classofservice _junos

8/10/2019 ClassOfService _junos

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CLASS OF SERVICE


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2Copyright 2009 Juniper Networks, Inc. www.juniper.net

WHAT IS CLASS OF SERVICE?

CoS is designed to:Provide mechanisms for categorizing traffic Allow the router to use those categorizations to meet performancerequirements

CoS is not designed to:Make a network fasterReduce congestion


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TYPICAL USES OF COS

PrioritizationVoIPLatency-sensitive trafficPriority users

Congestion managementCongestion avoidance using REDCongestion control to ensure SLA maintenance

Bandwidth controlEnsure that different classes of traffic receive allocated bandwidth


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COS TERMINOLOGY

Forwarding classesIdentifies traffic that should receive common treatmentUsed to assign traffic to output queues

Loss priorityIdentifies the priority the router should give to dropping a packetUsed to select the drop profile used in the RED process


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5 Copyright 2009 Juniper Networks, Inc. www.juniper.net

Scheduler/Shaper/REDAdaptive Shaper/Virtual

Channels

COS PROCESSING

Forwarding Class/Loss Priority

BAClassifier

Policing(Ingress)

RewriteMarker

MultifieldClassifier

Fabric

Ingress

Egress

ForwardingPolicy

Policing(Egress)



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FORWARDING CLASSES All traffic transiting the router is associated with a forwarding class

Called ordered aggregates in DiffServ terminology Affects forwarding, scheduling, and marking

The forwarding class and loss priority serve to define the nodesPHB for a particular packet

Four categories

Best effort, assured forwarding, expedited forwarding, and networkcontrolM-series platforms support four forwarding classesT-series platforms support up to eight forwarding classes for finergranularity, that is, EF, EF1, and EF2 instead of just EFForwarding classes are roughly analogous to queues

Classifiers map traffic to a forwarding class at ingressMultifield and behavior aggregate classification is supported


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TRAFFIC CLASSIFICATION

Classifiers map traffic to a forwarding class at ingressMultifield classifiers (firewall filters) are normally used at thenetworks edge

Able to match on protocol, port, addresses, and so forthBehavior aggregate typically used in networks core

Computationally efficient when compared to multifield classificationOptions include:

DiffServ code pointsIPv4 precedence bits

Classifier

Bronze(BE)

Silver(EF)

Control(NC)

Packet Aacket Backet C

IEEE 802.1p bits MPLS EXP bits


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LOSS PRIORITYEach packet is associated with a loss priority during classificationor policing

Action modifier in a multifield classifier or the interpretation of abehavior aggregate pattern

A policer action for data in excess of the profile

Loss priority is used to influence probability of RED drops within a

given forwarding classSimilar in function to ATMs CLP or Frames DE

Marker rewrite often required to convey loss-priority status betweenrouters

Classifier

Bronze(LP = 0)

Packet A

Bronze(LP = 1)

Packet B

Aggressive RED

In PolicerProfile

Out ofPolicerProfile

Low Loss Priority

High Loss

Priority

Mild RED


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Policy can be used to select the forwarding next hopfor traffic associated with a particular forwarding class

Facilitates CoS-based forwarding (CBF) In this example, BE traffic is directed over the D E links

using policy at R2:

COS AND FORWARDING POLICY

A B C F

D EBE Packet EF Packet

R1 R2

R3

R4

CBF in place at R2 for the BE FC


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CLASSIFICATION OVERVIEW

In-the-box applicationsMultifield classifierNo BA rewrite

Across-the-network applicationsMultifield classifier at edgeBA in core

Data (NoBA)

Data (NoBA) Data (NoBA)

Data BA Data (NoBA)

fe-0/0/0 fe-0/0/0

se-1/0/0


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MULTIFIELD CLASSIFIERS

Data (NoBA) Data (NoBA)

se-1/0/0

firewall {family inet {

filter apply-cos-markings {term admin {

from {source-address {

192.168.200.0/25;}

}then {

forwarding-class expedited-forwarding;accept;

}}term all-other-traffic {

then accept;}

}}

}

interfaces {se-1/0/0 {

unit 0 {family inet {

filter {input apply-cos-markings;

}}

}}

}


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BEHAVIOR AGGREGATES

class-of-service {interfaces {

fe-0/0/0 {unit 0 {

rewrite-rules {inet-precedence default;

}}

}

}}

Data (NoBA) Data BA Data(NoBA)

fe-0/0/0 fe-0/0/0

class-of-service {interfaces {

fe-0/0/0 {unit 0 {

classifiers {inet-precedence default;

}}

}

}}


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REWRITE MARKERS

Marker rewrite alters packet fields to accommodate BA classification indownstream nodes

Support for IP precedence, DSCP, MPLS EXP, and IEEE 802.1P rewrite tables

One rewrite operation per logical unit per egress; simultaneous rewrite of multipleheaders is possible in some releases

Able to perform Layer 2-to-Layer 3 (and vice versa) mappings for end-to-end CoS

R1(Edge)

Packet

DSCP = 0001001

Multifield ClassifierAssigns Traffic to the BE

class

Packet

DSCP = 000000

DSCP Rewrite Table AltersDSCP Coding for BE Class

DSCP BA Classifier forBE Traffic

R2(Core)


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JUNOS SOFTWARE COS DEFAULTS

The lack of an explicit CoS configuration yields the following

behavior:

Default association of the BE, EF, AF, and NC forwarding classeswith queues 0 3 respectively

Default scheduler for BE and NC traffic95% BE, 5% NC, both linked to default WRED profile regardless ofTCP and loss-priority flags

Buffer depth set to equal WRR weight (95% and 5% respectively)


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POLICERSfirewall {

policer admin-traffic-policer {if-exceeding {

bandwidth-limit 1m;burst-size-limit 3k;

}then forwarding-class best-effort;

}

family inet {filter apply-cos-markings {

term admin {from {

source-address {192.168.200.0/25;

}}then {

policer admin-traffic-policer;forwarding-class expedited-forwarding;accept;

}}term all-other-traffic {

then accept;}

}}

}

Policer

Expedited Forwarding

Conforming Traffic Best Effort

Out-of-Profile Traffic


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QUEUEING

Overview:Default of 4 queues (0 3)Forwarding classes map toqueues

Default queue/forwarding classassociations: 0: best-effort 1: expedited-forwarding 2: assured-forwarding

3: network-control

Queue0

Queue1

Queue2

Queue3

Scheduler Map


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FORWARDING CLASS DEFINITION

To associate a forwarding class with a queue:set class-of-service forwarding-classes queue number forwarding-class-name

Examples:[edit]lab@London# set class-of-service forwarding-classes queue 4 very-important-data

[edit]lab@London# set class-of-service forwarding-classes queue 0 unimportant-data

[edit]lab@London# commit commit complete

[edit]

lab@London# run show class-of-service forwarding-class Forwarding class Queueunimportant-data 0expedited-forwarding 1assured-forwarding 2network-control 3very-important-data 4


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SCHEDULING OVERVIEW

Several components toscheduling:

Priority Transmission rate Buffer size RED configuration

Priority and transmissionrate define the orderBuffer size and REDconfiguration define howpackets are stored anddropped

Queue0

Queue1

Queue2

Queue3

Scheduler Map


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QUEUE PRIORITY ON J-SERIES ROUTERS

Queues are serviced in priorityorder:

HighMedium high

Medium lowLowL M-L M-H H

Scheduler Map

15

3 2 46

462315

*

* - exceedingtransmission rate


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SCHEDULER DEFINITION

Configure schedulers under [edit class-of-serviceschedulers]

Example:[edit class-of-service schedulers]lab@HongKong# set sched-best-effort transmit-rate percent 40

[edit class-of-service schedulers]lab@HongKong# set sched-best-effort buffer-size percent 40

[edit class-of-service schedulers]lab@HongKong# set sched-best-effort priority low

[edit class-of-service schedulers]lab@HongKong# showsched-best-effort {

transmit-rate percent 40;buffer-size percent 40;priority low;

}


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SCHEDULER MAP DEFINITION

Scheduler maps associate schedulers with queues Configured under [edit class-of-service scheduler-

maps]

Example:[edit class-of-service scheduler-maps]lab@HongKong# set class-example forwarding-class best-effort scheduler sched-best-effort

[edit class-of-service scheduler-maps]lab@HongKong# set class-example forwarding-class network-control scheduler sched-network-control

[edit class-of-service scheduler-maps]lab@HongKong# set class-example forwarding-class admin scheduler sched-admin

[edit class-of-service scheduler-maps]lab@HongKong# show class-example {

forwarding-class best-effort scheduler sched-best-effort;forwarding-class network-control scheduler sched-network-control;forwarding-class admin scheduler sched-admin;

}


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APPLYING A SCHEDULER MAP TO AN INTERFACE

Scheduler maps must be associated with outbound interfacesunder [edit class-of-service interfaces]

Wildcards are allowed for interface names and unitsPer-unit scheduling requires per-unit-scheduler in the interfaceconfiguration under [edit interfaces]

Example:[edit class-of-service interfaces]lab@HongKong# set se-1/0/0 scheduler-map class-example

[edit class-of-service interfaces]lab@HongKong# set fe-* scheduler-map class-example

[edit class-of-service interfaces]lab@HongKong# show se-1/0/0 {

scheduler-map class-example;}fe-* {

scheduler-map class-example;}


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EXAMPLE: TOPOLOGY AND GOALS

fe-2/0/1 fe-2/0/1se-1/0/0 se-1/0/0

r1 r2Classification Rules:Traffic to/from professors(192.168.25.64/26) should be placedin the professor forwarding class.Traffic to/from students

(192.168.25.128/25) should be placedin the student forwarding class, providedthe traffic from the students doesnt

exceed 1Mb/s.Traffic from students in excess of 1Mb/sshould be placed in the best-effortforwarding class.

Queues:0: best-effort1: students2: professors3: network-control

Scheduling Rules:network-control traffic should be giventhe highest priority and 5% of theavailable bandwidth.Traffic from professors should be giventhe next-highest priority (medium-high)and be allocated 50% of the bandwidth.They should be allowed to use leftoverbandwidth.Traffic from students should be given thenext-highest priority and allocated 40%of the bandwidth. They should beallowed to use leftover bandwidth.best-effort traffic should be given thelowest priority and allocated 5% of thebandwidth. They should not be allowedto use extra bandwidth.


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EXAMPLE: R1 INGRESS MULTIFIELD CLASSIFIER

then {

forwarding-class professors;accept;}

}term from-students {


192.168.25.128/26;}

}then {

policer student-policer;forwarding-class students;accept;

}}term default {

then accept;}

}}}




}}

}}

}

firewall {policer student-policer {if-exceeding {

bandwidth-limit 1m;burst-size-limit 28125;

}then forwarding-class best-effort;

}family inet {

filter apply-cos-markings {term from-professors {


192.168.25.64/26;}

}


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EXAMPLE: R2 INGRESS MULTIFIELD CLASSIFIER

term to-students {

from {destination-address {192.168.25.128/26;

}}then {

forwarding-class students;accept;

}}term default {

then accept;}

}}

}




}}

}}

}firewall {family inet {

filter apply-cos-markings {term to-professors {

from {destination-address {

192.168.25.64/26;}

}then {forwarding-class professors;accept;

}}


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EXAMPLE: FORWARDING CLASS, BA,AND SCHEDULER

schedulers {sched-network-control {

transmit-rate percent 5;buffer-size percent 5;priority high;

}sched-professors {

transmit-rate percent 50;buffer-size percent 50;priority medium-high;

}sched-students {

transmit-rate percent 40;buffer-size percent 40;priority medium-low;

}sched-best-effort {

transmit-rate percent 5 exact;buffer-size percent 5;priority low;

}}

}

class-of-service {forwarding-classes {

queue 1 students;queue 2 professors;

}interfaces {

fe-2/0/1 {scheduler-map professor-student-scheduler;unit 0 {

classifiers {inet-precedence default;

}

rewrite-rules {inet-precedence default;}

}}se-1/0/0 {

scheduler-map professor-student-scheduler;}

}scheduler-maps {

professor-student-scheduler {

forwarding-class network-control scheduler sched-network-control;forwarding-class professors scheduler sched-professors;forwarding-class students scheduler sched-students;forwarding-class best-effort scheduler sched-best-effort;

}}


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USEFUL COMMANDS (1 OF 2)

show class-of-service interfaceinterface

show interfaces interface detaillab@London> show interfaces fe-2/0/1 detail [...]Egress queues: 8 supported, 8 in use

Queue counters: Queued packets Transmitted packets Dropped packets0 best-effort 1 1 01 students 0 0 02 professors 0 0 03 network-cont 0 0 0

lab@London> show class-of-service interface fe-2/0/1 Physical interface: fe-2/0/1, Index: 142Queues supported: 8, Queues in use: 4

Scheduler map: professor-student-scheduler, Index: 15041Input scheduler map: , Index: 3

Logical interface: fe-2/0/1.0, Index: 68Object Name Type IndexRewrite ipprec-default ip 29Classifier ipprec-default ip 11


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USEFUL COMMANDS (2 OF 2)

show interfaces queue interfacelab@London> show interfaces queue fe-2/0/1 Physical interface: fe-2/0/1, Enabled, Physical link is Up

Interface index: 142, SNMP ifIndex: 62Forwarding classes: 8 supported, 8 in useEgress queues: 8 supported, 8 in useQueue: 0, Forwarding classes: best-effort

Queued:Packets : 1 0 ppsBytes : 42 0 bps

Transmitted:Packets : 1 0 ppsBytes : 42 0 bpsTail-dropped packets : 0 0 ppsRED-dropped packets : 0 0 pps

Low : 0 0 ppsMedium-low : 0 0 ppsMedium-high : 0 0 ppsHigh : 0 0 pps

RED-dropped bytes : 0 0 bpsLow : 0 0 bpsMedium-low : 0 0 bpsMedium-high : 0 0 bpsHigh : 0 0 bps

Queue: 1, Forwarding classes: studentsQueued:

Packets : 0 0 ppsBytes : 0 0 bps

[...]


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TROUBLESHOOTING HINTS

Hints: Add a counter to an existing multifield classifierUse monitor traffic to look for behavioraggregate markings in the headers of traffic destined

to the router Add an input firewall filter that counts traffic assignedto each forwarding class, matches on BA fields, orboth

Look for drops in show interfaces queue outputUse show interfaces queue to see if a queue isexceeding its transmission rate


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COS-BASED FORWARDING. EJEMPLORouter A has two routes to destination 10.255.71.208 on Router D. Oneroute goes through Router B, and the other goes through Router C.

Configure Router A with CBF to select Router B for queue 0 and queue 2,and Router C for queue 1 and queue 3.

[edit class-of-service]forwarding-policy {

next-hop-map my_cbf {forwarding-class be {

next-hop ge-2/0/0.0;}forwarding-class ef {

next-hop so-0/3/0.0;

}forwarding-class af {

next-hop ge-2/0/0.0;}forwarding-class nc {

next-hop so-0/3/0.0;}

}}

classifiers {inet-precedence inet {

forwarding-class be {loss-priority low code-points [ 000 100 ];

}forwarding-class ef {

loss-priority low code-points [ 001 101 ];}forwarding-class af {

loss-priority low code-points [ 010 110 ];}forwarding-class nc {

loss-priority low code-points [ 011 111 ];}

}}

[edit policy-options]policy-statement cbf {

from {route-filter 10.255.71.208/32 exact;

}then cos-next-hop-map my_cbf;

}


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VOIP CASE STUDY TOPOLOGY

General notes: Adapted from the example used in the JNCIE certification preparationguideConfiguration and operational analysis is unidirectional (fromsubscriber to PABX)

Simplifies and reduces the size of configuration examplesYields one-way CoS! A similar set of configuration statements needed toprovide CoS in the return direction

San Jose Montreal

Denver

AmsterdamHong Konglo0: 192.168.16.1

lo0: 192.168.20.1 lo0: 192.168.40.1

lo0: 192.168.56.1

lo0: 192.168.32.1

Service Provider

PABX Dataandset Data

10.222.x/24

CoS configured in this direction only

Ingress

Transit

Egress


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VOIP CASE STUDY CRITERIA: INGRESS

Use CoS to support VoIP, conventional Internet, and control traffic received

from a customerClassification and policingVoIP SIP signaling uses TCP/UDP port 5060RTP media channels use UDP with ports in the range of 16,000 16,500Classify all VoIP traffic as expedited forwardingClassify IP precedence 6 or 7 as network control

Classify all remaining IP precedence 0 traffic as best effortPolice BE traffic to 1 Mbps with a 3000-byte burst; mark excess traffic as highloss priority

Scheduling and congestion controlSchedule VoIP traffic as high priority with at least 20 Mbps of capacity; limitmaximum delay to 200 millisecondsSchedule BE traffic with low priority and limit to 1 MbpsConfigure WRED for the BE class so that a greater percentage of high losspriority traffic is discarded; only TCP traffic is subjected to WRED

Marker rewriteRewrite the DSCP marker to accommodate BA classification; ensure that losspriority for the EF forwarding class is coupled between chassis


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INGRESS NODE MULTIFIELD CLASSIFIER[edit firewall family inet filter mf-classify]lab@San_Jose-3# show term 1 {

from {protocol [ udp tcp ];port 5060;

}then forwarding-class expedited-forwarding;

}term 2 {

from {

protocol udp;port 16000-16500;}then forwarding-class expedited-forwarding;

}term 3 {

from {precedence routine;

}then {

policer police-be;forwarding-class best-effort;

}}term 4 {

then accept;}

Precedence 0 traffic directed topolicer and classified as BE

Traffic associated with VoIP isclassified as EF and accepted

Network control accepted and classified byipprec-compatibility


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INGRESS NODE SCHEDULING/WRED

Code PointClassifier


Policing(Ingress)

ForwardingPolicy

Rewrite/

Marker

Scheduler/

WRED

Policing

(Egress)

Forwarding Class/

Loss Priority


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CONFIGURING SCHEDULERSDefine a scheduler for all forwarding classes that are in effect

A network control scheduler should always be in effect to ensure thatcontrol protocols are not starved

[edit class-of-service]lab@San_Jose# show schedulers be-scheduler {

transmit-rate 1m exact;priority low;drop-profile-map loss-priority low protocol tcp drop-profile low-red;drop-profile-map loss-priority high protocol tcp drop-profile high-red;

}ef-scheduler {

transmit-rate 20m;buffer-size temporal 200000;priority high;

}nc-scheduler {

transmit-rate percent 5;priority low;

}

In this case study, buffer depth isset for the EF class only. Delay ismeasured in microseconds.


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DEFINING WRED DROP PROFILES

Two drop profiles are required for the BE class in this example:The low-red profile affects TCP traffic with low loss priority10% drop probability at 80% queue fill

The high-red profile affects TCP traffic with high loss priority10% drop probability at 50% queue fill

Drop profiles are referenced within a scheduler stanza on aforwarding class, TCP status, and loss-priority basis

[edit class-of-service]lab@San_Jose# show drop-profiles low-red {

fill-level 80 drop-probability 10;}high-red {

fill-level 50 drop-probability 10;}


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LINK SCHEDULERS TO CLASSES/INTERFACES

[edit class-of-service]lab@San_Jose# show scheduler-maps voip-case {

forwarding-class best-effort scheduler be-scheduler;forwarding-class expedited-forwarding scheduler ef-scheduler;forwarding-class network-control scheduler nc-scheduler;

}

[edit class-of-service]lab@San_Jose# show interfaces fe-0/0/1 {

scheduler-ma p voip-case;}

Define a scheduler map to link forwarding classes to

schedulers

Place schedulers into effect on egress interfaces bylinking them to a scheduler map

Schedulers are applied at the physical device level


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INGRESS NODE REWRITE TABLE



Policing(Ingress)

ForwardingPolicy

Rewrite/

Marker

Scheduler/

WREDPolicing

(Egress)

Forwarding Class/

Loss Priority


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CONFIGURING DSCP REWRITE TABLEDefault DSCP rewrite table does not communicate loss priority forBE traffic

The voip-dscp-rewrite table imports default settings and definesa code point for BE traffic with high loss priority:

The voip-dscp-rewrite table is linked to the egress interface atthe ingress node:

[edit class-of-service rewrite-rules dscp voip-dscp-rewrite]lab@San_Jose# show import default;

forwarding-class best-effort {loss-priority high code-point 000001;

}

[edit class-of-service]lab@San_Jose# show interfaces fe-0/0/1 scheduler-map voip-case;unit 0 {

rewrite-rules {dscp voip-dscp-rewrite;

}

}

Prepopulates new table with values fromthe default DSCP rewrite table


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INGRESS COS CONFIGURATION UNIDIRECTIONAL (1OF 2)

[edit class-of-service]lab@San_Jose# show drop-profiles {

low-red {fill-level 80 drop-probability 10;}high-red {


}interfaces {

fe-0/0/1 {scheduler-map voip-case;unit 0 {


}}

}}rewrite-rules {

dscp voip-dscp-rewrite {import default;forwarding-class best-effort {

loss-priority high code-point 000001;}

}}. . .


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INGRESS COS CONFIGURATION UNIDIRECTIONAL (2OF 2)

The ingress nodes multifield classifier and policer configuration isshown on a previous slide

. . .scheduler-maps {

voip-case {forwarding-class best-effort scheduler be-scheduler;forwarding-class expedited-forwarding scheduler ef-scheduler;forwarding-class network-control scheduler nc-scheduler;

}}schedulers {

be-scheduler {transmit-rate 1m exact;priority low;

drop-profile-map loss-priority low protocol tcp drop-profile low-red;drop-profile-map loss-priority high protocol tcp drop-profile high-red;}ef-scheduler {


}nc-scheduler {


}}


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VOIP CASE STUDY CRITERIA: TRANSIT/EGRESS

Use CoS to support VoIP, conventional Internet, and control traffic

received from an upstream nodeBA classification

Configure DSCP-based BA classification compatible with ingress nodeclassification

Scheduling and congestion controlSchedule VoIP traffic as high priority with at least 20 Mbps of capacitySchedule BE traffic with low priority, and limit this traffic to 1 MbpsConfigure RED profiles for BE traffic that discriminate on loss priority andTCP status flags

Marker rewriteRewrite the DSCP marker to accommodate BA classification indownstream nodes; ensure that loss priority for the EF forwarding class iscoupled between chassis


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TRANSIT/EGRESS NODE BA CLASSIFICATION



Policing(Ingress)

ForwardingPolicy

Rewrite/

Marker

Scheduler/

WRED

Policing

(Egress)

Forwarding Class/

Loss Priority


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CONFIGURING DSCP CLASSIFICATION TABLE

The voip-dscp-classify table defines code points for BE

traffic with high/low loss priorityThe DSCP classifiers must match the DSCP rewrite values in effectat the upstream node

Link the voip-dscp-classify table to the i ng ress interface attransit/egress nodes:

[edit class-of-service classifiers dscp voip-dscp-classifier]lab@Denver# show

import default;forwarding-class best-effort {

loss-priority high code-points 000001;}

[edit class-of-service]lab@Denver# show interfaces fe-0/0/1 unit 0 {

classifiers {dscp voip-dscp-classifier;

}}

Prepopulates new table with values fromthe default DSCP classifier table


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TRANSIT/EGRESS NODE SCHEDULERS/WRED



Policing(Ingress)

ForwardingPolicy

Rewrite/

MarkerScheduler /

WRED

Policing

(Egress)

Forwarding Class/

Loss Priority


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CONFIGURING SCHEDULERSTransit and egress nodes use the same scheduler configuration asthe ingress node

CoS designs must ensure consistent traffic handling among all nodesin the path

[edit class-of-service]lab@Denver# show schedulers be-scheduler {

transmit-rate 1m exact;priority low;drop-profile-map loss-priority low protocol tcp drop-profile low-red;drop-profile-map loss-priority high protocol tcp drop-profile high-red;

}ef-scheduler {


}nc-scheduler {


}


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DEFINING WRED DROP PROFILES

[edit class-of-service]

lab@Denver# show drop-profiles low-red {

fill-level 80 drop-probability 10;}high-red {

fill-level 50 drop-probability 10;

}

Transit and egress nodes use the same drop profilesconfigured at the ingress node

CoS designs are contingent on consistent and predictable traffic handling among all nodes in the path


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[edit class-of-service]lab@Denver# show scheduler-maps voip-case {

forwarding-class best-effort scheduler be-scheduler;forwarding-class expedited-forwarding scheduler ef-scheduler;forwarding-class network-control scheduler nc-scheduler;

}[edit class-of-service]lab@Denver-3# show interfaces fe-0/0/1 {

unit 0 {classifiers {

dscp voip-dscp-classifier;}

}}so-0/1/1 {

scheduler-map voip-case;}

LINK SCHEDULERS TO CLASSES AND INTERFACES A scheduler map links forwarding classes to schedulers and toegress interfaces


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TRANSIT NODE MARKING



Policing(Ingress)

ForwardingPolicy

Rewrite/

Marker

Scheduler/

WREDPolicing

(Egress)

Forwarding Class/

Loss Priority


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CONFIGURING TRANSIT NODE MARKINGTransit nodes have the same DSCP rewrite table as the ingressnode

Applied to transit nodes egress interface

No egress conditioning is required in this case study

[edit class-of-service]lab@Denver# show rewrite-rules dscp voip-dscp-rewrite {

import default;forwarding-class best-effort {

loss-priority high code-point 000001;}

}

[edit class-of-service]

lab@Denver# show interfaces so-0/1/1 scheduler-map voip-case;unit 0 {


}}

TRANSIT/EGRESS NODE COS CONFIGURATION


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TRANSIT/EGRESS NODE COS CONFIGURATION(1 OF 2)

[edit class-of-service]lab@Denver# show classifiers {

dscp voip-dscp-classifier {import default;forwarding-class best-effort {

loss-priority high code-points 000001;}

}}drop-profiles {

low-red {fill-level 80 drop-probability 10;

}high-red {


}interfaces {

fe-0/0/1 {unit 0 {classifiers {

dscp voip-dscp-classifier;}

}}

. . .

. . .so-0/1/1 {

scheduler-map voip-case;unit 0 {


}}

}}. . .


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GENERATING TEST DATATraffic is generate from the Hong-Kong station to confirm properclassification

Pings generate traffic to confirm BE classificationTelnet to port 5060 confirms EF (VoIP) classification

lab@Hong_Kong> ping 192.168.32.1 count 5 PING 192.168.32.1 (192.168.32.1): 56 data bytes

64 bytes from 192.168.32.1: icmp_seq=0 ttl=252 time=0.642 ms64 bytes from 192.168.32.1: icmp_seq=1 ttl=252 time=0.541 ms64 bytes from 192.168.32.1: icmp_seq=2 ttl=252 time=0.526 ms64 bytes from 192.168.32.1: icmp_seq=3 ttl=252 time=0.519 ms64 bytes from 192.168.32.1: icmp_seq=4 ttl=252 time=0.525 ms

--- 192.168.32.1 ping statistics ---5 packets transmitted, 5 packets received, 0% packet lossround-trip min/avg/max/stddev = 0.519/0.551/0.642/0.046 ms

lab@Hong_Kong> telnet 192.168.32.1 port 5060 Trying 192.168.32.1...telnet: connect to address 192.168.32.1: Connection refusedtelnet: Unable to connect to remote host

Connection failure is expected


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CONFIRMING INGRESS CLASSIFICATION Adding a count or log action modifier to a multifield classifier canassist in troubleshooting

In this example, the MF classifier at San_Jose works as intended:

lab@San_Jose> show interfaces fe-0/0/1 detail | find Queue CoS queues : 4 supportedHold-times : Up 0 ms, Down 0 msCurrent address: 00:90:69:6d:98:01, Hardware address: 00:90:69:6d:98:01Last flapped : 2003-11-22 19:49:35 UTC (00:00:14 ago)Statistics last cleared: 2003-11-22 19:49:23 UTC (00:00:26 ago)Traffic statistics:

Input bytes : 556 0 bpsOutput bytes : 644 0 bpsInput packets: 7 0 ppsOutput packets: 8 0 pps

Queue counters: Queued packets Transmitted packets Dropped packets0 best-effort 5 5 01 expedited-fo 1 1 02 assured-forw 0 0 03 network-cont 2 2 0

Active alarms : LINKActive defects : LINK

. . .


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CONFIRMING INGRESS POLICING

Rapid pings with large packet sizes exceed the BE policer profile

Excess traffic is marked, not discarded in this example

lab@Hong_Kong> ping 192.168.32.1 rapid size 40000 count 20 PING 192.168.32.1 (192.168.32.1): 40000 data bytes....................--- 192.168.32.1 ping statistics ---20 packets transmitted, 0 packets received, 100% packet loss

lab@SanJose> show firewall Filter: __default_bpdu_filter__

Filter: mf-classifyPolicers:Name Packetspolice-be-3 480


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lab@San_Jose> show interfaces queue fe-0/0/1 Physical interface: fe-0/0/1, Enabled, Physical link is Up

Interface index: 129, SNMP ifIndex: 32Forwarding classes: 4 supported, 4 in useQueues: 4 supported, 4 in useQueue: 0, Forwarding classes: best-effort

Queued:Packets : 560 0 pps

Bytes : 811360 0 bpsTransmitted:Packets : 340 0 ppsBytes : 486120 0 bpsTail-dropped packets : 0 0 ppsRED-dropped packets : 220 0 pps

Low, non-TCP : 40 0 ppsLow, TCP : 0 0 ppsHigh, non-TCP : 180 0 ppsHigh, TCP : 0 0 pps

RED-dropped bytes : 330000 0 bpsLow, non-TCP : 60000 0 bpsLow, TCP : 0 0 bpsHigh, non-TCP : 270000 0 bpsHigh, TCP : 0 0 bps

. . .

CONFIRMING INGRESS SCHEDULERRapid pings exceed 1-Mbps limit of BE scheduler


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DISPLAYING FC-TO-QUEUE MAPPINGS

This display shows the default FC-to-queue mappings Additional mappings possible to support T-series systems using morethan four queues

lab@Denver> show class-of-service forwarding-class

Forwarding class Queuebest-effort 0expedited-forwarding 1assured-forwarding 2network-control 3


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CONFIRMING TRANSIT CLASSIFICATION

Displaying queue statistics for a transit nodes egress interface

confirms BA classificationThe counters match the results of ingress classification

lab@Denver> show interfaces so-0/1/1 detail | find Queue CoS queues : 4 supportedLast flapped : 2003-11-20 16:29:27 UTC (00:32:40 ago)

Statistics last cleared: 2003-11-20 17:00:16 UTC (00:01:51 ago)Traffic statistics:


Queue counters: Queued packets Transmitted packets Dropped packets

0 best-effort 5 5 01 expedited-fo 1 1 02 assured-forw 0 0 03 network-cont 39 39 0

SONET alarms : NoneSONET defects : None. . .


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DISPLAYING THE DSCP CLASSIFIERlab@Denver> show class-of-service classifier ? Possible completions:

Execute this command

name Name of classifiertype Type of classifier| Pipe through a command

lab@Denver> show class-of-service classifier name voip-dscp-classifier Classifier: voip-dscp-classifier, Code point type: dscp, Index: 62709

Code point Forwarding class Loss priority000000 best-effort low

000001 best-effort high000010 best-effort low000011 best-effort low000100 best-effort low000101 best-effort low000110 best-effort low000111 best-effort low001000 best-effort low

001001 best-effort low001010 assured-forwarding low001011 best-effort low001100 assured-forwarding high001101 best-effort low001110 assured-forwarding high001111 best-effort low

. . .


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DISPLAYING THE DSCP REWRITE TABLE

lab@Denver> show class-of-service rewrite-rule ?

Possible completions: Execute this commandname Name of rewrite ruletype Type of rewrite rule| Pipe through a command

lab@Denver> show class-of-service rewrite-rule name voip-dscp-rewrite

Rewrite rule: voip-dscp-rewrite, Code point type: dscp, Index: 62398Forwarding class Loss priority Code pointbest-effort low 000000best-effort high 000001expedited-forwarding low 101110expedited-forwarding high 101110assured-forwarding low 001010assured-forwarding high 001100network-control low 110000network-control high 111000


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DISPLAYING THE SCHEDULER MAPlab@Denver> show class-of-service scheduler-map ? Possible completions:

Execute this command Name of scheduler map| Pipe through a command

lab@Denver> show class-of-service scheduler-map voip-case Scheduler map: voip-case, Index: 56711

Scheduler: be-scheduler, Forwarding class: best-effort, Index: 4154Transmit rate: 1000000 bps, Rate Limit: exact, Buffer size: remainder, Priority: low

Drop profiles:Loss priority Protocol Index NameLow non-TCP 1 Low TCP 40376 low-redHigh non-TCP 1 High TCP 53001 high-red

Scheduler: ef-scheduler, Forwarding class: expedited-forwarding, Index: 5046

Transmit rate: 20000000 bps, Rate Limit: none, Buffer size: 200 us, Priority: highDrop profiles:

Loss priority Protocol Index NameLow non-TCP 1 Low TCP 1 High non-TCP 1 High TCP 1

. . .


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DISPLAYING INTERFACE COS SETTINGSlab@San_Jose> show class-of-service interface fe-0/0/1 Physical interface: fe-0/0/1, Index: 129

Queues supported: 4, Queues in use: 4Scheduler map: voip-case, Index: 56711

Logical interface: fe-0/0/1.0, Index: 68Object Name Type IndexRewrite voip-dscp-rewrite dscp 62398Rewrite exp-default exp 2

Classifier ipprec-compatibility ip 5

lab@Denver> show class-of-service interface fe-0/0/1 Physical interface: fe-0/0/1, Index: 129Queues supported: 4, Queues in use: 4

Scheduler map: , Index: 1

Logical interface: fe-0/0/1.0, Index: 67Object Name Type IndexRewrite exp-default exp 2Classifier voip-dscp-classifier dscp 62709

Egress interface CoS settings

Ingress interface CoS settings


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DISPLAYING DROP PROFILES

lab@San_Jose> show class-of-service drop-profile ?Possible completions:

Execute this command Name of drop profile| Pipe through a command

lab@San_Jose> show class-of-service drop-profile Drop profile: , Type: discrete, Index: 1

Fill level Drop probability100 100

Drop profile: high-red, Type: discrete, Index: 53001Fill level Drop probability

50 10Drop profile: low-red, Type: discrete, Index: 40376

Fill level Drop probability

80 10


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DISPLAYING FORWARDING TABLE COS SETTINGSlab@Denver> show class-of-service forwarding-table ? Possible completions:

Execute this commandclassifier Show classifier informationdrop-profile Show RED drop profilepolicer Show policerrewrite-rule Show rewrite informationscheduler-map Show scheduler mapshaper Show shaper| Pipe through a command

lab@Denver> show class-of-service forwarding-table classifier mapping Table Index/Interface Index Q num Table typefe-0/0/1.0 69 62709 DSCPso-0/1/1.0 70 5 IPv4 precedence

lab@Denver> show class-of-service forwarding-table scheduler-map Interface: fe-0/0/0 (Index: 128, Map index: 1, Num of queues: 2):

Entry 0 (Scheduler index: 2, Queue #: 0):Tx rate: 0 Kb (95%), Buffer size: 95 percentPLP high: 1, PLP low: 1, TCP PLP high: 1, TCP PLP low: 1

Entry 1 (Scheduler index: 4, Queue #: 3):Tx rate: 0 Kb (5%), Buffer size: 5 percentPLP high: 1, PLP low: 1, TCP PLP high: 1, TCP PLP low: 1

. . .


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DISPLAYING COS QUEUING INFORMATION

lab@Denver> show interfaces queue so-0/1/1 Physical interface: so-0/1/1, Enabled, Physical link is Up

Interface index: 133, SNMP ifIndex: 27Forwarding classes: 4 supported, 4 in useQueues: 4 supported, 4 in useQueue: 0, Forwarding classes: best-effort

Queued:Packets : 5 0 ppsBytes : 420 0 bps

Transmitted:Packets : 5 0 ppsBytes : 445 0 bpsTail-dropped packets : 0 0 ppsRED-dropped packets : 0 0 pps

Low, non-TCP : 0 0 ppsLow, TCP : 0 0 ppsHigh, non-TCP : 0 0 pps

High, TCP : 0 0 ppsRED-dropped bytes : 0 0 bpsLow, non-TCP : 0 0 bpsLow, TCP : 0 0 bpsHigh, non-TCP : 0 0 bpsHigh, TCP : 0 0 bps

. . .

DISPLAYING COS RELATED INTERFACE COUNTERS


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DISPLAYING COS-RELATED INTERFACE COUNTERS

lab@Denver> show interfaces so-0/1/1 extensive Physical interface: so-0/1/1, Enabled, Physical link is Up

. . .CoS queues : 4 supported

Last flapped : 2003-11-20 16:29:27 UTC (02:33:14 ago)Statistics last cleared: 2003-11-20 17:00:16 UTC (02:02:25 ago)Traffic statistics:


. . .Queue counters: Queued packets Transmitted packets Dropped packets

0 best-effort 544 544 01 expedited-fo 2 2 02 assured-forw 0 0 03 network-cont 2343 2343 0

. . .Packet Forwarding Engine configuration:

Destination slot: 0, PLP byte: 1 (0x00)CoS transmit queue Bandwidth Buffer Priority Limit

% bps % bytes0 best-effort 0 1000000 50 0 low exact1 expedited-forwarding 12 20000000 0 200 high none3 network-control 5 7776000 50 0 low none

. . .


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