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TM
AlliedWare OS
How To | Configure QoS on AT-9900, x900-48, and x900-24
Series Switches
Introduction
This document describes some generic configuration examples for Quality of Service (QoS)
on AT-9900 and x900 series switches running the AlliedWare OS.
What information will you find in this document?
This document provides information on the following sections:
"1. Setting the egress rate" on page 2
"2. Setting the priority on a p
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1. Setting the egress rate 1. Setting the egress rate Example 1-1: Setting the egress limit of a switch port Port 24 Command: set switch port=24 egresslimit=640 This command will set the egress limit of port 24 to 640kbps. The granularity is 640kbps. Page 2 | AlliedWare™ OS How To Note: QoS configuration
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1. Setting the egress rate Example 1-2: setting the maximum bandwidth limit per ingress port Ingress rate limiting cannot be configured on the port per se, but is achieved by creating a QoS policy with a bandwidth limited traffic class, and applying that policy to each port. Port 24 Ingress ports 1-20 create class=1 create qos flow=1 add qos flow=1 class=1 create qos traff=1 add qos traff=1 flow=1 set qos traff=1 maxbandwidth=128kbps maxburst=5kbyte dropbw=yes create qos poli=1 add qos pol
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1. Setting the egress rate Example 1-3: Setting the maximum bandwidth limit for each user In example 1-1, we configured an egress rate on ports. But the granularity of that bandwidth limiting was multiples of 640kbps. To achieve a finer-grained limiting on egress, it is necessary to make use of traffic classes. In this example we assume that there is one device with a known IP address, attached to each port. A traffic class will be created for each such IP address, and a maximum bandwidth ap
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1. Setting the egress rate Example 1-4: Setting the maximum bandwidth limit for each IP subnet This example is very similar to example 1-3, except that it is assumed that a whole subnet is attached to each port, not just a single device on each port. Port 24 Internet connection Users connected to the switch downloading files from the Internet (192.168.1.0/24 - 192.168.23.0/24) create class=1 ipda=192.168.1.0/24 create class=2 ipda=192.168.2.0/24 create class=3 ipda=192.168.3.0/24 ... create q
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1. Setting the egress rate Example 1-5: Setting the maximum bandwidth limit of VLANs Port 24 Ingress ports 1-20 (these ports are carrying a mixture of VLAN2, VLAN3 and VLAN4 packets, either with or without VLAN tags) create class=1 vlan=2 create class=2 vlan=3 create class=3 vlan=4 create qos flow=1 add qos flow=1 class=1 create qos flow=2 add qos flow=2 class=2 create qos flow=3 add qos flow=3 class=3 create qos traff=1 add qos traff=1 flow=1 set qos traff=1 maxbandw=256kbps maxburst=5kb
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2. Setting the priority on a packet 2. Setting the priority on a packet Example 2-1: Setting the Layer 2 (VLAN/802.1p) priority per ingress port Here we assign different 802.1p values to packets arriving on different ports. These values are also known as the Layer 2 (L2) or VLAN priority. Port 24 Ingress ports 1-20 (these ports MAY be carrying a mixture of packets from different VLAN packets, either with or without VLAN tags) create class=1 create qos flow=1 add qos flow=1 class=1 create qo
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2. Setting the priority on a packet Example 2-2: Setting the Layer 2 (VLAN/802.1p) priority per VLAN Port 24 Ingress ports 1-20 (these ports MAY be carrying a mixture of VLAN2, VLAN3, and VLAN4 packets either with or without VLAN tags) create class=1 vlan=2 create class=2 vlan=3 create class=3 vlan=4 create qos flow=1 add qos flow=1 class=1 create qos flow=2 add qos flow=2 class=2 create qos flow=3 add qos flow=3 class=3 create qos traff=1 add qos traff=1 flow=1 set qos traff=1 mark=11 pr
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2. Setting the priority on a packet Example 2-3: Setting the Layer 3 (TOS/DCSP) priority per ingress port Use the same configuration provided in Example 2-1 on page 7, but change the following line: set qos dscpmap=premarking dscp= newpriority= to set qos dscpmap=premarking dscp= newdscp= Example 2-4: Setting the Layer 3 (TOS/DSCP) priority per VLAN Use the same configuration provided in Example 2-2 on page 8, but change the following line:
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3. Setting the egress queues 3. Setting the egress queues In this section we look at methods for directing certain packets into certain queues on the egress port. Example 3-1: Setting the egress queue according to the L2 priority of the incoming packet The priority-to-queue map is a straightforward method for assigning packets to egress on the basis of the packets’ 802.1p values. Port 24 Ingress ports 1-20 (these ports MAY be carrying a mixture of packets from different VLAN packets either
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3. Setting the egress queues Example 3-2: Setting the egress queue according to the ingress port Port 24 Ingress ports 1-20 (these ports MAY be carrying a mixture of packets from different VLAN packets either with or without VLAN tags) create class=1 create qos flow=1 add qos flow=1 class=1 create qos traff=1 add qos traff=1 flow=1 set qos traff=1 mark=11 premarking=usemark set qos dscpmap=premarking dscp=11 newqueue=6 create qos poli=1 add qos poli=1 traff=1 set qos port=1 poli=1 create q
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3. Setting the egress queues Example 3-3: Configuring WRR for egress queues This example is used for configuring WRR on egress queues according to the ingress port of the traffic. Port 24 Ingress ports 1-3 (these ports MAY be carrying a mixture of packets from different VLAN packets either with or without VLAN tags) create class=1 create qos flow=1 add qos flow=1 class=1 create qos traff=1 add qos traff=1 flow=1 set qos traff=1 mark=11 premarking=usemark set qos dscpmap=premarking dscp=11
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Full QoS scenario 1: tiered services for a single customer Full QoS scenario 1: tiered services for a single customer In this section, we will build up a relatively complex QoS configuration to support a scenario requiring quite precise control over the traffic passing through the switch. The scenario is an ISP providing connectivity for a customer, and offering different levels of service for different types of traffic. The customer is connected to port 1 of the switch, and the uplink to th
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Full QoS scenario 1: tiered services for a single customer Bronze traffic is also allowed to burst up to the full egress bandwidth of the uplink port, but when congestion occurs, will be throttled back in favour of Gold traffic, and will share the remaining bandwidth with Silver traffic in a Weighted Round Robin fashion. The ISP makes no guarantees at all with regard to delivery of Bronze traffic across their network; it will be delivered on a best-effort basis. Identify the types of traffic
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Full QoS scenario 1: tiered services for a single customer The act of assigning packets in a particular traffic class to a particular egress queue is achieved in the pre-marking process. This requires that the pre-marking DSCP map table be set up to send packets to appropriate queues, based on their DSCP value: set qos dscpmap=premark dscp=0 newqueue=1 set qos dscpmap=premark dscp=30 newqueue=2 set qos dscpmap=premark dscp=40 newqueue=6 The traffic classes all need to be configured to use the
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Full QoS scenario 1: tiered services for a single customer Step 3—Set the bandwidth limits The Gold traffic must be strictly limited to 2Mbps This is achieved by configuring a maxbandwidth on that traffic class, and dropping bandwidthclass 3 traffic: set qos trafficclass=3 maxbandwidth=2mbps maxburst=20Kbytes dropbwclass3=true For silver traffic, there is preferential treatment for the first 5Mbps of traffic. So, when there is congestion, you want to still be getting 5Mbps of Silver traffic
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Full QoS scenario 1: tiered services for a single customer RED curves—a refresher Random Early Discard curves are bandwidth class aware, and can drop lower priority packets when severe congestion occurs, with progressively more and higher priority packets dropped until congestion is eased. This is useful for TCP flows, because the sender will slow the rate of transmission when it detects a packet loss. These curves are very lenient on green traffic, but will quickly start dropping yellow and
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Full QoS scenario 2: bandwidth limiting of multiple customers Full QoS scenario 2: bandwidth limiting of multiple customers In this section, we will build up another relatively complex QoS configuration to support a different scenario. The scenario is an ISP providing connectivity for several independent customers (one per port). Different customers have signed up for different deals that provide different levels of service. In this example, to keep things simple, we will just consider the c
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Full QoS scenario 2: bandwidth limiting of multiple customers The configuration required to impose these bandwidth limits would be: Limiting the outgoing traffic: create qos policy=1 dtcdropbwclass3=yes dtcmaxbandwidth=1Mbps dtcmaxburst=10Kb create qos policy=2 dtcdropbwclass3=yes dtcmaxbandwidth=10Mbps dtcmaxburst=10Kb create qos policy=3 dtcdropbwclass3=yes dtcmaxbandwidth=15Mbps dtcmaxburst=10Kb create qos policy=4 dtcdropbwclass3=yes dtcmaxbandwidth=5Mbps dtcmaxburst=10Kb create qos poli
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Full QoS scenario 2: bandwidth limiting of multiple customers create qos traff=9 set qos traff=9 maxband=5Mbps maxburst=10Kb dropbwc=yes add qos traff=9 flow=9 create qos traff=10 set qos traff=10 maxband=2Mbps maxburst=10Kb dropbwc=yes add qos traff=10 flow=10 create qos poli=6 add qos poli=6 traff=6-10 set qos port=24 poli=6 Step 2—Giving better service to VOIP traffic The ISP can offer to the customer a guarantee that VoIP traffic (up to a certain, relatively low, bandwidth) will be given
