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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
2 iPASO200 Advanced Ethernet Functions © NEC Corporation 2010 Page 2
VLAN10 VLAN20
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
3 iPASO200 Advanced Ethernet Functions
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
4 iPASO200 Advanced Ethernet Functions © NEC Corporation 2010 Page 4
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
5 iPASO200 Advanced Ethernet Functions © NEC Corporation 2010 Page 5
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)
6 iPASO200 Advanced Ethernet Functions
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
7 iPASO200 Advanced Ethernet Functions
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
8 iPASO200 Advanced Ethernet Functions
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
9 iPASO200 Advanced Ethernet Functions
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?
10 iPASO200 Advanced Ethernet Functions
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
11 iPASO200 Advanced Ethernet Functions
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
12 iPASO200 Advanced Ethernet Functions
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
14 iPASO200 Advanced Ethernet Functions © NEC Corporation 2010
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)
15 iPASO200 Advanced Ethernet Functions © NEC Corporation 2010
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
16 iPASO200 Advanced Ethernet Functions © NEC Corporation 2010
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
17 iPASO200 Advanced Ethernet Functions
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
18 iPASO200 Advanced Ethernet Functions
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)
19 iPASO200 Advanced Ethernet Functions
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
20 iPASO200 Advanced Ethernet Functions
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
21 iPASO200 Advanced Ethernet Functions
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
??
22 iPASO200 Advanced Ethernet Functions
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
23 iPASO200 Advanced Ethernet Functions
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”
24 iPASO200 Advanced Ethernet Functions
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
25 iPASO200 Advanced Ethernet Functions
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
26 iPASO200 Advanced Ethernet Functions
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
STP IEEE 802.1D - Theory background (2)
27 iPASO200 Advanced Ethernet Functions
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
STP IEEE 802.1D - Theory background (3)
28 iPASO200 Advanced Ethernet Functions
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
STP IEEE 802.1D - Theory background (4)
DP
29 iPASO200 Advanced Ethernet Functions
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
STP IEEE 802.1D - Theory background (5)
DP
Forwarding
Blocked
Forwarding
Forwarding
Forwarding
Forwarding
BPDU
30 iPASO200 Advanced Ethernet Functions
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
STP IEEE 802.1D - Theory background (6)
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
31 iPASO200 Advanced Ethernet Functions
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
32 iPASO200 Advanced Ethernet Functions
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
33 iPASO200 Advanced Ethernet Functions
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
35 iPASO200 Advanced Ethernet Functions
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
36 iPASO200 Advanced Ethernet Functions © NEC Corporation 2010
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
37 iPASO200 Advanced Ethernet Functions
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
38 iPASO200 Advanced Ethernet Functions
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
39 iPASO200 Advanced Ethernet Functions
UNI
EVC1
EVC2
EVC3
Ingress Bandwidth Profile Per Ingress UNI
UNI
EVC1
EVC2
EVC3
Ingress Bandwidth Profile Per EVC1
Ingress Bandwidth Profile Per EVC2
Ingress Bandwidth Profile Per EVC3
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
40 iPASO200 Advanced Ethernet Functions
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
41 iPASO200 Advanced Ethernet Functions
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
42 iPASO200 Advanced Ethernet Functions
PIR
(CIR)
[Time]
[Am
ou
nt
of
Tra
ffic
]
Discard Markdown
Complying Frames
Violating Frames
Bandwidth Monitoring / Policing
(EIR)
43 iPASO200 Advanced Ethernet Functions
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
44 iPASO200 Advanced Ethernet Functions
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)
45 iPASO200 Advanced Ethernet Functions
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)
46 iPASO200 Advanced Ethernet Functions
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
47 iPASO200 Advanced Ethernet Functions
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
48 iPASO200 Advanced Ethernet Functions
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
Queuing Priority1: 0% discard
Queueing Priority1:100%discard
Queuing Priority2: 0% discard
Queuing Priority3: 0% discard
Queueing Priority1:100%discard
Queuing Priority2: 100% discard
Queuing Priority3: 0% discard
49 iPASO200 Advanced Ethernet Functions
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.
50 iPASO200 Advanced Ethernet Functions
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
Rate 15 Mbps Class-0
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
51 iPASO200 Advanced Ethernet Functions
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
2. Output rate of class-1: Surplus bandwidth 18 Mbps × Ratio 2 / (3+2+1) = 6 Mbps
3. Output rate of class-0: Surplus bandwidth 18 Mbps × Ratio 1 / (3+2+1) = 3 Mbps
How it works?
Cass-3
42 Mbps
Class-1
50 Mbps
Class-0
50 Mbps
class-1 DWRR
Output port
shaper
function
Rate 60 Mbps Class-2
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.
52 iPASO200 Advanced Ethernet Functions
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.