IPasolink 200 400 EthernetFeatures

0 iPASO200 Advanced Ethernet Functions

iPASOLINK200

Advanced Ethernet Functions Overview

1 iPASO200 Advanced Ethernet Functions © NEC Corporation 2010 Page 1

Port MAC address

1 A 00-00-00-00-00-01

4 D 00-00-00-00-00-04

MAC A

1 2 3 4

MAC Address Table

Forwarding Data Table (FDB)

FDB of iPASO200 is 32KByte

Default FDB Aging Time 300 sec

Dst MAC: A

Src MAC: D

Dst MAC: D

Src MAC: A

Basic Ethernet Switching Procedure

Frame transmission on Ethernet switch is realized by MAC address learning

MAC B MAC C MAC D 00-00-00-00-00-01

00-00-00-00-00-04


ＶＬＡＮ１０ＶＬＡＮ２０

Broadcast frame is

transmitted to all port

except received port

Broadcast frame is not

transmitted to different

VLAN group

VLAN setting

Advantages of VLAN (Virtual LAN)

Enables to make virtual group in LAN

– But communication between different VLAN group can be processed by router

Enables to divide broadcast domain

– Broadcast frame is transmitted to all port except port where broadcast frame was received when VLAN is not used

– Broadcast frame is not transmitted to different VLAN group


Port Based VLAN and Tag Based VLAN

VLAN Switch 1 2 3 4 5 6 7 8 9 10 11 12

VLAN 1 VLAN 2 VLAN 3

(VLAN ID 10)

(VLAN ID 20)

VLAN SW

1 2

3

4

6 5

1 (VLAN ID 10)

(VLAN ID 20)

2

3

4

6

5

Tag 10 Tag 20

VLAN SW

Port Based VLAN

Tag Based VLAN

iPASO200 named

it as Access VLAN type

iPASO200 named

it as Trunk VLAN type


Extended VLAN ( Q in Q)

Extended VLAN is standardized by IEEE802.1ad

VLAN tag (4byte) is stacked to Ethernet frame

iPASO200 named the extended VLAN as Tunnel VLAN

Common Network

VLAN100

VLAN100

VLAN100

VLAN100

Company A

Company A Company B

Company B

Data 100

Data 100

Data 100 200 Data 100 300

Data 100

Data 100


VLAN Tag Frame Format

Tag VLAN is standardized by IEEE802.1q

VLAN tag (4byte) is inserted to Ethernet frame

Preamble

8byte

Destination

MAC

address

(DA)

6byte

Source MAC

address

(SA)

6byte

VLAN

tag

4byte

Lengt

h /

typeﾟ

2byte

Data

46 - 1500byte

FCS

4byte

802.1q tag type

2byte

TCI field

2byte

Priority

3bit

CFI

1bit

VLAN-ID

12bit

Range: 1 - 4094

(0, 4095 reserved)


Why Jumbo Frame Support is necessary ?

1500 18

Max MTU Size = MTU1500bytes + 4 bytes VLAN Tag

Max Frame Size = 1522 Bytes

Max 1518 Bytes

1500 18 4

Max 1526 Bytes

4

Efficient Through-put for application which supports jumbo MTU size (e.g. IP-SAN)

Support Ethernet Expansion Frames like VLAN tag, QinQ, MPLS Label etc..

iPASO200 supports frame size of FE ports to 2000 Byte and GbE port to 9600 Byte

Usual

Ethernet

Frame

1500 18

Max 1522 Bytes 802.1q

Ethernet

Frame 4

Q in Q

Ethernet

Frame

Max MTU Size = 1500bytes (Ethernet Standard)

Max Frame Size = 1518bytes

Max MTU Size = MTU1500bytes + (2 x 4 bytes VLAN

Tag)

Max Frame Size = 1526 Bytes

Ethernet Header 18Bytes


VLAN Setting (1)– Types of VLAN setting at ports

Types of VLAN port supported in iPASO200 are named Access, Trunk and Tunnel

How to create Access type (port base) VLAN?

1. FE Port set to access port type VLAN

2. Modem port set to trunk type VLAN

FE Port 1:

Access

VLAN 10

Modem 1:

Trunk

VLAN 10

iPASO200

Data 100

Data Data 10

Drop

Send with VLAN 10

Default VLAN is 1 , here we set to 10 as example

Recommendation: To be used for base station with un-tag traffic


VLAN Setting (2) – Types of VLAN setting at ports

1. FE port set to trunk port type VLAN (802.1q) and un-tag frame to be access

2. Modem port set to trunk port VLAN

FE Port 2:

Access

VLAN 2

Trunk

VLAN 20

Modem 1:

Trunk

VLAN 2, 20

iPASO200

Data 100

Drop

Send with VLAN 20 Data 20

Data Send with VLAN 2

Data

Data

20

Set for Un-tag packet

Recommendation: To be used for base station with VLAN tag interface

How to create tag base type (802.1q) VLAN and also supported with un-tag traffic?

2


VLAN Setting (3) – Types of VLAN setting at ports

FE port set to tunnel port type VLAN (almost 802.1ad or Radio Hop Q in Q)

Modem port set to trunk port VLAN

All packets will be sent transparently with additional tag added on

FE Port3:

Tunnel

VLAN 30

Modem 1:

Trunk

VLAN 30

iPASO200

Add on tag VLAN 30

Add on tag VLAN30

No packets will

be drooped

Data Data 20

Data Data

20

30

30

Recommendation: To be used when required Q in Q features

How to create tunnel type ( Q in Q ) VLAN?


VLAN Setting (4) – Setting methods at Modem ports

Modem port parameter setting methods

Modem 1:

Trunk

VLAN 2,10,20,30

iPASO200

Data

Data 30

Data 20

Data 10

Data 40

Drop

2


Overall view of iPASO200 L2 Switch

L2 SW

FE2/GbE

FE1/GbE

FE3/GbE

FE4/GbE

GbE5

GbE6

Modem1

Modem 2

Trunk

VLAN

Trunk

VLAN

1.Access

VLAN

2.Trunk

VLAN

3.Tunnel

VLAN


Fault Management

– CC (Continuity Check)

– LB (Loop Back) → It corresponds to “ping” in IP.

– LT (Link Trace) → It corresponds to “trace route” in IP.

To maintain the service availability and quality for the packet networks, powerful OAM toolset is required.

Provide Fault management by

Ethernet OAM (ITU-T Y.1731 and CFM or IEEE 802.1ag).

BTS/Node-B BSC/RNC Operator A Operator B

Provider X

CC

LB

LT

Ethernet OAM

Y.1731 Performance Management not yet supported

By iPASO200

13 iPASO200 Advanced Ethernet Functions © NEC Corporation 2010

Customer Customer

Operator

Level (0-2)

Service

Provider

Level (3-5)

Customer

Level (5-7)

Operator A Operator B

1 2 3 4 5 6 8 9

Maintenance Entity Points

Maintenance Intermediate Points Maintenance Entities

Provider X

Example of Maintenance Entities


To Establish OAM connections on the Ethernet-based networks.

To understand fault detection by sending and receiving ETH-CC frames between MEPs periodically

Each MEP transmits ETH-CC frames periodically

If MEP does not receive any ETH-CC frames for 3.5 times of the ETH-CC frame

transmission interval, it provide alarm indication (loss of connectivity)

1 2 3 4

: MEP

: CCM

: CCM

Legend

Objectives

Operations

ETH-CC (Fault Detection)


To verify the connectivity between multiple equipments

Unicast ETH-LB ： verification between the designated 2 equipments

Multicast ETH-LB： verification the existence of the nodes in the same MEG

MEP#1 sends a Unicast ETH-LBM frame to MEP#4

MIP(#2,3) forwards the ETH-LBM frame to the far-end

MEP#4 terminates the ETH-LBM frame and reply a ETH-LBR frame

MEP#1 receive the ETH-LBR frame

1 2 3 4

:　MEP

:　MIP

:　LBM

:　LBR

Legend

ETH-LB (Fault Verification)

Objectives

Operations


To verify the route status and localization of the fault

MEP#1 sends a ETH-LTM frame to MEP#4

Each MIP (#2,#3) sends a reply ETH-LTR to MEP#1, and forwards the ETH-LTM frame with the decreased TTL value to the far-end

MEP#4 terminates the ETH-LTM frame and reply a ETH-LTR frame

MEP#1 receives the ETH-LTR frames which have the different TTL value.

ETH-LT (Fault Isolation)

Objectives

Operations

1 2 3 4

: MEP : MIP

Legend

: LTM

: LTR

TTL=n

TTL=n

TTL=n-1

TTL=n-1

TTL=n-2

TTL=n-2


iPASO200 Ethernet OAM functions

L2SW

iPASO200

MODEM

LAN

iPASOLINK200 supports only Down MEP/MIP

Ether OAM reply frame from Switch to LAN/MODEM port outward direction is okay

But from LAN/MODEM toward Switch directional is not supported


L2SW

iPASO200 #1

MODEM

LAN

L2SW

MODEM

LAN

Reply frame

NG

Reply frame OK

ETH-CC/LB/LT

Replay frame

NG

For this application, ETH-CC/LB/LT reply frame only at iPASO #1MODEM port

The MEP of IPASO #1should be set only at Modem port

iPASO200 #2

iPASO200 Ethernet OAM functions (2)


OAM Parameter Setting and Testing Example (1)

By external OAM Test Set

Left Access One MEP Index: 1

Right Access One MEP Index: 2

MEG ID: ABC (Domain Name)

MEG Level: 0

VLAN ID: 20

MEP 2

MEP 1

VLAN ID 20

Use Access One test set to perform OAM

Test

Check ETH CC ETH LB/LT results

Note: Create VLAN 20 before setup OAM

Access One

OAM Test Set

Access One

OAM Test Set

Set as MIP MIP

MIP

MIP MIP

MIP MIP MIP MIP


OAM Parameter Setting and Testing Example (2)

MEP Index: 1

MEG ID: ABC (Domain Name)

MEP ID: 1 at IDU1

MEP ID: 2 at IDU2

MEG Level: 0

VLAN ID: 20

Peer MEP ID: 2 at IDU1

VLAN ID 20

1

2

Note: Create VLAN 20 before setup

OAM

From left to right perform ETH LB/LT

control to check result

From right to left perform ETH LB/LT

control to check result

2 1

SW SW SW SW

2 1

Modem port

set as MEP1 Modem port

set as MEP2

MIP MIP MIP MIP


Problems of L2 Loop

(1)Storming:

Broadcast / Multicast Storm

DLF (Destination Lookup Failure)/Unknown Uni-cast Storm

(2)MAC Mis-Learning

Storm Frames rewrite MAC Table.

It caused flapping of Mac Learning Table.

MAC A

<MAC Table>

MAC A -- Port# 1

MAC A -- Port# 2

??


Blocking Port

Forwarding Port

Data Flow

Spanning Tree Protocol (STP)

Loop#1

Root Bridge

Disabled Redundant Path

Blocking Port

1- Root Bridge- one root bridge per network ( lowest BID)

2- One root Port per non root bridge. (port forwarding to root bridge)

3- Designated port per segment


STP Parameter Bridge ID

Bridge ID (STP, RSTP)

Bridge Priority Bridge MAC Address

Bridge ID (8 Bytes)

2bytes 6bytes

Default Bridge Priority = 32768 (IEEE 802.1d)

Bridge ID is main Parameter for Spanning Tree Algorithm,

The Bridge with lowest Bridge ID is selected to “Root Bridge”


STP Parameter - Path Cost

Path Cost is accumulated Cost between a Bridge to Root Bridge.

Root Bridge

100Base-Tx 1000Base-T

100Base-Tx

Link Speed Cost

10Gbps 2

1Gbps 4

100Mbps 19

10MBps 100

Path Cost defined in IEEE802.1d

0+4=4

4+19 =23

0+19 =19

19+100 =119

10Base-T *Port Cost is manually configurable


Bridge: A

Bridge ID 32768

MAC Address 00-00-00-00-00-01

Bridge: B

Bridge ID 32768

MAC Address 00-00-00-00-00-03

Bridge: C

Bridge ID 32768

MAC Address 00-00-00-00-00-02

Port 1

Port 2

Port 1 Port 2

Port 1

Port 2

Step 1:

All bridges will send

BPDU packets to each other to elect

who will be the Root bridge

How to decide:

Smallest ID win

Smallest MAC Address win

Step 2:

Result: Bridge A is the Root bridge

Bridge B, Bridge C are non Root

bridge

STP IEEE 802.1D - Theory background (1)

1- Root Bridge- one root bridge per network ( lowest BID)

2- One root Port per non root bridge. (port forwarding to root bridge)

3- Designated port per segment


Root Bridge

Bridge: A

Bridge ID 32768

MAC Address 00-00-00-00-00-01

Port 1 as

Root port

Non Root Bridge

Bridge: C

Bridge ID 32768

MAC Address 00-00-00-00-00-02

Port 1

Port 2

Port 2

Port 2

Step 3

Every non root bridge must select

one root port to send traffic to root

Bridge based on best root path cost

Suppose all connections are 100M

FE speed for this example

Non Root Bridge

Bridge: B

Bridge ID 32768

MAC Address 00-00-00-00-00-03

Port 1 as

Root port

RP

RP



Root Bridge

Bridge: A

Bridge ID 32768

MAC Address 00-00-00-00-00-01

Port 1 as

Root port

Non Root Bridge

Bridge: C

Bridge ID 32768

MAC Address 00-00-00-00-00-02

Port 1

Port 2

Port 2

Port 2

Step 4

Selections of Designated Ports

Port provided the least part cost

from the segment to the root

is elected as designated port

Result:

Since the ports on Bridge A are directly

connected to the root bridge, these ports

become the DP for S1 and S2

Port 1 of Bridge A as Designated port for

Segment 1

Port 2 of Bridge A as Designated port for

Segment 2

Non Root Bridge

Bridge: B

Bridge ID 32768

MAC Address 00-00-00-00-00-03

Port 1 as

Root port

RP

RP

Segment 3

Segment 1

Segment 2

DP

DP



Root Bridge

Bridge: A

Bridge ID 32768

MAC Address 00-00-00-00-00-01

Port 1 as

Root port

Non Root Bridge

Bridge: C

Bridge ID 32768

MAC Address 00-00-00-00-00-02

Port 1

Port 2

Port 2

Port 2

Continue on Step 5:

Election of Designated Ports

for segment 3

The path cost to the RB is the same for

Bridge B and Bridge C

The tie breaker is the lower MAC address of

bridge C

Result:

Port 2 of Bridge B as DP

Step 6:

RP and DP ports go into the forwarding states

Step 7:

Ports that are not DP or RP go to the blocking

state

Non Root Bridge

Bridge: B

Bridge ID 32768

MAC Address 00-00-00-00-00-03

Port 1 as

Root port

RP

RP

Segment 3

Segment 1

Segment 2

DP

DP


DP


Root Bridge

Bridge: A

Bridge ID 32768

MAC Address 00-00-00-00-00-01

Port 1 as

Root port

Non Root Bridge

Bridge: C

Bridge ID 32768

MAC Address 00-00-00-00-00-02

Port 1

Port 2

Port 2

Port 2

Step 8

At this point STP has

fully converged

Bridge C continuous to send

BPDU advertising its superiority

Over Bridge B

As long as this condition remain good

The port 2 of BR-B remain blocked

For any reason if Bridge B never

Receive BPDU for max. 20 sec

It will start to transition to forwarding

mode

Non Root Bridge

Bridge: B

Bridge ID 32768

MAC Address 00-00-00-00-00-03

Port 1 as

Root port

RP

RP

DP

DP


DP

Forwarding

Blocked

Forwarding

Forwarding

Forwarding

Forwarding

BPDU


Root Bridge

Bridge: A

Bridge ID 32768

MAC Address 00-00-00-00-00-01

Port 1 as

Root port

Non Root Bridge

Bridge: C

Bridge ID 32768

MAC Address 00-00-00-00-00-02

Port 1

Port 2

Port 2

Port 2

Spanning Tree Failure

The blocked port has gone into

Forwarding

Non Root Bridge

Bridge: B

Bridge ID 32768

MAC Address 00-00-00-00-00-03

Port 1 as

Root port

RP

RP

DP

DP


Forwarding

Was Blocked

Now forwarding

Forwarding

Forwarding

Forwarding

Summary of STP Port States

1. Blocking

2. Listening

3. Learning

4. Forwarding

5. Disabled

BPDU

DP


RSTP IEEE 802.1w - Theory background

RSTP vs STP

1. Ordinary STP takes 30 – 50 seconds to converge

2. Rapid Spanning Tree Protocol (RSTP) takes 1 to 2 seconds to converge

3. RSTP has two more port designations

4. In RSTP, all bridges send BPDU automatically

5. While in STP, only the root triggers BPDU

6. In RSTP, Bridges act to bring the networks to converge

7. While in STP, bridges passively wait for time-out before changing port states

RSTP is not so much a new protocol, but rather an improved and faster version of

STP, It preserves all the basic concepts of STP and interoperates with it as well.

iPASO200 only supported with port based RSTP


There are only three operational states assigned to each port by RSTP

RSTP splits the blocking port role into backup port and alternate port

RSTP IEEE 802.1W – vs STP IEEE 802.1D

Blocking Discarding NO NO

Listening Discarding NO NO

Learning Learning NO Yes

Forwarding Forwarding Yes Yes

Disabled Discarding NO NO

STP Port State RSTP Port State Is port included in

active Topology?

Is port Learning

MAC Address?

RSTP vs STP


How STP and RSTP works (1)?

2

2

1

1

1

111

222 333

444

1

2 2

B

Designated

Root Port

Blocked

FOR STP CASE

2

2

1

1

1

222

444

1

2 2

Switch 222 and 444 wait for 20 seconds for Max

Age Time

+ 15 seconds (listening)

+ 15 seconds ( learning)

Total 50 seconds to converge

111

333

B

R

D

D

D

D D

R

R R

R

R

R

D

D

D

iPASO200 Advanced Ethernet Functions

How STP and RSTP works (2)?

2

2

1

1

1

111

222 333

444

1

2 2

FOR RSTP CASE

2

2

1

1

1

222

444

1

2 2

When 222 loses it connection to 111, it immediately

Start it port 2 to inform 444, then 444 place it P2 to

Forwarding. 444 perform a hand shake with 222

Called “sync operation” The sync required a BPDU

Exchange, but does not use timers, and therefore

Perform fast switching!

111

333

B

Designated

Root Port

Blocked

R

D

B

D

D

D

D

R

R R

R

R

R

R

D

D

D


QoS Bit Assignment in the Packet

To MAC

Address

Fm MAC

Address

Type TCI Type IP Header IP data FCS

Version Header

Length

TOS IP address etc.

Priority

bit

CFI VLAN

ID

8bits

3bits

2Bytes

CFI: Canonical Format Indicator

FCS: Frame Check Sequence

TCI: Tag Control Information

TOS: Type Of Service

COS: Class Of Service

EXP : experimental bits ( iPASO200 will support in future)

MPLS

Label

MPLS

Label

IP Header IP data

Label Exp S TTL

3bits

1) IP Packet

2) MPLS Packet

VLAN Tag

(802.1q CoS)

ToS(3bit)

DSCP/Diffserve(6bit)

DSCP: Differentiated Services Code Point

IP ECN Explicit Congestion Notification

Release 1.30

IPASO200 supported

Either IP Precedence

Or DSCP at one equipment


Preamble

8byte

Destination

MAC address

(DA)

6byte

Source MAC

address

(SA)

6byte

VLAN

tag

4byte

Length

/ type

2byte

Data

46 - 1500byte

FCS

4byte

802.1q tag type

2byte

TCI field

2byte

Priority

3bit

CFI

1bit

VLAN-ID

12bit

Traffic management

Voice

Video

Control signal

Excellent effort

Best effort

Reserved

Background

7(high)

6

5

4

3

0

2

1 (low)

Example: traffic assignment

Classification traffic based on CoS value

Priority of traffic is decided by value of IEEE802.1p user priority field (CoS: Class of Service)

CoS value can be assigned 8 class from 0 to 7 to VLAN tag field

CoS value

CoS value

Classification –process of distinguishing one kind of traffic from another by examining the Layer

2 through Layer 3 and QoS fields in the packet


Policing Shaping

Policing

FE Port Modem Port Modem Port FE Port

Shaping

Ingress

Egress

Policing

Shaping Policing

Shaping

Summary of locations for Policing and Shaping

Default Setting Shaping: 4XSP

Default Setting of Policing : Nil


iPASOLINK QoS Mechanism

SP: Strict Priority, DWRR: Deficit Weighted Round Robin,

Classify for Egress

Queue with internal

priority

Token bucket

Token

Determine

equipment

internal priority

VLAN CoS

IPv4 precedence

IPv4/v6 DSCP

MPLS EXP

Ingress Policer

Class ４ queue

Class ３queue

Class ２ queue

Class １ queue

Egress Queue

Scheduling

and

Shaping

Sent

frames

iPASOLINK supports MEF/RFC4115 compatible policing: [Policing Entry] - per port / per port + CoS / per port + VLAN / per port + VLAN + CoS [Polcing Parameters] - CIR / EIR/ CBS/ EBS Committed Information Rate/ Excess Information Rate/Committed Burst Size/Excess Burst Size

Egress QoS function, previous stage of adaptive modulation supports per-class queuing with strict priority and deficit round robin mechanism. Each queue supports: - maximum rate shaping and minimum rate guarantee - weighted Tail drop (WTD) or weighted random early detection (WRED) congestion avoidance mechanism work with colors, colored by policing in the ingress stage. Also, per-port shaping is supported co-work each queue as hierarchical shaping

Two-Rate,

Three-Color Metering

TDM TDM

+ Packe

t

QoS Token bucket

Token


UNI

EVC1

EVC2

EVC3

Ingress Bandwidth Profile Per Ingress UNI

UNI

EVC1

EVC2

EVC3

Ingress Bandwidth Profile Per EVC1



UNI EVC1

CE-VLAN CoS 6 Ingress Bandwidth Profile Per CoS ID 6

CE-VLAN CoS 4

CE-VLAN CoS 2

Ingress Bandwidth Profile Per CoS ID 4

Ingress Bandwidth Profile Per CoS ID 2

EVC2

Port-based Port/VLAN-based

Port/VLAN/CoS-based

MEF 10.1 Traffic Management Model

EVC: Ethernet Virtual Connection


Summary of iPASO QoS Functions and Features

• iPASOLINK series supports fully functioned QoS control

• Supported classification methods: CoS/IP Precedence/DSCP EXP will be supported for MPLS

• Internal Classification: 8 classes (8 classes mapped to 4 classes for Egress Queue)

• Ingress policing: CIR, EIR (Two-Rate Three-Color Marking)

• Profile based QoS management is supported

• Scheduling: SP, SP+3DWRR, 4DWRR


Classification

VLAN CoS Internal

priority

7 7

6 6

5 5

4 4

3 3

2 2

1 1

0 0

IP

Precedence

Internal

priority

7 7

6 6

5 5

4 4

3 3

2 2

1 1

0 0

DSCP Internal

priority

63 7

: :

47 5

: :

31 3

: :

15 1

0 0

Classification profile is configurable.

Profile No.0 (ex) Profile No.1 (ex) Profile No.2 VLAN CoS

IPv4

precedence

IPv4/v6 DSCP

MPLS EXP

Determine equipment internal priority

Classification –process of

distinguishing one kind of

traffic from another by

examining the Layer 2

through Layer３ and QoS

fields in the packet


PIR

(CIR)

[Time]

[Am

ou

nt

of

Tra

ffic

]

Discard Markdown

Complying Frames

Violating Frames

Bandwidth Monitoring / Policing

(EIR)


What is CIR, EIR?

CIR Conformant

Traffic ≤ CIR

EIR Conformant

Traffic ≥ CIR

No traffic

Traffic ≥ PIR

CIR (Committed Information Rate) -

Minimum BW guaranteed for an Ethernet service.

Policing is enforcement of CIR

Zero CIR means Best effort (no BW is guaranteed)

EIR (Exceeded Information Rate) -

Service frames colored yellow may be

delivered but with no performance commitment.

PIR (Peak Information Rate) -

Maximum rate at which packets are allowed to be forwarded.

PIR = CIR + EIR (greater or equal to the CIR)

Service frames exceeding PIR are red packets and

are unconditionally dropped


Dual Token bucket (TRTCM)

Dual rate token bucket with a programmable CIR and EIR, as well as CBS and EBS. It also

named as Two rate ,Three-Colour Metering

Example: consider the extreme case

One bucket is used:

CIR=2Mbps, CBS=2KB, EIR=0,EBS=0

Case 1:

Two 1518 byte frames coming back to back

First frame take 2000-1518 token remain

482 byte, the second frame is immediately

Discarded

Case 2:

One frame 1518 is sent, 8 ms later, another

1518 byte arrive, since token bucket

Refill with CIR/8=250Kb/s

The token bucket is full again and able to

sent the second frame out with green

color.

CBS/EBS should be set depend on traffic

type

1. Bursty TCP-based traffic

2. UDP based type such as VoIP

Our Recommendations:

Note: Color Blind and Color Aware Rate Metering ( iPASO200 is color blind system)


Relationship among CIR, EIR,CBS,EBS

Important Parameter Setting for Policing

CIR: 0 to 1000000 kbps

EIR: 0 to 1000000 kbps

EBS: 0 to 128kbyte

CBS: 1 to 64 kbyte

Recommendation: EBS 48Kbyte, CBS: 24 KBytes

The EBS and the CBS are measured in bytes and both of them must be configured to be greater

than 0.

EBS is the maximum number of bytes allow for incoming packets to burst above the EIR but

still be marked yellow

CBS is the maximum number of bytes allow for incoming packets to burst above the CIR , but

still be marked green.

Note: Color Blind and Color Aware Rate Metering ( iPASO200 is color blind system)


Control the output sequence and bandwidth of frames from each queue according to

Output condition defined by Marker/Priority Determination.

Strict Priority Queuing (SPQ), Weighted Control (WRR) can be used as queuing method.

Round Robin (RR)

ETC Car

ETC Car

High Priority

Police Car

Elements of QoS - Scheduling /Queuing

ETC System

＝Electronic Toll Collection System


Determines whether the current frame to be queued or discarded, depending on the

packet priority and the state of the queue.

Not connected well…

Too Late!!

Little slow..

Comfortable!!

Average Utilization

Average Utilization

Traffic

Concentration

Window Size decrease globally

Ban

dw

idth

Time

Ban

dw

idth

Early detect and

restrain

Effective Window size variation

Elements of QoS ( Discard Control)

Time


Congestion Avoidance ( Discard Control)

iPASO200 support Weight Tail Drop at Release

1.07and later with WRED

Congestion avoidance techniques on the

egress queues.

Both techniques will drop packets when pre-

configured thresholds on the egress queues

have been reached.

Weighted Tail Drop (WTD), with thresholds

Setting on each queue, for congestion

avoidance

Threshold2

(75%)

Threshold1

(50%)

Threshold3

(100%)

Queuing Priority2: 0％ discard

Queuing Priority3: 0% discard


Queueing Priority1:100%discard



Queueing Priority1:100%discard




Egress Queue + Scheduling

SP

Class 3

WRR

Class 0 Divided throughput

by weighted condition

Class 3 absolute priority

Shaper Class 2

Class 1

Classify (Mapping) for Egress

Queue with internal priority Scheduling and Shaping

Mapping table is

Configurable.


Strict Priority mode

1. Operation of the output port shaper function

2. The total value 70 Mbps of class-3 to class-d will be shrank to 60 Mbps by the output shaper function

when it is output.

3. The total value 70 Mbps of output frames class-a to class-0 will be shrank by the output port shaper

function to 60 Mbps (class-3,-25 Mbps; class-2- 20 Mbps; class-1- 10 Mbps; class-0- 5 Mbps) in the

order of the priority from the lowest class to be output (when the frame length for the output bandwidth

for each input frame is 1500 bytes).

[Breakdown]

Class-3 25 Mbps

Class-2 20 Mbps

Class-1 10 Mbps

Class-0 5 Mbps

How it works?

iPASO200

Class-3

25 Mbps

Class-1

10 Mbps

Class-0

15 Mbps

Class-2

Class-1

Output port

shaper

function

Rate 60 Mbps

Class-2

20 Mbps

Rate 25 Mbps Class-3

Rate 20 Mbps

Rate 10 Mbps


Strict Priority Scheduling :The queue with the highest priority that contains

packets is always served (packet from that queue are de-queued and transmitted).

Packets within a lower priority queue will not transmit until all the higher-priority

queues become empty


Out port control -- SP + D-WRR mode

Frames of class-a is 42 Mbps decided in the SP (Strict Priority) mode will be output with the top priority.

1. The output port shaper function is 60 Mbps and the input rate of class-a is 42 Mbps, Deficit WRR surplus bandwidth

distribution function would be 60 Mbps − 42 Mbps = 18 Mbps

2. The weight of remaining three class is 3:2:1

1. Output rate of class-2: Surplus bandwidth 18 Mbps × Ratio 3 / (3+2+1) = 9 Mbps



How it works?

Cass-3

42 Mbps

Class-1

50 Mbps

Class-0

50 Mbps

class-1 DWRR

Output port

shaper

function


50 Mbps

iPASO200

Rate 42 Mbps class-3

SP (Strict Priority)

Rate 9 Mbps

Rate 6 Mbps

Rate 3 Mbps

[Breakdown]

class-3 42 Mbps

class-2 9 Mbps

class-1 6 Mbps

class-0 3 Mbps

class-2 DWRR

class-0 DWRR

Weighted Round Robin uses a number that indicates the importance (weight) of each queues.

WRR scheduling prevents the low-priority queues from being completely neglected during

periods of high-priority traffic. The WRR scheduler transmits some packets from each queue in

turn. The number of packets it transmits corresponds to the relative importance of the queue.


Delay and Buffer Size on Shaping

Principle: Maximum delay= Buffer size / Shaper rate

Ex.1) Buffer size 1Mbyte, Shaper rate 100Mbps

1M x 8(bit) / 100M(bit) = 0.08s

= 80ms

Ex.2) Buffer size 10Mbyte, Shaper rate 300Mbps

10M x 8(bit) / 300M(bit) = 0.2666s

= 266ms

Ex.3) Buffer size 128Kbyte, Shaper rate 155Mbps

128K x 8(bit) / 155M(bit) = 0.00645s

= 6.4ms

Delay specification based on application:

1) Voice: Less than several msec (North American discussion: One

Way:End-End 5msec)

2) Data: Several 10 msec to several 100 msec

Buffer size and the circuit position in Mobile Backhaul equipment 1) Access on Cell Site etc.: Several 100 Kbytes buffer size. 2) Aggregation Node: Several Mbytes to several 10 Mbytes buffer size. Large size buffer increases the delay. Equipment with small buffer memory is better for low latency.

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IPasolink 200 400 EthernetFeatures