TPS 서비스를 위한 Access 망의 QoS 기술 (42 pages)

QoS Technology in Access Network for TPS (Triple Play Service)

By Netmanias (tech@netmanias.com)

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Netmanias 기술문서: TPS 서비스를위한Access 망의QoS 기술

2006년5월23일
NMC Consulting Group(tech@netmanias.com)

2
Content
.IEEE 802.1 p/q, DiffServ
.영상전화서비스를위한동적Policy Provisioning (5-Tuple, PEP)
.영상전화서비스를위한Admission Control
.QoS 비지원DSLAM 접속가입자를위한Hierarchical Scheduling
.Case Study: KT, SBC

3
Ethernet CoS (IEEE 802.1p/q)
DMAC
SMAC
EType
Payload
FCS
6B
6B
2B
Up to 1500B
4B
DMAC
SMAC
EType
TPID
0x8100
TCI
Payload
FCS
6B
6B
Up to 1500B
4B
2B
2B
2B
802.1p
0
VLAN ID
3b
1b
12b
Ethernet Priority (CoS)3-bit value = 0 ~ 7represents up to 8 different classes0 = lowest class7 = highest class
VLAN ID
12-bit value, 1 ~ 4094
0 & 4095 are reserved (unusable)
TPID : Tag Protocol Identifier
TCI : Tag Control Information
VLAN ID : Virtual LAN Identifier
Untagged Ethernet Frame
VLAN tagged Ethernet Frame

4
IP DSCP
VER
IHL
DSCP
Total Length
Identification
0
Fragment Offset
TTL
Protocol ID
Header Checksum
SIP
DIP
IP option (if any)
IPv4 Header (variable size, up to 60B, default 20B)
6B
6B
EType
0x0800
2B
IP Header
CRC
4B
IP Datagram
0b
4b
8b
16b
19b
31b
DF
MF
20B~60B
20B
DMAC
SMAC
DSCP
=-64-bit value
=-able to represent many classes of services
Class Selector
bits
7
6
5
4
3
2
1
0
DSCP
CU
bits
7
6
5
4
3
2
IP
-
Prec
1
0
MBZ
TOS
D
T
R
C
IP Type Of Service (RFC 1349)
IP DiffServ Code Point (RFC 2474)
IPv4 Packet

5
DSCP Policy : Example
DSCP
CU
DSCP field
DROP Precedence
Class#1
Class #2
Class #3
Class #4
Low Drop Precedence
AF11
-1010
10
AF21
-10010
18
AF31
-11010
26
AF41
-100010
34
Medium Drop Precedence
AF12
-1100
12
AF22
-10100
20
AF32
-11100
28
AF42
-100100
36
High Drop Precedence
AF13
-1110
14
AF23
-10110
22
AF33
-11110
30
AF43
-100110
38
High Priority = EF = 101110 = 46(VoIP)Best Effort =  000000 = 0
.Class: Class Selector (CS) Code Points for backward compatibility with IP Precedence.(CS1: Priority, CS2: Immediate, CS3: Flash, CS4: Flash Override)
.Do not Use CS6 or CS7.
7
6
5
4
3
2
1
0

6
KT Access Network Architecture
전송망(SDH/DWDM)
Best-Effort IP Networks
Premium IP Networks
(MPLS)
C
C
E
E
R
R
R
R
SER
L2 SW
그림3
그림3
그림3
그림3
그림5 copy
그림4 copy
그림4 copy
그림4 copy
그림4 copy
L3 SW
그림5 copy
IP VDSL
L3
SW
CO
Apart
POP
GE
GE
FE
FE
그림4 copy
그림5 copy
그림5 copy
FE
GE
GE
그림5 copy
그림5 copy
50Mbps
Curb (캐비넷)
Apart
SER
Ethernet
VDSL
Ethernet
(Ntopia)
Ntopia
VSDL
(Apart)
FTTC+
VSDL
alpine3808
alpine3808
ATM ADSL
DSLAM
ont
IP ADSL2+
DSLAM
N
CO
POP
155Mbps
ONT
GE
GE
ont
image3225
OLT사진
8Mbps/4Mbps
(500Kbps)
CO
그림10 copy
IP ADSL
IP ADSL
(CO)
ADSL(CO)
FTTH
그림4 copy
alpine3808
BRAS
Apart
일반주택
VDSL
CO
FTTC+
Ethernet
(AON)
그림3
그림3
FE
일반주택
20/10Mbps
100Mbps
100Mbps
8Mbps
alpine3808
OLT사진
100M/.1
100M/.16
ONU
젂주
맨홀, 젂주
CO
onu
onu
100Mbps
Ethernet
FTTP
일반주택
F7024XG
그림10 copy
그림10 copy
WDM-PON
OLT
WDM-PON
OLT

7
KT End-to-end QoS
SER
ONT
Samsung%2520X100
Modem
Customer side
Wibro
FTTH
FTTP
Ntopia
IP xDSL
RAS
ACR
RN
FES+
그림3
RN
ONU
OLT
N-SW
L3 SW
L3 SW
그림4 copy
그림4 copy
Out side
BE IP Core
(KORNET)
Premium
IP core
(MPLS)
Network side
L3기반Marking and
Scheduling
L2기반Marking or BW provision
Scheduling,
Drop probabilty 적용
ㅇL3 Marking
or Remarking
ㅇPartly port based
Rate Limiting
ㅇScheduling
ㅇNtopia FES : 802.1p(2Queue)
ㅇ10M/20M DSLAM : 지원안함
ㅇ50M DSLAM : 802.1p
ㅇWibro : 차등화서비스(예정)
.IP QoS
ㅇScheduling
ㅇDrop probability
Scheduling,
Drop probabilty 적용
.MPLS QoS
ㅇExp bit기반QoS (E-LSP)
(scheduling, drop probability)
ㅇMPLS-TE
WDM-PON system
그림10 copy
alpine3808
DSLAM
그림5 copy

8
KT QoS Policy
Class
IP Prec/
EXP
Services
Queuing Policy

Gold
7
Reserved
-
6
Routing protocol packet패킷
BcN트래픽
PQ

Silver
5
Reserved
PQ가사용하고남은트래픽중50%
RED 사용
4
IP미디어Multicast 트래픽

Bronze
3
IP미디어Unicast 트래픽
PQ가사용하고남은트래픽중30%
RED 사용
2
VPN 가입자트래픽

Best-Effort
1
Reserved
PQ가사용하고남은트래픽중20%
RED 사용
0
기타트래픽

.KT Premium network QoS 기본정책: 4개의Class 운용

9
DiffServ : Admission Control
2Wire_HomePortal_1100_Residential_Gateway_Routers_and_Bridges-resized200
1107378_L1
IP Core
BRAS
IP DSLAM
그림15
그림2
그림4
IP-TV/VoD
Headend
Ethernet
Switch
Internet
100M
GE
xDSL
10 G
7450_blue
dslaccessnode1-s
SmartEdge_800_purple
10 G
10 G
10M
Aggregation
Speed Mismatch
10 G
10 G
10 G
GE
10M
.CAC를통해premium traffic flow 를사젂에제한하면best effort traffic의양과는상관없이premium traffic에대해서는QoS를보장해줄수있다.
.Premium Traffic이맋아지면Premium Traffic맊으로Congestion이발생할수있다.

10
Aggregation
SW
ER
ER
ER
ggsn-s
DSLAM/L2
Aggregation
SW
ggsn-s
DSLAM
KORNET
수원-공릉_Loss_edit
Network Data Loss (%)
boa
boa
Streaming Server
Network manager
2Mbps MPEG2 Streaming(UDP)
1G
100M
10M
1G
100M
10M
Video traffic
Data traffic
A Single FIFO
Current KT Network Test : End-to-end Packet Loss 측정Test (2005)

11
Data Plane : DiffServ 가지원되면…
Aggregation
SW
ER
ER
ER
ggsn-s
DSLAM
Aggregation
SW
ggsn-s
DSLAM
IP Core
수원-공릉_Loss_edit
Network Data Loss (%)
boa
Streaming
Server
Network manager
2Mbps MPEG2 Streaming
(UDP)
1G
100M
10M
1G
100M
10M
Video traffic
Data traffic
DiffServ queueing
No Loss & Only Propagation Delay
boa

12
Network manager
Aggregation
SW
ER
ER
DSLAM
IP Core
boa
Network manager
1G
100M
VoD
Streaming
Server
ggsn-s
boa
…
VoD User 2
VoD User 50
boa
VoD User 1
Network manager
…
2Mbps MPEG2 Streaming, each
Network manager
Aggregation
SW
ER
ER
ER
DSLAM
IP Core
boa
Network manager
1G
>100M
VoD
Streaming
Server
ggsn-s
Network manager
Network manager
…
VoD User 2
VoD User 50
VoD User 1
Network manager
…
2Mbps MPEG2 Streaming, each
boa
boa
boa
VoD User 51
boa
boa
Control Plane : Why Admission Control?

13
Why Dynamic QoS Provisioning ?
OSS
SER
200M
1G
1G
L2
L2
N
L3
10M/4M
20M/4M
SER
200M
1G
1G
#1
L2
L2
N
L3
20M/4M
10M/4M
#48
#24
P
I
Static Provisioning
(ACL(5-tuple, ..): Marking High, Limiting 1Mbps)
1)PC기반SoftPhone의경우, IP는동적유동IP이므로SoftPhone서비스가입(개통)시에가입자의IP를모른다.
2)가입자가DSLAM의어느DSL line에붙어있는지A-SW에게알려줄방법이없다.
3)수신자의IP (DstIP)를모르므로정책을할당할수없다.
4)QoS high 로마킹되어오는Upstream QoS attacks 을방지할수있는방법이없다.위와같은이유로Static Provisioning하는경우QoS attack을효과적으로방지할수있는방안이없다.
.PEP: A-SW
1107378_L1
videophone
1107378_L1
videophone
MF-Classifier
MF-Classifier
QoS Attack ??

14
KT Access Network Architecture
전송망(SDH/DWDM)
Best-Effort IP Networks
Premium IP Networks
(MPLS)
C
C
E
E
R
R
R
R
SER
L2 SW
그림3
그림3
그림3
그림3
그림5 copy
그림4 copy
그림4 copy
그림4 copy
그림4 copy
L3 SW
그림5 copy
IP VDSL
L3
SW
CO
Apart
POP
GE
GE
FE
FE
그림4 copy
그림5 copy
그림5 copy
FE
GE
GE
그림5 copy
그림5 copy
50Mbps
Curb (캐비넷)
Apart
SER
Ethernet
VDSL
Ethernet
(Ntopia)
Ntopia
VSDL
(Apart)
FTTC+
VSDL
alpine3808
alpine3808
ATM ADSL
DSLAM
ont
IP ADSL2+DSLAM
N
CO
POP
155Mbps
ONT
GE
GE
ont
image3225
OLT사진
8Mbps/4Mbps
(500Kbps)
CO
그림10 copy
IP ADSL
IP ADSL
(CO)
ADSL(CO)
FTTH
그림4 copy
alpine3808
BRAS
Apart
일반주택
VDSL
CO
FTTC+
Ethernet
(AON)
그림3
그림3
FE
일반주택
20/10Mbps
100Mbps
100Mbps
8Mbps
alpine3808
OLT사진
100M/.1
100M/.16
ONU
젂주
맨홀, 젂주
CO
onu
onu
100Mbps
Ethernet
FTTP
일반주택
F7024XG
그림10 copy
그림10 copy
Service Creation Layer
NMS & EMS
(Topology)
PS
SM
BB (CAC)
VoD
portal
IP-TV
portal
SIP
Proxy
Game
Application Layer
ASP
AAA
DHCP
WDM-PONOLT
WDM-PON
OLT

15
3 Layer Control Plane
A0028659_S
그림15
boa
videophone
그림11 copy
A0028659_S
videophone
Home
QoS
PEP(U)
PEP(D)
ip1
ip2
ip3
Service Creation Layer
NMS & EMS(Topology)
PS
SM
BB
AAA
DHCP
VoD
portal
IP-TV
portal
SIP
Proxy
Game
Application Layer
ASP
Service Request
Policy Provisioning
Admission control
A-SW
N-SW
SER
20M/4M
50M/8M
200M
1G
1G
RT
NRT
SP
200M
10M/4M
VoD
20M/4M
50M/8M
200M
1G
1G
200M
10M/4M
Call-level Dynamic Provisioning
인증시Provisioning
.
VP, SoftPhone
Internet
Multicast
VoD

16
SER
VoIP (SP/VP) Service flow (1) : L2 가QoS 제공하는경우
L3 SW/OLT
SER
KORNET
15. Policy Provisioning Request (DQP)
[OLT] srcIP=211.48.34.8, dstIP=220.20.10.5, Port#=2000: High
10. Policy Provisioning Request (DQP)
[OLT] srcIP=220.20.10.5, dstIP=211.48.34.8, Port#=2000: High
Application Layer
Service Creation Layer
PS
SM
BB
ASP
Call
Agent
PS
BB
PS
BB
Call
Agent
1. Call Setup Request
2. QoS Request (srcIP, dstIP, srcPort, dstPort,
Protocol-ID, 1Mbps, Service_ID=SP)
3
5
13
7
11
9
12
14
16
17. QoS RequestOK
18
19
4. Admission OK
6. Admission OK
8. Admission OK
220.20.10.5
Premium Core
(MPLS)
videophone
211.48.34.8
MF-Classifier
Network Layer
videophone
L3 SW/OLT
MF-Classifier
L2 SW/DSLAM
L2 SW/DSLAM

17
SER
VoIP (SP/VP) Service flow (1) : L2 가QoS 제공하는경우
L3 SW/OLT
SER
KORNET
Application Layer
Service Creation Layer
PS
SM
BB
ASP
Call
Agent
PS
BB
PS
BB
Call
Agent
9
6. Admission OK
8. Admission OK
220.20.10.5
Premium Core
(MPLS)
videophone
211.48.34.8
MF-Classifier
Reclassification!!
Network Layer
videophone
L3 SW/OLT
L2 SW/DSLAM
L2 SW/DSLAM
MF-Classifier
Reclassification!!
4. Admission OK
802.1p
DiffServ
DiffServ
over MPLS
DiffServ
DiffServ
802.1p
DiffServ

18
SER
VoIP (SP/VP) Service flow (1) : L2 가QoS 제공하는경우
L3 SW/OLT
SER
KORNET
15. Policy Provisioning Request (DQP)
[OLT] srcIP=211.48.34.8, dstIP=220.20.10.5, Port#=2000: High
10. Policy Provisioning Request (DQP)
[OLT] srcIP=220.20.10.5, dstIP=211.48.34.8, Port#=2000: High
Application Layer
Service Creation Layer
PS
SM
BB
ASP
Call
Agent
PS
BB
PS
BB
Call
Agent
1. Call Setup Request
2. QoS Request (srcIP, dstIP, srcPort, dstPort,
Protocol-ID, 1Mbps, Service_ID=SP)
3
5
13
7
11
9
12
14
16
17. QoS RequestOK
18
19
4. Admission OK
6. Admission OK
8. Admission OK
220.20.10.5
Premium Core
(MPLS)
videophone
211.48.34.8
MF-Classifier
Network Layer
videophone
L3 SW/OLT
MF-Classifier
L2 SW/DSLAM
L2 SW/DSLAM

19
VoIP (SP/VP) Service flow (2) : L2 가QoS 제공하지않는경우
Application Layer
Service Creation Layer
PS
SM
BB
ASP
Call
Agent
PS
BB
PS
BB
Call
Agent
9
6. Admission OK
8. Admission OK
4. Admission OK
SER
L3 SW/OLT
SER
KORNET
220.20.10.5
Premium Core
(MPLS)
videophone
211.48.34.8
Network Layer
videophone
L3 SW/OLT
L2 SW/DSLAM
L2 SW/DSLAM
MF-Classifier
Reclassification!!
DiffServ
DiffServ
over MPLS
DiffServ
DiffServ
DiffServ
MF-Classifier
Reclassification!!

20
VoIP Admission Control

21
KT 신인증(1)
SER
Access Network
Service Creation Layer
Network Layer
PS
SM
BB
NSP (Internet)
A10-NSP
N-SW
A-SW
DSLAM
U
Home
AAA
DHCP
1
그림5 copy
그림5 copy
그림5 copy
Control module
A-SW
N-SW
1. DHCP Discover(m1)
11. DHCP ACK
(m1, 211.48.34.8 )
DHCP Relay
Option 82
3. MAC Auth.
Request (m1)
5. Redirect Policy
3
5
6. DHCP Discover
(m1, A-SW 101, Port1)
7. DHCP ACK
(m1, 211.48.34.8)
8. Report (211.48.34.8: A-SW 101, Port1)
Web portal
4. LDAP (m1)
Application Layer
A0028659_S
videophone
211.48.34.8
9. Report (m1, 211.48.34.8)
10. Report
Subscriber_ID
SSR
Circuit_ID
MAC
IP
ID
PW
Service
Status

SI 1
m1
211.48.34.8

4
4
10

Subscriber DB server
2. DHCP discover (Agent Circuit ID= A-SW port 1)
24
D
101

22
KT 신인증(2)
SER
Access Network
Service Creation Layer
Network Layer
PS
SM
BB
NSP (Internet)
A10-NSP
N-SW
A-SW
DSLAM
Home
AAA
DHCP
그림5 copy
그림5 copy
그림5 copy
Control modle
A SW
D
N-SW
13. 인증창
19. Policy Provisioning .srIIP=211.48.34.8: Open gate, T-C, C-I
.dstIP=211.48.34.8: BoD (SSR=10Mbps)
Web
portal
Application Layer
A0028659_S
videophone
211.48.34.8
18. Report
Subscriber_ID
SSR
Circuit_ID
MAC
IP
ID
PW
Service
Status

netmanias01
10M
SI 1
m1
211.48.34.8
netmanias
1234
1 (Internet, 10M)

18
18
4
4
10
18
18
18

Subscriber DB server
12. www.netmanias.com
14. ID/PW=netmanias/1234
15
16. IP/PW (netmanias/1234)
17. Service
Redirect

23
After Authentication
Subscriber_ID
SSR
Circuit_ID
MAC
IP
ID
PW
Service
Status

netmanias01
10M
SI 1
m1
211.48.34.8
netmanias
1234
1 (Internet, 10M)

srcIP
Policy

211.48.34.8
Pass

18. PS (Subscriber DB)의가입자서비스묶음표
19. SER ACL (인증후)
8. BB Topology Map
211.48.34.8
100M
1G
1G
1
Pre-configuration (manual)
101
102
1001
104
103
SrcIP
USER_ID
DSLAM ID
A-SW ID
SER_Port

211.48.34.8
Netmanias
1001
101
210.123.32.7-3/2

7. DHCP Server의IP Lease Table
BB는211.48.34.8이A-SW 101의첫번째Port, 즉DSALM 1001에붙어있는것을인증과정에서안다.
(A-SW가DHCP Relay할때Option 82하고DHCP 서버가211.48.34.9을할당한후이를BB에게알려줘서안다.)
단, BB는211.48.34.8이DSLAM 1001에연결되어있다는것은알지맊DSLAM의어느Port에접속되어있다는것은모른다.
DSLAM
A-SW
N-SW
SER

24
신인증절차(1) : Explicit
SER
Policy Server
AAA server
Services
Subscriber
L3 SW
DHCP Relay
DHCP Discovery
MAC auth request (MAC=m3)
MAC auth response (Redirect policy)
MAC=m3
DHCP request (m3)
DHCP ack (m3, ip3)
DHCP Proxy
Report (m3, ip3)
DHCP ack (m3, ip3)
DHCP ack (m3, ip3)
DHCP Discovery
MAC=m3
IP=ip3
HTTP Redirect
www…..
인증창
Web Portal
id3/pw3
Authentication request (id3/pw3)
Radius Proxy/DB
Radius Client
Radius Server
Web portal
Authentication response (Service)
SNMP set (Service)
Accounting request (start)
Accounting request (start)
Accounting response
Accounting response
SNMP response
Services
Service (Internet,…)
DHCP server
DHCP server
Booting
ip3: Redirect
ip3: Service
1. PC와같이ID/PW 를Web 창에서입력할수없는단말인경우

25
SER
Policy Server
AAA server
Services
Subscriber
L3 SW
DHCP Relay
DHCP Discovery
MAC auth request (MAC=m3)
MAC auth response (Service)
MAC=m3
DHCP request (m3)
DHCP ack (m3, ip3)
DHCP Proxy
Report (m3, ip3)
DHCP ack (m3, ip3)
DHCP ack (m3, ip3)
DHCP Discovery
MAC=m3
IP=ip3
Web Portal
Authentication request (id3/pw3)
Radius Proxy
DB(m3:id3, pw3)
Radius Client
Radius Server
Authentication response (Service)
Services
DHCP server
DHCP server
Booting
ip3: Service
Service (Internet,…)
MAC정보-ID/PW변홖
1. PC에서인증을한번받은후에Reboot 하는경우
2. STB, SIP phone 등ID/PW 를Web 창에서입력할수없는단말인경우
신인증절차(2) : Implicit .PS가Device MAC을ID/PW로변환하여인증대행

26
211.48.34.8
100M
1G
0.1
Pre-configuration (manual)
1
104
103
L2
OLT (L3)
N-SW
SER/MGW
DSLAM
A-SW
100M
1G
1G
210.10.10.20
.Admission Control
.가입자인증시에Topology Map 에가입자IP를매달아두고, VoIP 서비스를요청하면Admission Control을수행함
.Access BB Topology Map
100M
Topology Map for Admission Control

27
1. Discovery L3 topology (Passive routing protocol).L3 topology discovery and traffic route 정보를동적으로수행해야한다.
.BB domain 내에서사용되는라우팅프로토콜에passive 하게참여한다. (OSPF, IS-IS, BGP)
.L3 topology, route table에변화가발생한것을즉시알아야한다.2. Discovery Link BW (SNMP)
.Link BW, Link Up/Down 정보를동적으로알아야한다.
.BB domain 안에있는모든L2, L3 장비에게SNMP GET 메시지를사용하여동적으로정보를수집
.Link Up/Down 발생시, L2, L3 장비에서BB에게SNMP Trap 메시지를젂송할수있어야한다.3. Link-by-Link 에서할당가능한max VoIP traffic BW는운영자가설정가능해야한다(Traffic 사용량에따라통계적으로변경가능해야….)
.VoIP 서비스제공을위한Effective Bandwidth, Call Blocking Ratio, Erlang등의계산결과를반영Ex) Max VoIP Link BW = [N by Erlang’SB formula] x [Effective Bandwidth(Markov Model)]
Topology Discovery and Resource Management

28
A-SW
N-SW
SER/
MGW
videophone
HOME
CO
POP
WDM-PON system
그림10 copy
Premium Core(MPLS)
VoIP
HOME
WDM-PON system
HOME
1G
1G
1G
VoD
alpine3808
VoIP
VoIP
Effective Bandwidth = 46kbps (G.711 64kbps 에대해서)
Call Blocking Ratio = 0.1%, Call arrival rate = 1call/2hours
Mean service time = 3min, VoIP User = 10,000
N by Erlang’sB Formula =  273
VoIP Bandwidth = 46kbps x 291 = 13.386Mbps  << 1Gbps
Acceesnetwork 에서Diffserv를지원하고, VoIP 트래픽에EF (Expedited Forwarding) class 를할당하면Admission Control은왜필요하지??
VoIP User = 10,000/4= 2,500  (집선비4 : 1)
N by Erlang’sB Formula =  77
VoIP Bandwidth = 46kbps x 86 = 3.956Mbps    << 1Gbps
그림3
그림3
L2 SW/DSLAM
L2 SW/DSLAM
videophone
Kornet
VoIP CAC : Access network

29
WDM
OLT
N-SW
SER/
MGW
ONT
/RG
(L2+)
A0028659_S
videophone
HOME
100M/.1
100M/.32
CO
POP
WDM-PON system
그림10 copy
BcN Core
(MPLS)
KORNET
VoIP
HOME
100M/.32
WDM-PON system
ONT
/RG
(L2+)
A0028659_S
videophone
HOME
100M/.1
100M/.32
100M/.32
1G
1G
1G
IP-TV
VoD
alpine3808
VoIP
VoIP
Effective Bandwidth = 46kbps + 1Mbps
Call Blocking Ratio = 0.1%, Call arrival rate = 1call/2hours
Mean service time = 3min, VoIP User = 10,000
N by Erlang’s B Formula = 273
VoIP Bandwidth = 1.046Mbps x 273 = 285.558Mbps  < 1Gbps
VoIP User = 10,000/4= 2,500  (집선비4 : 1)
N by Erlang’sB Formula =77
VoIP Bandwidth = 1.046Mbps x 77 = 80.542Mbps  < 1Gbps
그럼영상젂화에서는???
Assumption)
-Video : 1Mbps CBR
-Voice : 64kbps CBR (On-Off Model)
VoIP CAC : Access network

30
.Only Voice Service
.Voice Codec: G.711(64kbps) 기준
.KT Access Network 에서VoIP  Admission Control 수행은필요없을것으로판단됨.
.앞의예제에서VoIP BW 는Link Bandwidth 0.13 %맊을요구함
.영상젂화
.Video: 1Mbps CBR, Voice: 64kbps CBR (On-off Model)
.N-SW .SER 갂Link Bandwidth 의약28.5 % 를영상젂화용으로점유함.
.A-SW .N-SW 갂Link Bandwidth의약8%를영상젂화용용으로점유함
.이경우고품질VP 서비스를위한대역폭(285.558Mbps)을제외한대역폭을VoD, IP-TV, Internet 서비스용으로사용해야함.
.Ex) VoD, IP-TV, Internet Bandwidth = 1Gbps .285.558Mbps = 714.442Mbps
.VoD, IP-TV, Internet 서비스등도동시에제공해야하므로BB는VP Traffic 요구가285.558Mbps 이상이되면호수락을거부
Discussion

31
OLT
SER
A-SW/OLT
SER
A-SW/OLT
SER
KORNET
100M/.10
220.20.10.5
211.48.34.8
100M/.10
100M/.10
100M/.10
MF-Classifier
Reclassification !!!
Marking
MF-Classifier
Reclassification !!!
Marking
DiffServ
DiffServ over MPLS (E-LSP)
DiffServ
802.1p
0.1
0.1
Premium Core
DiffServ
N-SW
DiffServ
DiffServ
DiffServ
DSCP-to-EXP mapping
DSCP-to-EXP mapping
N-SW
videophone
videophone
LSP BW = 200Mbps
Effective Bandwidth = 46kbps
Call Blocking Ratio = 0.1%, Call arrival rate = 1call/2hours
Mean service time = 3min, VoIP User = 50,000
N by Erlang’sB Formula =  1,329
VoIP Bandwidth = 46kbps x 1,329 = 119.783Mbps
이때BB 는VoIP Traffic으로할당되는BW >  119.783 Mbps 인경우는호수락을
거부하여, 다른응용서비스제공을위한BW를확보하도록한다.
Assumption)
#NAME?
-E-LSP Bandwidth = 200Mbps
-Voice : 64kbps CBR (On-Off Model)
L2/DSLAM
L2/DSLAM
802.1p
VoIP CAC : Premium Core

32
LSP BW = 200Mbps
Effective Bandwidth = 46kbps + 1Mbps
Call Blocking Ratio = 0.1%, Call arrival rate = 1call/2hours
Mean service time = 3min, VoIP User = 50,000
N by Erlang’sB Formula =  1,329
VoIP Bandwidth = 1.046Mbps x 1,329 = 1390.134Mbps
.LSP BW 를증설해야한다
그럼영상젂화에서는???
Assumption)
#NAME?
-E-LSP Bandwidth = 200Mbps
-Video : 1Mbps CBR
-Voice : 64kbps CBR (On-Off Model)
OLT
SER
A-SW/OLT
SER
A-SW/OLT
SER
KORNET
100M/.10
220.20.10.5
211.48.34.8
100M/.10
100M/.10
100M/.10
MF-Classifier
Reclassification !!!
Marking
MF-Classifier
Reclassification !!!
DiffServ
DiffServ over MPLS (E-LSP)
DiffServ
802.1p
0.1
0.1
Premium Core
DiffServ
N-SW
DiffServ
DiffServ
DiffServ
DSCP-to-EXP mapping
DSCP-to-EXP mapping
N-SW
videophone
videophone
L2/DSLAM
L2/DSLAM
802.1p
Marking
VoIP CAC : Premium Core

33
Hierarchical Scheduling in SER
(Non-QoS DSLAM/L2 SW)

34
Network Layer : No QoS DSLAM
A0028659_S
그림15
boa
videophone
그림11 copy
A0028659_S
videophone
HOME
20M/4M
50M/8M
200M
1G
1G
ip1
RT
ip3
NRT
SP
DSLAM
A-SW
5124/5124F/4124
N-SW
200M
10M/4M
VoD
SER
PEP(U)
PEP(D)
20M/4M
50M/8M
200M
1G
1G
200M
10M/4M
DiffServ
DiffServ
DRP (IP-TV, VoD, VP, SP), IP-based queueing, shaping, RT/NRT scheduling
DiffServ
BE
DiffServ (MF-PC & making)
Marking (DQP): VP, SoftPhone
BE
DiffServ (BA-PC)
QoS
Downstream
Upstream
No QoS DSLAM/L2 SW

35
Downstream QoS
SER
ASP (IP-TV)
NSP (Internet)
Contents
N-SW
Agg-SW
DSLAM
DSLAM 101
Line 1
그림5 copy
그림5 copy
그림5 copy
RT
NRT
SP
ASP (VoD)
Contents
ASP (VP, SP)
A0028659_S
그림15
boa
videophone
그림11 copy
A0028659_S
videophone
HOME
Multicast
.근본적인문제: 10M/20M DSLAM이BE 장비임. SER과N-SW, A-SW에서DiffServ를지원해도DSLAM의VDSL Line에서Congestion발생함. (M&S Problem)
.SER에서SI interface를SSR로Shaping하고Premium Service에높은우선순위를주자. (SI Shaping + IP DiffServ)
.불행히도,
1)현재SER은한가입자의서로다른응용서비스가단말의IP 주소가다른경우하나의SI맊을통해처리되지못함.따라서PC와다른IP 주소를갖는VP의경우별도의RT queue를통해서비스된다.
2)IP-TV의경우SER에서Multicast traffic은가입자별로구분되어큐잉되지않으므로SER의SI Interface를통과하지않는다.
3)VoD의경우N-SW를통해액세스망으로유입되므로SER을통과하지않는다.
.따라서, SER내부로직맊으로는가입자단위로Shaping할수가없다.
.대책: PS가가입자서비스묶음표를관리하여Service request시에DRP (Dynamic Rate Provisioning)를해주어야한다.
10Mbps
Diffserv
Diffserv
IP-Based queueing
BE

36
SER DRQ (Dynamic Rate Provisioning)
SER
N-SW
Agg-SW
DSLAM
그림5 copy
그림5 copy
그림5 copy
RT
NRT
SP
Control module
.VideoPhone, SoftPhone트래픽은RT Queue를할당하고Internet traffic은NRT queue를할당하는방안임.
.RT queue에대해서는항상QoS 보장이가능하나한가입자의복수단말로젂달되는Traffic을하나의SI로정의하여Shaping하지못한다. (SER에서Home-Grouping이안되는문제)
.이로인해VideoPhone서비스이용시에PS가해당하는가입자로가는Internet traffic에대해서SER에DRP (Dynamic Rate Provisioning)을수행해야한다.
.IP-TV traffic은Multicast Queue로처리됨.
.VoD는NTOPIA SW에서유입되므로SER의Queue를통과하지않음.
VP(210.10.10.25) , SoftPhone (211.48.34.8)
Internet (211.48.34.8)
Multicast
A0028659_S
그림15
boa
videophone
그림11 copy
A0028659_S
videophone
HOME
210.10.10.25
211.48.34.8
210.20.1.17
VoD

37
Upstream QoS
Policy Server
SER
Premium
Core
Kornet
#1
#48
10M/4Mbps
20M/4Mbps
50M/8Mbps
#1
#48
200Mbps
1Gbps
1Gbps
#1
UDP: High & Rate-limiting 3/4Mbps
TCP: Low
* 3M: 144M,  4M: 192M
srcIP
dstIP
Port#
Policy

221.145.24.80
Called IP
2000(VP)
Marking High

else
Else
Marking Low

221.145.24.81
any
any
Marking Low

영상젂화이용시
Over-Provisioning
High
Low
High
Low
Rate-limiter
TCP
UDP
TCP
UDP
videophone
1107378_L1
smb600
PEP(U/D)
Subscriber stateless
Subscriber stateless
DQP
DQP: Dynamic QoS Provisioning
221.145.24.80
221.145.24.81

38
Upstream QoS
.KT DSLAM QoS 현황
.KT에기도입된대부분의10M/20M VDSL DSLAM은QoS 기능(MF-Classification, BA-Classification, Marking, Priority Queueing)을지원하지않는다.
.2004년부터도입된50M VDSL DSLAM은위의QoS 기능을지원한다.
.DSLAM에서QoS 저하를어떻게막을것인가?
1) 10M/20M DSLAM:
.10M/20M DSLAM(BE), A-SW(MF-Classification & Marking), N-SW (DiffServ), SER (DiffServ)
.10M/20M VDSL Service는Upstream rate을젂송계층에서4Mbps로제한시켜놓았고DSLAM과A-SW갂의Link capacity를200M로증설하면DSLAM의Uplink는Over-provisioning되어Congestion이발생하지않는다. (4*48=192M < 200M)
2) 50M DSLAM, FES+
.50M DSLAM, FES+ (TCP=LOW, UDP=HIGH & rate limiting 4Mbps), A-SW (MF-Classification & Marking), N-SW (DiffServ), SER (DiffServ)
.50M VDSL service의Upstream rate은현재8Mbps이므로Over-Provisioning으로문제를풀수없다. (8*48=384M>200M).  이경우DSLAM은Packet Classification을통해TCP는LOW로처리하고UDP는HIGH (영상젂화는UDP이므로)로처리한다.  이때QoS Attack이있을수있으므로각가입자별UDP traffic을4Mbps로Rate-limiting시킨다.

39
KT Phase 1 : MMoIP
SER
N-SW
DSLAM
4xG
12xG
100M/
200M
L3 SW
그림5 copy
그림5 copy
1G
Shared IP Access Network
PE
PE
PE
PE
PE
PE
GW Router
Premium
IP core
(IP/MPLS)
PE
BE IP Core
(KORNET)
4xG
4xG
GSR
그림4 copy
그림4 copy
그림4 copy
혜화
구로
10G
10G
10G
L2SW
Encoder
그림9
그림9
ICM
ICM
L4SW
Servers
IP-TV Headend(혜화)
RP
RP
Anycast RP
H.264
SD: 2Mbps
HD: 6~8Mbps
VoD
Public Internet
KIX
KT IDC
KT IDC
gx250
alpine3808
IMS
SER
N-SW
DSLAM
4xG
12xG
100M/
200M
L3 SW
그림5 copy
그림5 copy
1107378_L1
videophone
2Wire_HomePortal_1100_Residential_Gateway_Routers_and_Bridges-resized200
그림11 copy
그림15
boa
그림5 copy
1G
HOME
RG
Shared IP Access Network
4xG
4xG
그림4 copy
그림4 copy
그림4 copy
MMoIP
STB
PC
VoD
gx250
alpine3808
IMS
그림10 copy
그림10 copy
DSLAM (L2+)이source IP를보고marking
(Premium IP=High, Kornet IP=Low)
PBR (srcIP)
.Premium 단말(STB)는Premium IP address를DHCP로할당받음
.PC는KornetIP address를DHCP로할당받음.
.미리Premium 단말의MAC을DHCP server에설정
.Traffic 분리: N-SW에서PBR (srcIP기반)
1107378_L1
videophone
2Wire_HomePortal_1100_Residential_Gateway_Routers_and_Bridges-resized200
그림11 copy
그림15
boa
HOME
RG
MMoIP
STB
PC
1107378_L1
videophone
2Wire_HomePortal_1100_Residential_Gateway_Routers_and_Bridges-resized200
그림11 copy
그림15
boa
RG
MMoIP
STB
PC
2Wire_HomePortal_1100_Residential_Gateway_Routers_and_Bridges-resized200
Modem
PC
1107378_L1
그림5 copy
High
Low

40
Phase 2 : MMoIP
alpine3808
BRAS (SER)
N-SW
DSLAM
4xG
12xG
100M/200M
L3 SW
그림5 copy
그림5 copy
1107378_L1
videophone
2Wire_HomePortal_1100_Residential_Gateway_Routers_and_Bridges-resized200
그림11 copy
그림15
boa
그림5 copy
1G
HOME
RG
Shared IP Access Network
PE
PE
PE
PE
PE
PE
GW Router
Premium IP core
(IP/MPLS)
PE
BE IP Core
(KORNET)
4xG
4xG
GSR
그림4 copy
그림4 copy
그림4 copy
혜화
구로
10G
10G
MMoIP
그림10 copy
alpine3808
BRAS (SER)
N-SW
VDSL(L2)
4xG
12xG
100M/
200M
L3 SW
그림5 copy
그림5 copy
1107378_L1
videophone
2Wire_HomePortal_1100_Residential_Gateway_Routers_and_Bridges-resized200
그림11 copy
그림15
boa
그림5 copy
1G
HOME
RG
Shared IP Access Network
4xG
그림4 copy
그림4 copy
그림4 copy
MMoIP
그림10 copy
10G
Octave Switch (SSW)
QoS Manager (Global Coordination)
Access QoS Manager
Core QoS Manager
Access QoS Manager
5-tuple, service policy
CAC (Up)
5-tuple, service policy
CAC (Up)
CAC
PEP
PEP
CAC (Down)
CAC (down)
ESCP
CS
AC
CS
AC
Service Request

41
DSLAM
(FTTN)
SAIC
L2 SW (BSA)
CO
Internet
BRAS
(Edge Router화)
National Video Content Distribution Network
(IP Multicast)
PEP
7330
7450 ESS
7750 SR
SmartEdge_800_purple
GE
2Wire_HomePortal_1100_Residential_Gateway_Routers_and_Bridges-resized200
RG(L3)
STB
PC
GE
7750_red_sr12
7750_red_sr12
7750_red_sr12
7750_red_sr12
BSR
BSR
AAA
Server
IP-TV
VoIP
Internet
Home 1001
IP-TV
VoD
SSW
videophone
POTS
1107378_L1
그림11 copy
그림15
boa
DHCP snoop/relay
(Option82: VLAN ID)
DHCP proxy
DHCP discover (Option 60/61 = VoIP?)
DHCP offer
DHCP request
DHCP ack (10.20.192.10 for VoIP?)
STB (DHCP Client)
DHCP
PC (DHCP Client)
DHCP
DHCP Client
DHCP
Server
-5750
RB SMS1800
5750 SSC (Bridgewater)
Dynamic Policy Configuration
(= KT 신인증and
DQP=5-Tuple/TuboButton)
DHCP/
option82
BSA1/VLAN 1001: 10.20.192.10
DHCP
Server
RADIUS
Server
Accounting
Per-subscriber, per-service accounting queueing and policing/shaping/filtering
VLAN
1001
VLAN1400
Per-subscriber HIS shaping (PIR/CIR)
PDP
2Wire_HomePortal_1100_Residential_Gateway_Routers_and_Bridges-resized200
RG(L3)
STB
PC
Home 1400
videophone
POTS
1107378_L1
그림11 copy
그림15
boa
dslaccessnode1-s
VLAN 1400
VLAN 1001
7750_red_sr12
Voice VLAN
Video VLAN
Internet VLAN
Install Static ARP cache entry in BSR (user MAC/user IP)
(SecureARP)
Install anti-spoof rule per user
(IP Lease Table)
L3
(BSR)
SBC Phase 2: Dynamic Policy Configuration

42
End of Document