• Tag : QoS


QoS Basics

Introduction Quality of service is the ability to provide different priority to different applications, users, or data flows, or to guarantee a certain level of performance to a data flow. QoS processes apply to traffic that flows through Ethernet ports and control planes. These processes can modify data fields (CoS or DSCP) or assign data streams to traffic classes for prioritized handling. QoS Features Consider the following topology for the following examples. I. Classification Quality of Service defines a method of differentiating data streams to provide varying levels of service to the different streams. Criteria determining a packet’s priority level...
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Match COS/Vlan + COS in QoS Policy-Map on Sand

Description Classification of packets based on COS/Vlan+COS bits in 802.1q header. Platform compatibility DCS-7020R DCS-7020RA DCS-7020SR-24C2 DCS-7020SRG-24C2-F DCS-7280R DCS-7280E DCS-7280R2 DCS-7280SRA DCS-7280SRM-40CX2 DCS-7280TR DCS-7280QR-C36 DCS-7280SRAM-48C6 DCS-7280TRA-48C6 DCS-7280TRA-48C6-M DCS-7500E DCS-7500R DCS-7500R2 DSC-7504 DCS-7508 DCS-7512 DCS-7516 On DCS-7504 and DCS-7508 modular chassis we support Match COS/Vlan + COS only on 7500E,7500R & 7500R2 linecards. TCAM Profile Configuration To support match on cos / vlan + cos bits, we need to apply a TCAM profile that supports matching on cos / vlan + cos bits. hardware tcam profile qos-cos feature acl port ip sequence 45 key size limit 160 key field dscp dst-ip...
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Per Port COS-to-TC

Per Port COS-to-TC Description This feature adds support to configure and apply different COS-to-TC profiles on Front Panel Ports and Port-Channel Interfaces, as opposed to having a global COS-to-TC mapping for all the interfaces. The TC is derived from this map, only if the interface is in COS Trust mode or Untrusted mode. Platform compatibility DCS-7280R DCS-7500R DCS-7504 DCS-7508 DCS-7512 DCS-7516 DCS-7280R2 DCS-7500R2 DCS-7500E DCS-7280E DCS-7500E DCS-7020R DCS-7280SRA DCS-7280TR DCS-7280QR-C36 DCS-7280SR-48C6 DCS-7280SRAM-48C6 DCS-7280SRM-40CX2 DCS-7280TRA-48C6 DCS-7280TRA-48C6-M For Modular Chassis, we support COS-to-TC profiles only on 7500E, 7500R, and 7500R2 Linecards.  Configuration In order to use this feature, a COS-to-TC profile is...
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Match on NHG in QOS class-map policy

Description Enhancement of QOS class-maps to match on nexthop-groups along with dscp ( dscp being optional ) to set any QOS actions including rate-limiting at ingress Platform compatibility DCS-7280R DCS-7500R DCS-7280R2 DCS-7500R2 DCS-7020R Configuration Creating a new user defined Tcam profile The user has to create a new TCAM profile, either from scratch or fork it out of any of the existing TCAM profiles in the system. For example, to fork the given pbr-match-nexthop-group  profile into a new profile qos-match-nexthop-group : switch(config)#hardware tcam switch(config-hw-tcam)#profile qos-match-nexthop-group copy pbr-match-nexthop-group                     Modify Ip Qos and Ipv6...
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QoS per IP

Hi, It is possible to shape or limit egress traffic bandwidth to a certain IP on a interface? I have a 7050S (Trident platform) Many thanks, Diego

Qos Policy Map Counter

This feature is an extension of Qos Policy. It allows the user to configure Qos Policy Map counters. If a class-map is configured for a policer action then the conformed and non-conformed packet and byte counters are displayed for that class-map. Otherwise the number of packets and bytes hitting the class-map are shown. Platform compatibility DCS-7280E DCS-7020R DCS-7280R DCS-7280R2 DCS-7500R2 Configuration Following command allocates the Counter Engines for Qos which actually count and store the counter value. switch(config)#[no|default] hardware counter feature qos in Arad Fixed system Currently, there is not enough space in TCAM action bank for Qos counter feature. So...
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qos map to limit egress traffic

Hello all, I have an Arista DCS-7148SX-F-SP, and would like to limit ingress traffic and egress traffic. So for ingress traffic it’s easy, i used “shape rate 10000” on my interface. But for egress, I tried to used qos map, I have the FM4000 platform. So I do this : SW1(config-if-Et1)#no qos trust SW1(config-if-Et1)#qos cos 3 SW1(config)#qos map cos 3 to traffic-class 3   SW1(config)#qos map traffic-class 3 to cos 3 SW1(config)#qos map traffic-class 3 to tx-queue 3 SW1(config-if-Et1)#tx-queue 3   SW1(config-if-Et1-txq-1)#shape rate 10000 But it’s doesn’t work, and when i do “sh run” i don’t see the following line :...
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Control WRED threshold for non-ECT packets

This feature is an extension to the Explicit Congestion Notification (ECN) functionality for non-ECN-Capable Transport (non-ECT). It allows the user to configure Weighted Random Early Detection (WRED) thresholds for dropping non-ECT packets, which enables non-ECT packets to participate in WRED congestion avoidance independent of the ECT packets. Platform compatibility DSC-7050X DCS-7250X DCS-7300X Configuration The non-ECT thresholds are configured at an interface’s tx-queue level. The drop profile is defined by minimum-threshold, maximum-threshold, and drop-probability. The units for thresholds can be given in segments, bytes, kilobytes or megabytes. Please note that global config level qos random-detect ecn allow non-ect configuration is needed to allow (and not...
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Best Practise setup for NAS, iSCSI storage

Hi   I have 3 x 2 unit  MLAG setup.  on 2 of my mlag’s I have some Equal Logic storage.   I was wondering if there was any best practise or white paper on whats the next setup for my arista switches (DCS-7050SX-64-F), DCB is the requirement from equallogic, but I believe I can setup some QOS ?   any pointers ref would be welcome Alex

QoS Policy on Outbound Packets

I cannot choose to put a service-policy with output of packets, only input. This is on both a physical and vlan interface. Is this a limitation with code or hardware? There is only “input” available on the command “service-policy type qos input <name>”. I am running version 4.15.5M on TridentII chips (DCS-7050SX-64-F). ThanksTim

Shared ACL based QoS on SVIs

ACL based QoS programmed on SVIs can share hardware resources starting from EOS-4.17.0F. This results in a more efficient utilization of the system resources and is particularly useful for environments with a few, potentially large, QoS policy-maps applied to multiple SVIs. For more information on ACL based QoS support on SVIs, refer to ACL based Qos on SVIs. Platform compatibility DCS-7010 DCS-7050X DCS-7250X DCS-7300X Configuration By default, the sharing of ACLs is disabled. The CLI command used to enable it is: 7050(config)#hardware access-list qos resource sharing vlan in The CLI command to disable it is: 7050(config)#no hardware access-list qos resource sharing vlan in Status Show Commands...
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Show command for fabric interfaces

The show command ‘show qos interface fabric’ was introduced for DCS-7250QX and DCS-7300X series starting EOS-4.15.2F release, which just displayed the Qos profile applied on the fabric interface. This command has now been modified to display detailed information about configured/operational values of interface Qos configurations, as is shown by the command – ‘show qos interfaces <intfName>’ for front panel ports. Variants of the command have also been added to display information of fabric ports across all chips and to display ECN thresholds for ECN configuration on the ports. Platform compatibility DCS-7250X DCS-7300X Configuration All configurations on the fabric port is through...
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QoS Profiles

QoS profiles are a collection of interface level QoS configuration commands, that are used as an alternate means of input to the traditional CLI. They help in reducing clutter in the running configuration. A possible use-case would be when there are common QoS configuration statements that need to be applied or modified on multiple interfaces. Introduced first for the DCS-7250QX and DCS-7300X series with the EOS-4.15.2F release, they have been improved upon in this release. Previously, they were applicable only on the fabric interface and supported priority flow control, tx-queue ECN, WRED and guaranteedBandwidth configurations. Now they are also applicable...
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