alcplus2 and alcplus2e qos_2

7/18/2019 ALCPlus2 and ALCPlus2e QoS_2

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Calidad de servicio (QoS) es una característica esencial cuando la red Ethernet debe llevar, con excepción de

los paquetes de datos, también aplicaciones de tiempo interactiva y real

!plicaciones en tiempo real (por e"emplo, #o$%) tienen requisitos estrictos en términos de ancho de banda,

latencia y "itter %or lo tanto, cuando el rendimiento de la red se vuelve insu&iciente para 'arantiar el transporte

de todo el tr&ico de Ethernet, los mecanismos de QoS se utilian para distin'uir entre los di&erentes tipos de

tr&ico, dando alta prioridad a los paquetes críticos (tiempo real) y la reducción del ancho de banda dedicado a

paquetes de datos

QoS Mecanismo:

QoS en los equipos !*C %lus+ se pueden activar en el Capa +, en el Capa , o ambos, dependiendo de los

requerimientos del usuario-

$EEE ./+0p QoS (Capa + Calidad de Servicio), donde el tr&ico se prioria de acuerdo con los tres bits del

1!2 ./+0Q

$%v3 1oS (Capa 1ipo de Servicio de la cabecera $% v3), donde el tr&ico se prioria de acuerdo con los seis

bits del 1oS (4SC%)

$%v5 1oS (Capa 1ipo de Servicio de la cabecera $% v5) donde el tr&ico se prioria de acuerdo con los seis

bits del 1oS (4SC%)

Cuando se activan los dos mecanismos de QoS (./+0p y $%1oS), el dise6ador puede ele'ir la prioridad de

cada mecanismo de QoS (es decir ./+0p 7 $%1oS o $%1oS 7 ./+0p)

ALCPlus2 – Descripción QoS

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Scheduling:

1he inte'rated s8itch has &our queues 8here the pac9ets are stored in case o& tra&&ic con'estions 1hepriority mana'ement is done by sendin' the pac9ets on these output queues 1he tra&&ic is sent to each

queue on the basis o& its ./+0p or 1oS values 1he correspondence bet8een the ./+0p or 1oS values

and each output queue can be set via so&t8are

Output Queues of ALCplus2:

1he pac9ets on the queue can be sent on the basis o& t8o di&&erent policies (selectable via so&t8are)-: Strict %riority (S%)- ;irst all the pac9ets &rom the hi'hest priority queue are transmitted, then all the

pac9ets &rom the second queue, and so on (C!SE 0 o& the &i'ure reported belo8)

: <ei'hted =ound =obin (<==)- 1he pac9ets are sent &ollo8in' the .737+70 rule $e, &irst are

transmitted . pac9ets &rom the hi'hest priority queue, then 3 pac9ets &rom the second queue, then +

pac9ets &rom the third queue and &inally 0 pac9et &rom the lo8est priority queue (C!SE +)

: $t is also possible to use hybrid priority policies, de&inin' Queue (or Queue and Queue +) as S% and

the rest o& the queues as <== (C!SE and 3)

LowHigh

Queue 3 Queue 2 Queue 1 Queue 0

CASE 1 Strict Priority

CASE 2 8 4 2 1 WRR

CASE 3 4 2 1

CASE 4 2 1

ALCPlus2 - QoS Description




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Scheduling:

1he ;%2! has . queues 8here the pac9ets are stored in case o& tra&&ic con'estions 1he priority

mana'ement is done by sendin' the pac9ets on these output queues 1he tra&&ic is sent to each queue on the

basis o& its ./+0p or 1oS values 1he correspondence bet8een the ./+0p or 1oS values and each output

queue can be set via so&t8are

Output Queues:

1he pac9ets can be sent to the Servant (radio) based on di&&erent policies (selectable via so&t8are)-

: Strict %riority (S%)- ;irst all the pac9ets &rom the hi'hest priority queue are transmitted, then all the pac9ets

&rom the second queue and so on

ALCPlus2e - Queues and Scheduling




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<ei'hted ;air Queuein' (<;Q)- 1he pac9ets are sent on the radio &ollo8in' a rule based on the 8ei'ht

assi'ned to each Queue

Each queue >i? 8ith <;Q is 'iven a 8ei'ht (importance) <i

<;Q 'uarantees a minimum service rate to queue >i?

Ri = R * Wi / W1 ! W2 ! """ ! W#$ %R&te o' the (ueue i)

<here-

= @ rate o& the servant ( Capacity available on the A< lin9)

<i @ 8ei'ht o& the Queue ta9en in consideration

<n @ 8ei'ht o& the last Queue 8ith <;Q enabled

: $t is also possible to use Bybrid %riority %olicies, de&inin' queue by queue either Strict %riority or <;Q

ALCPlus2e - Queues and Scheduling

Bi'her %riority

*o8er %riority

Servin' %riority-

01he pac9ets present in the Queue 8ill be transmitted

8ith a =ate .D

+1he pac9ets present in the Queue 5 8ill be transmitted8ith a =ate .D

F

3F

1he pac9ets present in the Queue / 8ill be transmitted

8ith a =ate 0D

Queue Type Weight

7 WFQ 8

6 WFQ 8

WFQ 6

4 WFQ 4

3 WFQ 42 WFQ 2

1 WFQ 2

! WFQ 1

Sum of theWeights

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Ethernet L2

switch


FPGA

Queue 7Queue 6

Queue 5

Queue Tow!r

"#!"io

LA$

LA$2

LA$

%

LA$

&

The 'utput sche"u(ing po(icyis softw!re se(ect!)(e*

Strict Priority

Weighe" F!ir Queue +i,e"

Queue &

Queue 2

Queue%

Queue-

Ser.!nt

ALCplus2e IDU – Queue Architecture Revie



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Drop Types:

<hen the queue is &ull, 8e are in a con'estion situation 1his means that the resources are not enou'h to

serve all the pac9ets and there is not enou'h room in the queue &or more stora'e $n this case some pac9et

must be dropped 1here are di&&erent policy o& droppin' that can be adopted-

: &i+, $n this case the last pac9ets that come to the &ull queue are dropped (de&ault con&i'uration)

: Queue- $n this case all the queue is emptied, ie all the pac9ets present in the Queue are dropped

: Re-, =andom Early 4iscard- 8ith this policy, be&ore the Queue is &ull some pac9et belon'in' to the queue

are dropped randomly re'ardless i& they are hi'h priority tra&&ic or lo8 priority tra&&ic

: Wre-, <ei'hted =andom early 4iscard- 8ith this policy, be&ore the Queue is &ull some pac9et belon'in' to

the queue are dropped randomly ;irst are dropped the pac9ets 8ith lo8 priority and then are dropped the

pac9et o& hi'h priority

ALCPlus2e Queues and Scheduling

Gu&&er Sie-

0+. H +5 H 0+ H 0/+3 H +/3.

H 3/I5 H .0I+ Jbit

%olicy 1ype-

: Strict %riority

:<ei'hted ;air Queuein'

<;Q <ei'ht

(&or S% this &ield

does not apply)

4rop 1ype-

: 1ail

:Queue

:=ed

:<red


alcplus2 and alcplus2e qos_2

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