DiffServ-aware-MPLS Networking - APNOMS

DiffServ-aware-MPLS DiffServ-aware-MPLS Networking: Networking: aa Promising Promising Traffic Traffic Engineering Engineering for for Next Next Generation Generation Internet Internet (NGI) (NGI) 2002. 9. 25.

Youngtak Kim Advanced Networking Technology Lab. (ANT Lab.) Dept. of Information & Communication Engineering, YeungNam University, Korea ([email protected]) APNOMS2002 Tutorial, Young-Tak Kim, Advanced Networking Technology Lab. (ANT Lab.), YeungNam Univ.

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Outline ? Networking Model and Traffic Engineering of NGI ? Differentiated Service (DiffServ) ? MPLS (Multi-protocol Label Switching) ? Traffic Engineering with DiffServ-over-MPLS ? Internet Traffic Engineering Measurement, Performance Monitoring ? MPLS Fault Restoration ? DiffServ-aware-MPLS TE of Commercial Routers ? Summary and Discussions

APNOMS2002 Tutorial, Young-Tak Kim, Advanced Networking Technology Lab. (ANT Lab.), YeungNam Univ.

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Networking Model and Traffic Engineering of Next Generation Internet (NGI)


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Required Features of Next Generation Internet ? Guaranteed Bandwidth & QoS ? Bandwidth: ?peak information rate (PIR), committed information rate (CIR), minimum information rate ? Peak Burst Size (PBS), Committed Burst Size (CBS), Excess Burst Size (EBS)

? End-to-end packet transfer delay ? Jitter (delay variation) ? Packet loss ratio

? Differentiated Service provisioning with different priority/weight ? Premium service, time-critical real-time service, controlled service, best effort service

? Efficient Traffic Engineering for WDM optical lambda/fiber channels


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NGI with IP, MPLS and WDM Optical Network

IP Layer network

GMPLS/PSC Layer network

IP Router

GMPLS/OXC layer Network

IP Router

IP Router IP Router

LSP IP Router

IP Router

IP Router

IP Router

IP Router GMPLS PSC-LSR GMPLS OXC-LSR


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Inter-networking with GMPLS-based WDM Optical Network Internet control & management protocols (RIP, OSPF, BGP, DVMRP, MOSPF) Traffic engineering with fault management & performance management for Internet Transit Network Application

GMPLS-Signaling + OAM/LMP GMPLS-Signaling for optical network

TCP/UDP

IP

IP

IP

LSP MPLS

NIC

Host A

NIC

O-NIC (WDM)

IP Router

O-NIC O-NIC (WDM) (WDM)

PSC-LSR (Edge)

OXC

OXC

O-NIC (WDM)

O-NIC (WDM)

fiber bundle

OXC-LSR (Core)


OXC-LSR (Core)

MPLS O-NIC (WDM) PSC-LSR (Optional Core)

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Protocol Layers of Optical Internet

Application/Session Layer network (Node : aggregated traffic generator, Link : session connectivity) IP Layer network (Node : IP router, Link : IP transit connectivity) MPLS Layer network (Node : MPLS LSR (Label Switching Router), Link : Label Switched Path (LSP)) Hierarchical Multiplexing, Traffic Grooming at Extended Optical-UNI (ATM, Frame Relay, SONET/SDH, Ethernet) Optical network (Node : OADM, OXC Link : Optical WDM/ DWDM link)

Packet Switch network (Node : ATM, FR EX Link : ATM VP/VC)


TDM Network (Node : SONET ADM, MUX Link : SONET VC) 7

MPLS LSR (Label Switching Router)

IP Routing agent

OAM message

MPLS OAM

IP Routing Protocol (RIP, OSPF, BGP)

IP Routing Table MPLS Signaling agent

MPLS Signaling (CR-LDP, RSVP-TE)

Control Plane in a node IP/Label forwarding table updates Incoming IP Packets

Incoming Labeled Packets

IP Forwarding (Edge node only)

Outgoing IP Packets

FEC MPLS Label Forwarding

Outgoing Labeled Packets

Data Plane in a node APNOMS2002 Tutorial, Young-Tak Kim, Advanced Networking Technology Lab. (ANT Lab.), YeungNam Univ.

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Optical Lambda Switching and Fiber Switching IP Routing Protocols for control channel setup

LMP message

Link Management Protocol (LMP)

Link Management

IP Routing Table GMPLS Signaling Protocol for Optical Network (Wavelength allocation, optical path setup & release) Control Plane in a node

CR-LDP, RSVP-TE

switching table updates Data Plane in a node

Lambda ? 0

Lambda ? 0

Lambda / Fiber Switching Table

Lambda ? 1 ••• Lambda ? N

OSPF-TE, BGP

port 1

port 2 •••

Lambda ? 1 port 1

- Lambda Add-drop - Wavelength routing - Wavelength translating - Fiber switching

port n


••• Lambda ? N

port 2 ••• port n 9

Hierarchical Traffic Grooming in GMPLS Network Generalized MPLS Control function Packet Router(Routing) TDM Channel control function Lambda control function Fiber control function

PSC cloud

TDM cloud LSC cloud

FSC cloud

FA-PSCs (LSPPSC) FA-TDMs (LSPTDM ) FA-LSCs (LSPLSC) FA-FSCs (LSPFSC) Lambda 1

Fiber 1 Fiber Bundle/Trunk

Lambda n Fiber n


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Traffic Engineering ? Traffic Engineering ? Performance evaluation and optimization of operational networks ? Encompasses the technologies of measurement, modeling, characterization, and control of traffic

? Goal of Internet Traffic Engineering ? Facilitate efficient and reliable network operations while simultaneously optimizing network resource utilization and traffic performance ? Enhance and guarantee the QoS delivered to end users ? Optimize the resource utilization by optimized routing, efficient capacity management and traffic management ? Traffic oriented performance measures: delay, delay variation, packet loss, and throughput ? Enhanced network integrity with network survivability APNOMS2002 Tutorial, Young-Tak Kim, Advanced Networking Technology Lab. (ANT Lab.), YeungNam Univ.

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Internet Traffic Engineering ? Capacity Management ? Capacity planning, routing control, resource management ? Network resources: link bandwidth, buffer space, computational resource

? Traffic Management ? Nodal traffic control: traffic conditioning, queue management, scheduling ? Regulating traffic flow: traffic shaping, arbitration of access to network resources

? Traffic-oriented performance measures ? Delay, delay variation ? Packet loss ? Throughput


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Traffic Control and Management Functions Response Time

Long term (weeks, months)

Connection duration (sec, min, hour)

Round-trip delay (msec)

Capacity Planning, Resource provisioning Re-configuration of logical topology (traffic trunk) Network Load re-balancing Call/connection admission control Call/connection routing (constraint-based)

Dynamic source coding

Traffic parameter adjusting

Adaptive windows

Adaptive rate control Feedback Flow Control

Explicit Notification Packet Processing Time (usec)

Traffic shaping

Excess traffic marking

Traffic policing

Selective discarding

Preventive control APNOMS2002 Tutorial, Young-Tak Kim, Advanced Networking Technology Lab. (ANT Lab.), YeungNam Univ.

Reactive control 13

ITU-T I.371 Traffic Management Framework User-Network Interface (UNI) SB B-TE

TB B-NT2

B-NT1

Optional Traffic Shaping

Network A - CAC UPC - RM - PC - Others Inter-Network (NNI) Network B

TB

SB B-TE

B-NT2

B-NT1

UPC: Usage Parameter Control CAC: Connection Admission Control PC: Priority Control

- CAC - RM - PC - Others

NPC

NPC: Network Parameter Control RM: Resource Management Others: Spacing, Framing, Shaping, etc


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Internet Traffic Engineering with DiffServ and GMPLS Service Level Agreement (SLA) / Service Level Specification (SLS) Traffic Level Agreement (TLA) / Traffic Level Specification(TLS)

Internet Traffic Engineering with DiffServ or IntServ DiffServ -DiffServ Code Points (DSCPs ) - PHB (Per-Hop Behavior)

IntServ -Guaranteed Service -Controlled service - Best effort service

DiffServ-to-CR-LSP mapping DiffServ-aware MPLS Traffic Engineering - CR-LSP traffic/QoS parameters

User A

ISP 1

ISP 2

GMPLS Network

GMPLS Network

OXC/WDM Optical Backbone Network

OXC/WDM Optical Backbone Network


User B

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Traffic Engineering with DiffServ-aware-MPLS ? Differentiated Service (DiffServ) ? 7 differentiated class-types (traffic aggregates) ? QoS and traffic parameters are specified for each class-type ? Priority or Weight is assigned for each class-type ? Per-class level fine-grained optimization by DiffServ; Aggregated level optimization by MPLS LSP

? MPLS-based Traffic Engineering ? MPLS LSP provides constraint-based routing for traffic trunk provisioning ? Connection-oriented traffic trunk (CR-LSP) planning and provisioning ? Network load-balancing is possible by controlling the traffic trunk ? By using EXP (CoS) fields in MPLS LSP Shim header, differentiated packet processing (DiffServ-aware) is possible ? Efficient & flexible resource utilization with bandwidth borrowing among LSPs (traffic trunks)


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Service Level Agreement (SLA) ? Service Level Agreement (SLA) ? ? A contract between a service provider and a customer ? Specifies, usually in measurable terms, what QoS the service provider will provide

? Generic QoS parameters ? Availability ? Delivery ? Latency ? Bandwidth ? Mean Time Between Failures (MTBF) ? Mean Time to Restoration of Service (MTRS)


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Example of Service Level Specification ? Service Level Specification in TEQUILA ? Scope: the geographical/topological region over which the QoS is to be enforced; (possible topology: 1-to-1, 1-to-N, 1-to-all, N-to-1, all-to-1) ? Flow Identification: DSCP, Source, Destination, Application ? Traffic Conformance Testing: in-profile, out-profile with peak rate (P), token bucket rate (R ), bucket depth (B), Minimum packet size (M), Maximum transfer Unit (MTU) ? Marking and Shaping services prior to conformance testing ? Excess traffic treatment ? Performance parameters: delay, jitter, packet loss, throughput ? Service schedule: time of the day range, day of the week range, month of the year range, year range ? Reliability: mean down time, maximum time to repair APNOMS2002 Tutorial, Young-Tak Kim, Advanced Networking Technology Lab. (ANT Lab.), YeungNam Univ.

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Traffic / QoS Parameters of Bearer Service among IP Routers ? Traffic parameters ? Peak Data Rate (PDR) ? Average Data Rate, Sustainable Data Rate with burst tolerance ? Minimum Data Rate ? Frame rate with max. frame size

? QoS Parameters ? End-to-end transfer Delay ? Delay variance (Jitter) tolerance ? Bit/Packet/Frame loss ratio


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Closed-loop Control in Traffic Engineering Long-term optimization

Network Provisioning

Mid-term optimization

(Re-) configuration of logical topology (traffic trunk)

Real-time per- flow optimization

Router parameter setting (Bandwidth allocation, Queuing, packet scheduling)

DiffServ-aware-MPLS

DiffServ-aware-MPLS

End system A

Collect & Analysis Measurement results

End system B

Node performance monitoring

End-to-end performance measurement


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Differentiated Service (DiffServ)


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Differentiated Service ? Goal of DiffServ ? Service differentiation without scalability problem ? A scalable mechanism for categorization of traffic flow into behavior aggregates ? Each behavior aggregate is defined as a class-type by DS field in IP header ? Each class-type is treated differently by its Per-Hop Behavior (PHB) using different classification, policing, shaping, and scheduling rules. ? End user of differentiated network service should have a Service Level Agreement (SLA) with Traffic Conditioning Agreement (TCA) ? TCA defines classifier rules as well as metering, marking, discarding, and shaping rules ? Packets are classified, and possibly policed and shaped at the ingress to a DiffServ Network ? When a packet traverses the DiffSev Domain boundaries, the DS field may be remarked APNOMS2002 Tutorial, Young-Tak Kim, Advanced Networking Technology Lab. (ANT Lab.), YeungNam Univ.

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Packet Classification ? BA (Behavior Aggregate) Classifier ? Classifies packets based on the DS code-point only

? MF (Multi-field) Classifier ? Selects packets based on the value of a combination of one or more header fields ? IP packet header fields: ? Source address, destination address ? DS field ? Protocol ID ? Source Port, Destination port ? Other information, such as incoming interface


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Per Hop Behavior (PHB) ? Per-Hop Behavior (PHB) ? The externally observable forwarding behavior applied at a DS-compliant node to a DS behavior aggregate ? The means by which a node allocates resources to behavior aggregates ? Defines hop-by-hop resource allocation mechanism ? Example of PHB ? Guarantee minimal bandwidth allocation ( x % of a link or tunnel) ? Guarantee minimal bandwidth allocation (x % of a link or tunnel) with proportional fair sharing of any excess link capacity ? Buffer allocation ? Priority relative to other PHBs

? PHBs are specified as a group (PHB group) for consistency ? PHBs are implemented in nodes by means of some buffer management and packet scheduling mechanisms


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Example of DiffServ Class-type Class-type

Objective

Example

Delay

Jitter

packet Loss Ratio

NCT1/ NCT0

Minimized error, high priority

RIP, OSPF, BGP4

100 msec

U

10-3

Committed rate

111 000 / 110 000

EF

Jitter sensitive, real-time high interaction

VoIP

100 msec

50 msec

10-3

Committed rate

101 110

AF4

Jitter sensitive, real-time high interaction

Video conference

400 msec

50 msec

10-3

Committed rate & Peak rate

100 000

AF3

Transaction data, interactive

Terminal session Custom app

400 msec

U

10-3


011 000

AF2

Transaction data

Data base Web

400 msec

U

10-3


010 000

AF1

Low loss bulk data

FTP E- mail

1 sec

U

10-3


001 000

BE

Best effort

Best effort service

U

U

10-3

U

000 000

Bandwidth definition

DSCP

(Note : a) U : undefined, b) Drop precedence of AF4~AF1 : 010, 100, 110) APNOMS2002 Tutorial, Young-Tak Kim, Advanced Networking Technology Lab. (ANT Lab.), YeungNam Univ.

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Differentiated Packet Processing

Metering, Action, Algorithmic Dropping

IP Packet flow input

Packet Classifier

Smoothing (averaging) Buffer depth NCT (Network Control Traffic)

Packet Scheduling

Traffic Shaping

Expedited Forwarding (EF)

Assured Forwarding (AF)

Best Effort Forwarding (BEF)

Packet Transmission with Link Speed X (LSP : PDR/PBS, CDR/CBS+EBS)

Packet Discarding (algorithmic dropping) APNOMS2002 Tutorial, Young-Tak Kim, Advanced Networking Technology Lab. (ANT Lab.), YeungNam Univ.

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DiffServ Traffic Handler

NCT0

IP Packet Stream

Packet Classifier

EF

Single Rate TCM (CIR/CBS+EBS) Single Rate TCM (CIR/CBS+EBS) Single Rate TCM (CIR/CBS+EBS)

Per-Class-Queues drop count ? drop count ? drop count ?

AF 4

Two Rate TCM (PIR/PBS, CIR/CBS+EBS)

drop ?

AF 3


AF 2


count

AF 1


drop ? drop ? drop ? drop ?

count

BF

Scheduling/ shaping

count count

count


Priority-based Scheduler

NCT1

Metering/Marking

Rate-based Scheduler

Packet Classification

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Packet Classifier and Traffic Conditioner

Meter

Packets

Classifier

Marker


Shaper/ Scheduler

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Traffic Policing, Metering / Marking and Re-marking

Parameters Single Rate Three Color Marker (SRTCM)

CIR/CBS+E BS

Two Rate Three Color Marker (TRTCM)

PIR/PBS CIR/CBS

Red

Yellow

Green

TE(t)-B < 0

TE(t)-B ? 0 and TC(t) –B < 0

TC(t) –B ? 0

TP (t)-B < 0

TP (t)-B ? 0 and TC(t) –B < 0

TC(t) –B ? 0

(Note: B: arrived packet size, TE(t): token count of excess rate token bucket, TC(t): token count of committed rate token bucket, TP(t): token count of peak rate token bucket)


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Per Class-Type Queuing (1) : Tail-Drop Q

Buffer level

0

packet drop at buffer-full

Drop Probability 1

Queue Length Buffer Limit


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Per Class-Type Queuing (2): RED (Random Early Detection) Queue Buffer level TH max

TH min 0

Discard Probabilistic packet drop

Discard with increasing probability Pa

Do not discard

Drop Probability 1 Pmax

Pmin THmin APNOMS2002 Tutorial, Young-Tak Kim, Advanced Networking Technology Lab. (ANT Lab.), YeungNam Univ.

THmax Average Queue Length 31

Per Class-Type Queuing (3): WRED (Weighted Random Early Detection) Queue Drop Probability

1 (Note: THmin(i) = (1/2 + i/8)*THmax

Pmax (0..7)

Average Queue Length

THmin(0)

THmin(7) THmax(0… 7)

(a) Default WRED Drop Probability Configuration Drop Probability

Drop Probability

1

1

Pmax(0)

Pmax(0)

Pmax(7)

Average Queue Length THmin(0)

THmin(7) THmax(0… 7)

Average Queue Length

Pmax(7)

THmin(0) THmax(0)

(b) WRED case 1 APNOMS2002 Tutorial, Young-Tak Kim, Advanced Networking Technology Lab. (ANT Lab.), YeungNam Univ.

THmin(7) THmax(7) (c) WRED case 2 32

Per Class-Type Queuing (4): RIO (RED with In/Out-Profile) Queuing

Buffer level (average In_profile)

0

Avg_in

In-Profile (Green) Out-Profile (Red)

Avg_total Buffer level (average_Total)

Drop Probability 1

Probabilistic packet drop

Pmax_out

Pmin_in

Pmin_out min_out APNOMS2002 Tutorial, Young-Tak Kim, Advanced Networking Technology Lab. (ANT Lab.), YeungNam Univ.

Pmax_in

min_in max_out max_in Average Queue Length 33

DiffServ Packet Scheduler (1) ? Priority-based, Weight-based Packet Scheduler

priority

weight

priority

weight

priority

Priority Priority Scheduler Scheduler

priority

(a) Priority-based Scheduler

weight

Rate-based Rate-based scheduler scheduler (WRR (WRRoror WFQ) WFQ)

weight

(b) Weight-based Scheduler

(c) Hierarchical Packet Scheduler APNOMS2002 Tutorial, Young-Tak Kim, Advanced Networking Technology Lab. (ANT Lab.), YeungNam Univ.

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DiffServ Packet Scheduler (2) ? Hierarchical Packet Scheduler priority NCT1

priority

NCT0

priority Min rate

AF4

Min rate

AF3

Min rate

AF2

Min rate

Rate-based Rate-based scheduler scheduler (WRR (WRRororWFQ) WFQ)

priority

Priority Priority Scheduler Scheduler

TrafficShaper Shaper Traffic

EF

shaping rate (PDR/PBS, CDR/CBS+EBS)

AF1 priority BF


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Traffic Shaping

Committed rate Token bucket

WFQ/FIFO Configured rate Classify Measure

Packet Scheduler

Incoming packets

Outgoing packets

No match Queuing method


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Multi-Protocol Label Switching (MPLS)


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MPLS (Multi-Protocol Label Switching)

Ingress Node label i IP datagram

source A

destination B

label j

IP datagram

label k

label m Egress Node

MPLS Domain Network


38

Label Distribution Protocol (LDP) ? Labels - short fixed identifier, meaningful only at the segment between LSR pair - assigned according to FEC (Forwarding Equivalent Class)

? Label assignment & distribution - assigning label(s) to a FEC : binding a label L to a particular FEC F by down stream LSR switch - Label distribution by i) upstream node, ii) down stream node, or iii)downstream-on-demand label distribution Bind

Ru Upstream LSR check incoming label

Packet

Label

Rd

assign outgoing label check incoming label


Downstream LSR

assign outgoing label

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Hierarchical Label Stacking Packet P level (m+k) Packet P level (m-1)

Packet P, level (m)

LSP ingress (push a label) R1 R1

Packet P level (m-1)

swapping

swapping ??????

Rn-1 Rn-1

??????

Ri+1 Ri+1

R2 R2

Ri Ri

LSP ingress (push a label)

LSP egress (pop the label) Rn Rn

LSP egress (pop the label)


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MPLS Traffic Engineering ? Connection-oriented LSP (Label Switched Path) ? Constraint-based Routing ? Traffic Engineering (TE) requirements of LSP ? Constraint-based Shortest Path First (CSPF)

? Forwarding Equivalent Class (FEC): multiple ? source IP address range : min, max ? destination IP address range : min, max ? source port range : min, max ? destination port range : min, max ? service type

? MPLS FEC-to-NHLFE (FTN) structure ? FEC : Forwarding Equivalent Class ? NHLFE : Next Hop Label Forwarding Entity


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Constraint-based Routing in MPLS ? Traffic parameters of the constraint-based routing for LSP ? bandwidth of LSP : peak data rate, committed data rate

? Modification of Link State Database for constraint-based routing ? traffic parameter ? available bandwidth at each link : number of lambda channels, bandwidth of each lambda channels

? Additional QoS parameter ? propagation delay

? Combined cost metric

? Modification of OSPF shortest path routing ? constraint-based routing with traffic parameters: bandwidth, QoS, resource class, class of failure protection ? SRLG (Shared Risk Link Group)


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Constraint-Routed LDP (CR-LDP)

OSPF-TE/ BGP

CR-LDP

OSPF-TE/ BGP

CR-LDP

OAM

CR-LDP

OSPF-TE/ BGP

OAM

TCP/UDP

CR-LDP

OSPF-TE/ BGP

OAM

TCP/UDP

OAM

TCP/UDP

TCP/UDP

IP

IP

IP

IP

NIA(ONIC)

NIA(ONIC)

NIA(ONIC)

NIA(ONIC)

O-NIC

WDM

O-NIC

MPLS-LSR (ingress) CR- LDP (label

WDM

MPLS-LSR (intermediate) request)

connection request from TE manager

appi CR-LDP (label m

ng)

CR- LDP (label

O-NIC

WDM

O-NIC

MPLS-LSR (egress)

MPLS-LSR (intermediate) request)

apping) CR-LDP (label m


CR- LDP (label

request)

appi CR-LDP (label m

ng)

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CR-LDP Traffic Parameters Flags control “negotiability” of parameters U

F

Traf. Param. TLV

Flags

Frequency

Length Reserved

Weight

Peak Data Rate (PDR) Peak Burst Size (PBS) Committed Data Rate (CDR) Committed Burst Size (CBS) Excess Burst Size (EBS)

32 bit fields are short IEEE floating point numbers Any parameter may be used or not used by selecting appropriate values

Frequency constrains the variable delay that may be introduced Weight of the CRLSP in the “relative share” Peak rate (PDR+PBS) maximum rate at which traffic should be sent to the CRLSP Committed rate (CDR+CBS) the rate that the MPLS domain commits to be available to the CRLSP Excess Burst Size (EBS) to measure the extent by which the traffic sent on a CRLSP exceeds the committed rate


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RSVP-TE ? RSVP-TE Message ? Path, Resv ? PathTear, ResvTear ? PathErr, ResvErr ? ResvConf, Hello, Notify

Re sv

sv e R

Pa th

ta Da

sv Re

ta Da th Pa

Receiver C

Da ta

th Pa

Sender A

Router Router R1 R1

Path

Router Router R2 R2

Data

Sender B


Pa th Re sv

Da ta

Receiver D

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Traffic Policing for CR-LSP

? Three token buckets : Peak Rate, Committed Rate, Excess Token count

Initial value

Increment rate (per second)

TP

PBS (Peak Bucket Size)

PDR (Peak Data Rate)

TC

CBS (Committed Burst Size)

CDR (Committed Data Rate)

TE

EBS (Excess Burst Size)

CDR (Committed Data Rate)

? When a packet of size B bytes arrives at time t, ? if TP (t) – B ? 0, the packet is not in excess of the PDR => TP (t) = TP (t) – B else the packet is in excess of the PDR => Packet Marking (and optionally discarding) ? if TC(t) – B ? 0, the packet is not in excess of the CDR => TC (t) = TC(t) – B else if TE(t) – B ? 0, the packet is in excess of the CDR but is not in excess of the EBS => TE(t) = TE(t) – B else : the packet is in excess of both the CDR and EBS => Packet Marking (and optionally discarding)


46

Discarding Options of Marked Packet ? Simple packet discarding policy (example) ? if any packet is in excess of the PDR, then discard the packet ? if any packet is in excess of both the CDR and EBS, then mark the packet and discard considering the relative “packet drop precedence” of the packet

? Other considerations ? relative packet drop precedence of Assured Forwarding (AF) ? relative share (defined by weight) of the possible excess bandwidth above its committed rate among CR-LSPs ? Packet scheduling for EF (Expedited Forwarding) packet to minimize delay & jitter ? optional traffic shaping


47

MPLS OAM ? IETF draft document : “OAM Functionality for MPLS Networks (Neil Harrison et. al, Expr. date : Aug. 2001)” ? OAM (Operation and Maintenance) for the user-plane in MPLS network ? CV (connectivity verification) OAM Function ? used to detect defects related to misrouting of LSPs as well as link and nodal failure ? if connectivity error is detected, it may trigger protection switching of the working path to the pre-established protection path

? Performance OAM Function ? FDI (Forward Defect Indicator)/ BDI (Backward Defect Indicator) OAM Function ? triggers fault management function & LSP restoration/rerouting


48

MPLS OAM Packets (Example) 0 1 2 3 01234567890123456789012345678901 OAM Type OAM Function

PDU Length

Ingress LSR Identifier Egress LSR Identifier LSP Identifier

0 1 2 3 01234567890123456789012345678901 OAM Type OAM Function

Loop-back start LSR Identifier Loop-back end LSR Identifier

Sequence Number Time Stamp

PDU Length

LSP Identifier Loop-back operation mode

Number of Total Transmitted Packets

Optional data

Total Transmitted Data Size [Byte] Optional Information (b) Loopback Test OAM (a) Performance Management OAM


49

IP Performance Measurements ? Connectivity (RFC 2678) ? Instantaneous unidirectional connectivity ? Instantaneous bi-directional connectivity ? Interval unidirectional connectivity ? Interval bi-directional connectivity ? Interval temporal connectivity

? Delay metric for IPPM (RFC 2679) ? One-way delay Poisson stream

? Packet loss metric for IPPM (RFC 2680) ? One-way packet loss Poisson stream


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Fault Management Flow (Example)

TCP/UDP IP MPLS

PHY

LER 110 (ingress node)

PHY

LSR 120

LSR 121

working LSP backup LSP

TCP/UDP IP MPLS PHY

LSR 220

TE Agent

OSPF-TE/ BGP CR-LDP

link failure detection

OSPF-TE/ BGP CR-LDP TCP/UDP IP MPLS PHY

LSR 221


OSPF-TE/ BGP CR-LDP TCP/UDP IP MPLS

TE Agent

PHY

TCP/UDP IP MPLS

link failure notification

TE Agent

TE agent controls the rerouting

OSPF-TE/ BGP CR-LDP TE Agent

OSPF-TE/ BGP CR-LDP TE Agent

TCP/UDP IP MPLS

TE Agent

OSPF-TE/ BGP CR-LDP

PHY

LER 211 (egress node)

51

MPLS Fault Management (FM) OAM LSR120

LSR130

LSR140

LER 110

LER 150

timeout (a) Node-by-node sequential loop-back test

timeout (b) Roll-call loop-back test


52

Constraint-based Shortest Path First (CSPF) Routing

OSPF_TE (2) Opaque LSA information Link State - TLV information setup using Information TLVInfo Object (TLV info DB) -Construct Opaque LSA Table at LSDatabase Object

(1) TE metric update in each interface (get-TE-interface())

Truncated Link State Information (satisfying the constraints)

(3) TE Constraints of connection setup

MPLS Network Interface Info.

Dijstra’s Shortest Path First Algorithm

-Interface information Base * Interface Info : * TE Metrics :


53

OSPF, CR-LDP and Resource Allocation Traffic Engineering Manager (Backbone Trunk LSP Information) MPLS LSR or OXC-LSR Constraint-based SPF(CSPF) Routing Shortest Path Finding (Dijkstra) OSPF Link status information gathering

Traffic Engineering Agent (LDP Bandwidth Update)

CR-LDP / RSVP-TE Signaling

Resource Management (Bandwidth allocation, Wavelength allocation, Resource status table)


54

DiffServ-aware-MPLS Traffic Engineering


55

DiffServ-over-MPLS Traffic Engineering

DiffServ IP Packet Flow Host

Classifier Meter Actions (drop)

Host IPIP Router Router

Queuing

Shaping / Mapping to LSP

Host

Packet Scheduling

DiffServ-aware DiffServ-aware MPLS MPLSLSR LSR


CR-LSP (Traffic Parameters : - Peak Data Rate(PDR) - Peak Burst Size (PBS) - Committed Data Rate (CDR) - Committed Burst Size (CBS) - Excess Burst Size (EBS) - Weight - Resource Class / Color )

56

MPLS support of DiffServ ? E-LSP (Exp-inferred-LSPs) ? LSPs which can transport multiple Ordered Aggregates ? the EXP field of the MPLS shim header conveys to the LSR the PHB to be applied to the packet (conveying both information about the packet’s scheduling treatment and its drop precedence)

? L-LSP (Label-only-inferred-LSPs) ? only transports a single Ordered Aggregates ? the packet’s scheduling treatment is inferred exclusively from the packet’s label value ? the packet’s drop precedence is conveyed in the EXP field of the MPLS shim header or in the encapsulating link layer specific selective drop mechanism (ATM, FR, 802.1)


57

E-LSP (Exp-inferred-LSPs) Mapping Policy-based MPLS Traffic Trunk (TT) Management Policy 1: “During business hour, increase bandwidth of gold_TT by 100%” Policy 2 : “During off-business hour, decrease bandwidth of gold_TT by 50%”

best-effort controlled traffic traffic

VPN traffic

Service class

traffic type rt/nrt-VBR traffic (data, Web/HTTP, FTP, E-mail)

DiffServ Classes in a Class-type N BE (default) AF1, 2, 3, 4

CBR real-time traffic (voice/video)

EF (or AF1)

VPN control traffic

NCT(11x000)

CR-LSP (Resource class = “gold”) for Class-type N

CR-LSP (Resource class = “silver”) CR-LSP (Resource class = “bronze”)


Physical Transmission Medium (Electrical, Optical, Microwave Satellite) Maximum reservable aggregate BW Allocated BW Un-reserved BW 58

L-LSP (Label-only-inferred-LSPs) mapping

Client B

Client A

Service User

traffic type rt/nrt-VBR traffic (data, Web/HTTP, FTP, E-mail)

DiffServ Classes in a Class-type N BE (default)

CR-LSP for Class-type BE CR-LSP for Class-type AF 3x, 4x

AF1, 2, 3, 4

CR-LSP for Class-type AF 2x


EF (or AF1)

VPN control traffic

NCT(11x000)

CR-LSP for Class-type AF 1x

rt/nrt-VBR traffic (data, Web/HTTP, FTP, E-mail)

BE (default)

CR-LSP for Class-type EF CR-LSP for Class-type NCT

Physical Transmission Medium (Electrical, Optical, Microwave Satellite) Maximum reservable aggregate BW

AF1, 2, 3, 4

Allocated BW


EF (or AF1)

Un-reserved BW

VPN control traffic

NCT(11x000)


59

Mapping DiffServ Class Type into E-LSP ? Mapping DiffServ Class-type into MPLS E-LSP ? One DiffServ Class-type contains multiple DiffServ Classes ? 4 Assured Forwarding (AF) with 3 packet drop precedence at each AF => 12 DSCPs : DSCP {001, 010, 011, 100} {010, 100, 110} ? Expedited Forwarding (EF) for minimized delay & jitter : DSCP 101 110 ? Network Control Traffic : DSCP “11x 000” ? Default Forwarding for Best Effort (BE) traffic

? E-LSP uses EXP field (3-bit) of MPLS Shim header ? E-LSP allow multiple OAs (ordered aggregates) to be carried over a single LSP ? 8 different PHBs can be specified (one PHB per each ordered aggregate (OA) in the ELSP)


60

Usefulness of E-LSP ? It is easier to create end-to-end services for a customer if a single LSP is used, instead of setting up, maintaining, administering and monitoring multiple LSPs (as in L-LSP) – one for each OA (ordered aggregate) of the customer’s traffic. ? E-LSPs reduce the number of LSPs needed to deploy end-toend services in a network. ? Path protection and switching mechanisms are more easily applied to a single LSP than a group of related LSPs. ? Bandwidth borrowing among the OAs (using a single LSP) of a customer while restricting bandwidth borrowing between customers. APNOMS2002 Tutorial, Young-Tak Kim, Advanced Networking Technology Lab. (ANT Lab.), YeungNam Univ.

61

Example Mapping of EXP and PHB

DSCP Class (DSCP)

EXP code (suggested)

Best Effort (000 000)

000

AF 1, High Drop Precedence (001 110)

001

AF 2, Med Drop Precedence ( 010 100)

010

AF 3, Med Drop Precedence ( 011 100)

011

AF 4, Low Drop Precedence (100 010)

100

Expedited Forwarding (EF) : (101 110)

101

Network Control Traffic (110 000) (User-to-user control traffic) Network Control Traffic (111 000)

Per-Hop-Behavior (suggested) Default Forwarding with best effort (highest drop precedence) Assured Forwarding 1, High Drop Precedence for non-real time bulk data transfer Assured Forwarding 2, Med Drop Precedence for non-real time ABR Assured Forwarding 3, Med Drop Precedence for non-real time VBR data Assured Forwarding 4, Low Drop Precedence for real-time VBR data Minimized delay & jitter for Real-time CBR traffic

110

Minimized error, high priority

111

Minimized error, highest priority


62

MPLS LSP Stacking and Bandwidth Borrowing

re-allocation of excess bandwidth in proportion to the weight

Tunnel LSP Excess available bandwidth

LSP i (weight = x) LSP j (weight = y)

LSP k (weight = z)


63

(a) Hierarchy of LSP

Packet Scheduler

Packet Sched Packet Sched

Hierarchical Packet Scheduling and Recursive Bandwidth Borrowing

(b) Hierarchy of packet scheduler

Available Excess Bandwidth

User LSP

Inner Tunnel LSP

Outer Tunnel LSP

(C) Recursive Bandwidth Borrowing APNOMS2002 Tutorial, Young-Tak Kim, Advanced Networking Technology Lab. (ANT Lab.), YeungNam Univ.

64

Fault Restoration in MPLS Network


65

Protection Switching Types

(a) 1:1 Path Restoration

(b) 1+1 Path Restoration

working path(N)

working path(N)

...

... backup path (c) 1:N Path Restoration

backup path(M)

..

..

(d) M:N Path Restoration


66

Link-, Path-, Span-Restoration

(a) Normal Operation

(b) Path Switching/protection

(c ) Span Protection

(d) Link/Line Protection


67

Path Restoration vs. Segment-Restoration

(a) Link Restoration

(b) 1:1 Path Restoration

(c) 1+1 Path Restoration

(d) Segment Restoration APNOMS2002 Tutorial, Young-Tak Kim, Advanced Networking Technology Lab. (ANT Lab.), YeungNam Univ.

68

Ring-based protection switching algorithms ? SONET Self-healing Rings ? UPSR (Uni-directional Path-Switched Ring) ? 1+1 protection, Selection at receiver node ? Protection ring has reverse direction ? Used in access network

? BLSR (Bi-directional Line Switched Ring) ? Also referred to as shared protection ring (SPRING) ? 2-fiber BLSR or 4-fiber BLSR ? Used in core network Working & Protection Working & Protection Working Ring Protection Ring

(a) UPSR

(b) BLSR


69

Restoration using p-Cycles

A span on the cycle fails – 1 Restoration Path, BLSR-like

A p-cycle

A span off the p-cycle fails – 2 Restoration Paths, Mesh-like


70

Shared Risk Link Group (SRLG) ? Examples of SRLG id in Optical Link link-1 (SRLG-4) link-2 (SRLG-5)

?1 ?2 ?3 ?4 ?5 ?6

Working path Backup path

bundle (SRLG-2) link-3 (SRLG-3)

OXC-1 conduit

OXC-4

Conduit (SRLG-1)

bundle fiber

OXC-2

OXC-3

OXC-5

OXC-6


71

Differentiated Fault Restoration Policy ? Differentiated Backup Path Reservations (Example) MPLS Service Class

Bandwidth Reservation (%)

Setup Priority

Preemption Priority

Application

Platinum

100, 1+1

Highest

Highest

High Priority VPN

Gold

100, 1:1

Higher

Higher

VPN

Silver

80, 1:1

Normal

Normal

Premium service

Bronze

50, 1:1

Lower

Lower

Controlled traffic

Best effort

0

Lowest

Lowest

Best Effort

? Backup Path Utilization ? Reservation with NO Traffic ? Reservation with Lower Priority Traffic ? Allow working path traffic at restoration


72

DiffServ-aware-MPLS Traffic Engineering of Cisco Routers


73

DiffServ Functions in Commercial Routers ? DiffServ Capability of Cisco Router ? DiffServ Queuing ? Flow-based WFQ, Flow-based Distributed WFQ ? Class-based WFQ ? Priority Queuing

? Packet Scheduling ? Modified Weighted Round Robin (MWRR) ? Modified Deficit Round Robin (MDRR)

? Congestion Avoidance and Packet Drop Policy ? RED, WRED, Flow WRED

? Traffic Class Definition (class-map): IP address, precedence, DSCP, MAC address, interface, protocol ? Policy Definition (policy-map): edge QoS feature (rate-limiting, rateshaping, IP precedence, DSCP setting), core QoS feature (WFQ, WRED)


74

MPLS Functions in Commercial Router ? MPLS functions in Cisco Router ? TE-RSVP to support LSP path signaling ? MPLS QoS defined by the CoS field of Shim header ? Class 0 (available) ? Class 1 (Standard) ? Class 2 (Premium) ? Class 3 (Control)

? MPLS Traffic Engineering Tunnel ? Priority ? Bandwidth ? Path option: dynamic routing, explicit routing

? MPLS-VPN ? VPN Routing and Forwarding (VRF) ? MPLS VPN QoS: premium and standard service levels


75

Network Management System to support DiffServ-aware-MPLS Traffic Engineering GUI GUI Operator Operator Interface Interface

GUI GUI Operator Operator Interface Interface

NMS Configuration Configuration Mgmt Mgmt

Connection Connection Mgmt Mgmt

Performance Performance Mgmt Mgmt

Fault Fault Mgmt Mgmt

Performance Performance Mgmt Mgmt

Fault Fault Mgmt Mgmt

IIOP

EMS Configuration Configuration Mgmt Mgmt

Connection Connection Mgmt Mgmt

IIOP GIA

Service Service Service Service Object Object Object Object Service Service classifier classifier

CLI Interface

SNMP Interface

Telnet TelnetInterface Interface parser parser

SNMP SNMP-Get -Get SNMP SNMP-GetNext -GetNext SNMP SNMP-Set -Set

Transceiver Transceiver TELNET (TCP Port 23)

RMA Interface

SNMP

Connectivity ConnectivityCheck Check Traffic TrafficMonitoring Monitoring

RMA

SOCKET

Connectivity ConnectivityCheck Check (ICMP) (ICMP) Traffic TrafficMonitoring Monitoring (Packet (PacketCapture) Capture)

DNS Customer Premise Network CPN(Intranet)

Internet Transit Network


Customer Premise Network CPN(Intranet)

76

Explicit establishment DiffServ-aware-LSP

Constraint-based Shortest Path First (CSPF) Routing

NMS

EMS

EMS

CPN A

DiffServ -aware MPLS LER

MPLS Transit LSR

MPLS Transit LSR

EMS

MPLS Transit LSR

DiffServ -aware MPLS LER

CPN B

DiffServ-aware MPLS Network


77

Performance measurement of QoS, Transfer Rate and Connectivity checks transfer rate 450000 400000 350000

bps

300000 250000

AF BF EF

200000 150000 100000 50000

86

81

76

71

66

61

56

51

46

41

36

31

26

21

16

6

1

11

0

(a) Traffic monitoring

time(sec)

(d) Transmission Data rate Drop rate 300000

250000

200000

bps

(b) Traffic analysis (per Protocol)

AF BF EF

150000

100000

85

81

77

73

69

65

61

57

53

49

45

41

37

33

29

25

21

17

9

5

1

0

13

50000

time(sec)

(e) Packet Drop rate (c) IP Connectivity check APNOMS2002 Tutorial, Young-Tak Kim, Advanced Networking Technology Lab. (ANT Lab.), YeungNam Univ.

78

Test Networking Configuration PC 1 PC 2

PC 3

Cisco 3620/ 7204

Cisco 3620/ 7204

Cisco 7204

PC 4

(a) Physical topology Flow 1: PC 1 to PC 3 200 Kbps CBR Flow 2: PC 1 to PC 3 300 ~ 500 Kbps VBR Flow 3: PC 2 to PC 4 200 Kbps CBR Flow 4: PC 2 to PC 4 300 ~ 500 Kbps VBR

200Kbps 300Kbps

LSP 1-3 500 Kbps Traffic Trunk LSP 1 Mbps

200Kbps 300Kbps

LSP 2-4 500 Kbps

(b) Logical topology APNOMS2002 Tutorial, Young-Tak Kim, Advanced Networking Technology Lab. (ANT Lab.), YeungNam Univ.

79

Test Results ? Test Configuration 500 450 400 350 300

Kbps

? Flow 1, 3 (200Kbps CBR), rate limit= 200 Kbps, Burst size Bc=5Kbytes, Be=5Kbytes

Input Data Rate

Flow1 Flow2

250 200

? Flow 2, 4 (300~500 Kbps VBR), rate limit= 300 Kbps, Burst size Bc=5Kbytes, Be=5Kbytes

150 100 50

145

136

127

118

109

91

100

82

73

64

55

46

37

28

19

10

1

0

Time[sec]

? MPLS LSP 1-3: Bandwidth=500Kbps, Burst Size

Received Data Rate 500 450

? MPLS LSP 2-4: Bandwidth= 500Kbps

350 300

Kbps

? DiffServ-aware MPLS packet scheduling

400

Flow1 Flow2

250 200 150 100 50


145

137

129

121

113

105

97

89

81

73

65

57

49

41

33

25

17

9

0

1

? Traffic generation model: fixed packet size

Time[sec]

80

Concluding Remarks ? Networking Model of Next Generation Optical Internet ? Networking with IP, MPLS and WDM Optical Network ? Required features: guaranteed QoS, differentiated service provisioning, efficient traffic engineering

? DiffServ-aware-MPLS Traffic Engineering ? Per-class level fine-grain optimization by DiffServ ? Aggregated level optimization by MPLS LSP ? Connection-oriented traffic trunk (CR-LSP) planning and provisioning for logical topology ? Network-wide periodic load re-balancing is possible for increased network throughput & performance ? Efficient and flexible resource utilization with bandwidth borrowing among CR-LSPs ? Contemporary commercial routers are supporting DiffServ and MPLS capabilities.


81

References [1] IETF RFC 3272, Overview and Principles of Internet Traffic Engineering, May 2002. [2] IETF Internet Draft, Traffic Engineering & QoS Methods for IP-, ATM-, & TDM-based Multiservice Networks, October, 2001. [3] IETF Internet Draft, Network Survivability Considerations for Traffic Engineered IP Networks, IETF draft-owens-te-network-survivability-03.txt, May 2002. [4] IETF Internet Draft, A Traffic Engineering MIB, draft-ietf-tewg-mib-02.txt. [5] IETF Internet Draft, Requirements for support of Diff-Serv-aware MPLS Traffic Engineering, June 2002. [6] IETF Internet Draft, TE LSAs to extend OSPF for Traffic Engineering, January 4, 2002. [7] IETF Internet Draft, Applicability Statement for Traffic Engineering with MPLS, August 2002. [8] IETF Internet Draft, A Framework for Internet Traffic Engineering Measurement, March 2002. [9] IETF Internet Draft, Network Hierarchy and Multilayer Survivability, July 2002. [10] IETF Internet Draft, Protocol extensions for support of Diff-Serv-aware MPLS Traffic Engineering, June, 2002. [11] IETF Internet Draft, Use of IGP Metric as a second TE Metric, March, 2002 [12] IETF Internet Draft, Alternative Technical Solution for MPLS DiffServ TE, August 2001.


82

[13] IETF RFC 2475, An Architecture for Differentiated Services, December 1998. [14] IETF RFC 2702, Requirements for Traffic Engineering Over MPLS, September 1999. [15] IETF RFC 2330, Framework for IP Performance Metrics, May 1998. [16] IETF RFC 3031, Multi-Protocol Label Switching (MPLS) Architecture, January 2001. [17] IETF RFC 3270, Multi-Protocol Label Switching (MPLS) Support of Differentiated Services, May 2002. [18] IETF RFC 3209, RSVP-TE: Extensions to RSVP for LSP Tunnels, December 2001. [19] IETF Draft, “MPLS Support of Differentiated Services using E-LSP,” S. Ganti et. al, April 2001. [20] IETF RFC 2836, “Per-Hop-Behavior Identification Codes,” S. Brim et. al, May 2000. [21] IETF Draft, “An Expedited Forwarding PHB (Updates RFC 2598),” Bruce Davie et. al, April 2001. [22] IETF RFC 2597, “Assured Forwarding (AF) PHB Group,” J. Heinanen et. al, June 1999. [23] IP Quality of Service – The complete resource for understanding and deploying IP quality of service for Cisco networks, Srinivas Vesesna, Cisco Press, 2001. [24] MPLS and VPN Architectures – A Practical guide to understanding, designing and deploying MPLS and MPLS-enabled VPNs, Ivan Pepelnjak and Jim Guichard, Cisco Press, 2001.


83

Thank You !!! Youngtak Kim, Ph.D., Associate Professor Dept. of Information and Communication Engineering, College of Engineering, Yeungnam University (Tel: +82-53-810-2497, Fax: +82-53-814-5713, E-mail: [email protected])


84

DiffServ-aware-MPLS Networking - APNOMS

DiffServ-aware-MPLS Networking - APNOMS

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