0/0 0/0 0/0 28 40 1/10
af33 0/0 0/0 0/0 24 40 1/10
af41 0/0 0/0 0/0 32 40 1/10
af42 0/0 0/0 0/0 28 40 1/10
af43 0/0 0/0 0/0 24 40 1/10
cs1 0/0 0/0 0/0 22 40 1/10
cs2 0/0 0/0 0/0 24 40 1/10
cs3 0/0 0/0 0/0 26 40 1/10
cs4 0/0 0/0 0/0 28 40 1/10
cs5 0/0 0/0 0/0 30 40 1/10
cs6 150273/10083987 0/0 0/0 32 40 1/10
cs7 0/0 0/0 0/0 34 40 1/10
ef 3731525/777951043 0/0 0/0 36 40 1/10
rsvp 0/0 0/0 0/0 36 40 1/10
default 2778631/1051436379 0/0 0/0 20 40 1/10
Service-policy : rg-cos-queue
Class-map: voice (match-any)
3731525 packets, 777951043 bytes
5 minute offered rate 175000 bps, drop rate 0 bps
Match: ip dscp ef (46)
3731524 packets, 777951043 bytes
5 minute rate 175000 bps
Queueing
Strict Priority
Output Queue: Conversation 136
Bandwidth 20 (%)
Bandwidth 600 (kbps) Burst 15000 (Bytes)
(pkts matched/bytes matched) 7004/1409103
(total drops/bytes drops) 0/0
Class-map: control (match-any)
0 packets, 0 bytes
5 minute offered rate 0 bps, drop rate 0 bps
Match: ip dscp af41 (34)
0 packets, 0 bytes
5 minute rate 0 bps
Queueing
Output Queue: Conversation 137
Bandwidth 32 (%)
Bandwidth 960 (kbps)Max Threshold 64 (packets)
(pkts matched/bytes matched) 0/0
(depth/total drops/no-buffer drops) 0/0/0
Class-map: critical (match-any)
0 packets, 0 bytes
5 minute offered rate 0 bps, drop rate 0 bps
Match: ip dscp af31 (26)
0 packets, 0 bytes
5 minute rate 0 bps
Match: access-group 103
0 packets, 0 bytes
5 minute rate 0 bps
Queueing
Output Queue: Conversation 138
Bandwidth 24 (%)
Bandwidth 720 (kbps)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)
2928904 packets, 1061520366 bytes
5 minute offered rate 35000 bps, drop rate 0 bps
Match: any
Queueing
Flow Based Fair Queueing
Maximum Number of Hashed Queues 128
(total queued/total drops/no-buffer drops) 0/347/0
exponential weight: 9
dscp Transmitted Random drop Tail drop Minimum Maximum Mark
pkts/bytes pkts/bytes pkts/bytes thresh thresh prob
af11 0/0 0/0 0/0 32 40 1/10
af12 0/0 0/0 0/0 28 40 1/10
af13 0/0 0/0 0/0 24 40 1/10
af21 0/0 0/0 0/0 32 40 1/10
af22 0/0 0/0 0/0 28 40 1/10
af23 0/0 0/0 0/0 24 40 1/10
af31 0/0 0/0 0/0 32 40 1/10
af32 0/0 0/0 0/0 28 40 1/10
af33 0/0 0/0 0/0 24 40 1/10
af41 0/0 0/0 0/0 32 40 1/10
af42 0/0 0/0 0/0 28 40 1/10
af43 0/0 0/0 0/0 24 40 1/10
cs1 0/0 0/0 0/0 22 40 1/10
cs2 0/0 0/0 0/0 24 40 1/10
cs3 0/0 0/0 0/0 26 40 1/10
cs4 0/0 0/0 0/0 28 40 1/10
cs5 0/0 0/0 0/0 30 40 1/10
cs6 150273/10083987 0/0 0/0 32 40 1/10
cs7 0/0 0/0 0/0 34 40 1/10
ef 0/0 0/0 0/0 36 40 1/10
rsvp 0/0 0/0 0/0 36 40 1/10
default 2778284/1050941082 307/437997 40/57300 20 40 1/10
12-23-2009 07:38 PM
Hi Daniel,
The default Tc is set to 25ms. You could try to reduce it to 10ms by configuring a Bc of 30000 in your shaper.
Also you can remove the fair-queue and the WRED from the parent class-default.
HTH
Laurent.
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