DiffServ-aware-MPLS Networking: a Promising Traffic Engineering for Next Generation Internet (NGI)

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

DiffServ-aware-MPLS Networking:a Promising Traffic Engineering for

Next Generation Internet (NGI)

DiffServ-aware-MPLS Networking:a Promising Traffic Engineering for


2002. 9. 25.

Youngtak KimAdvanced Networking Technology Lab. (ANT Lab.)

Dept. of Information & Communication Engineering,

YeungNam University, Korea

([email protected])


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


Networking Model and Traffic Engineering of



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

Required Features of Next Generation Internet


GMPLS/OXC layer Network

GMPLS/PSC Layer network

IPRouter

IP Layer network

IPRouter

IPRouter

IPRouter

IPRouter

IPRouter

IPRouter

IPRouter

IPRouter

LSP

GMPLS PSC-LSR

GMPLS OXC-LSR

NGI with IP, MPLS and WDM Optical Network


Inter-networking with GMPLS-based WDM Optical Network

GMPLS-Signaling + OAM/LMP

NIC

IP

TCP/UDP

Application

Host A

LSP

fiberbundle

PSC-LSR(Optional Core)

O-NIC(WDM)

MPLS

NIC

IP

IP Router

O-NIC(WDM)

PSC-LSR(Edge)

IP

MPLS

O-NIC(WDM)

O-NIC(WDM)

GMPLS-Signaling for optical network

Internet control & management protocols(RIP, OSPF, BGP, DVMRP, MOSPF)

Traffic engineering with fault management & performance managementfor Internet Transit Network

O-NIC(WDM)

OXC-LSR(Core)

OXC

O-NIC(WDM)

OXC-LSR(Core)

OXC


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))

Optical network(Node : OADM, OXCLink : Optical WDM/

DWDM link)

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

TDM Network(Node : SONET ADM, MUX

Link : SONET VC)

Hierarchical Multiplexing, Traffic Grooming at Extended Optical-UNI(ATM, Frame Relay, SONET/SDH, Ethernet)


MPLS LSR (Label Switching Router)

Data Plane in a node

IP Forwarding (Edge node only)

MPLS Label Forwarding

Outgoing IP Packets

Outgoing Labeled Packets

Incoming IP Packets

Incoming Labeled Packets

IP/Label forwarding table updates

Control Plane in a node

IP Routing agent

MPLS Signaling agent

IP Routing Table

IP Routing Protocol(RIP, OSPF, BGP)

MPLS Signaling(CR-LDP, RSVP-TE)

MPLSOAMOAM message

FEC


Optical Lambda Switching and Fiber Switching

OSPF-TE, BGP

CR-LDP, RSVP-TE

switching table updates

Data Plane in a node

Lambda / Fiber Switching Table

port 1

Lambda 0

Lambda 1

Lambda N

• • •

port 2

• • •

port 1

Lambda 0

Lambda 1

Lambda N

• • •

port 2

• • •

port n port n

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

IP Routing Protocols for control channel setup

GMPLS Signaling Protocol forOptical Network

(Wavelength allocation, optical path setup & release)

IP Routing TableLink

ManagementProtocol(LMP)

Control Plane in a node

Link Management

LMP message


Hierarchical Traffic Grooming in GMPLS Network

FSC cloudLSC cloudTDM cloudPSC cloud

Fiber 1

Fiber n

Lambda 1

Lambda n

FA-FSCs (LSPFSC)

FA-LSCs (LSPLSC)

FA-TDMs (LSPTDM)

FA-PSCs (LSPPSC)

Fiber Bundle/Trunk

Packet Router(Routing)

TDM Channel control functionLambda control function

Fiber control function

Generalized MPLS Control function


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


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


Traffic Control and Management Functions

Feedback Flow Control

Traffic policing

Traffic shaping

Traffic parameteradjusting

Selective discarding

Adaptive windowsAdaptive rate control

Dynamic source coding

Call/connection routing(constraint-based)

Call/connection admission control

Capacity Planning, Resource provisioning

Re-configuration of logical topology (traffic trunk)

Network Load re-balancing

Long term(weeks, months)

Connection duration(sec, min, hour)

Round-trip delay(msec)

Packet ProcessingTime (usec)

Excess traffic marking

Preventive control Reactive control

Explicit Notification

Response Time


ITU-T I.371 Traffic Management Framework

UPC: Usage Parameter ControlCAC: Connection Admission ControlPC: Priority Control

NPC: Network Parameter ControlRM: Resource ManagementOthers: Spacing, Framing, Shaping, etc

B-TE B-NT2 B-NT1

SBTB

Inter-Network(NNI)

NPC

- CAC- RM- PC- Others

Network B

B-TE B-NT2 B-NT1

User-Network Interface(UNI)

Optional TrafficShaping

UPC- CAC- RM- PC- Others

Network ASB TB


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-aware MPLS Traffic Engineering- CR-LSP traffic/QoS parameters

UserA

ISP 1 ISP 2

UserB

OXC/WDM Optical Backbone Network

GMPLS Network

OXC/WDM Optical Backbone Network

GMPLS Network

DiffServ-to-CR-LSP mapping

Internet Traffic Engineering with DiffServ and GMPLS


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 processin

g (DiffServ-aware) is possible

Efficient & flexible resource utilization with bandwidth borrowing among LSPs (traffi

c trunks)


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)


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


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

Traffic / QoS Parameters of Bearer Service among IP Routers


Closed-loop Control in Traffic Engineering

Collect &Analysis

Measurementresults

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

Network Provisioning

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

Real-time per-flowoptimization

Mid-termoptimization

Long-termoptimization

End systemA

End systemB

DiffServ-aware-MPLS DiffServ-aware-MPLS

End-to-end performance measurement

Node performance monitoring


Differentiated Service (DiffServ)


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 re-marked


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


Per Hop Behavior (PHB)

Per-Hop Behavior (PHB) The externally observable forwarding behavior applied at a DS-compliant n

ode 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


Example of DiffServ Class-type

Class-type Objective Example Delay JitterpacketLossRatio

Bandwidthdefinition

DSCP

NCT1/NCT0

Minimized error, high priority

RIP, OSPF, BGP-4

100 msec

U 10-3 Committed rate

111 000 /110 000

EFJitter sensitive, real-time high

interactionVoIP

100 msec

50 msec

10-3 Committed rate

101 110

AF4Jitter sensitive, real-time high

interactionVideo conference

400 msec

50 msec

10-3

Committed rate & Peak

rate100 000

AF3Transaction data,

interactiveTerminal session

Custom app400 msec

U 10-3


rate011 000

AF2 Transaction dataData base

Web400 msec

U 10-3


rate010 000

AF1 Low loss bulk dataFTP

E-mail1

secU 10-3


rate001 000

BE Best effortBest effort

serviceU U 10-3 U 000 000

(Note : a) U : undefined, b) Drop precedence of AF4~AF1 : 010, 100, 110)


Differentiated Packet Processing

NCT (Network Control Traffic)

Packet Transmissionwith Link Speed X(LSP : PDR/PBS,

CDR/CBS+EBS)

Packet Scheduling

Expedited Forwarding (EF)

Assured Forwarding (AF)

Best Effort Forwarding (BEF)

Traffic Shaping

Packet Discarding

(algorithmic dropping)

Pac

ket

Cla

ssif

ier

Smoothing (averaging)

Buffer depth

IP Packetflow input

Met

erin

g, A

ctio

n, A

lgor

ithm

ic D

ropp

ing


DiffServ Traffic Handler

IP PacketStream

Pac

ket C

lass

ifie

r

AF 4 Two Rate TCM(PIR/PBS, CIR/CBS+EBS)

NCT1 Single Rate TCM(CIR/CBS+EBS)

NCT0 Single Rate TCM(CIR/CBS+EBS)

EF Single Rate TCM(CIR/CBS+EBS)




BF

drop?

count

drop?

count

drop?

count

drop?

count

drop?

count

drop?

count

drop?

count

drop?

PacketClassification

Metering/Marking Per-Class-Queues Scheduling/shaping

Rat

e-ba

sed

Sch

edul

er

Pri

orit

y-ba

sed

Sch

edul

er

count


Packet Classifier and Traffic Conditioner

Classifier MarkerShaper/

Scheduler

Meter

Packets


Traffic Policing, Metering / Marking and Re-marking

Parameters Red Yellow Green

Single RateThree Color Marker

(SRTCM)

CIR/CBS+EBS

TE(t)-B < 0TE(t)-B 0

andTC(t) –B < 0

TC(t) –B 0

Two RateThree Color Marker

(TRTCM)

PIR/PBSCIR/CBS

TP(t)-B < 0TP(t)-B 0

andTC(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)


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

packet dropat buffer-full

Buffer level

0

Drop Probability

Queue LengthBuffer Limit

1


Per Class-Type Queuing (2): RED (Random Early Detection) Queue

Drop Probability

Average Queue LengthTHmin THmax

1

Pmax

Pmin

Probabilisticpacket drop

Buffer level

TH minTH max

Discard Discard with increasing probability Pa

Do not discard

0


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

Drop Probability

Average Queue Length

THmax(0…7)THmin(0) THmin(7)

1

Pmax(0..7)

(a) Default WRED Drop Probability Configuration

Drop Probability

THmax(0…7)THmin(0) THmin(7)

1

Pmax(0)

Pmax(7) Average Queue Length

(b) WRED case 1

Average Queue Length

Drop Probability

THmax(7)THmin(0) THmin(7)

1

Pmax(0)

Pmax(7)

THmax(0)

(c) WRED case 2

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


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

Probabilisticpacket drop

Buffer level (average In_profile)

In-Profile (Green)

Out-Profile (Red)

Buffer level (average_Total)

0Avg_in

Avg_total

Drop Probability

Average Queue Lengthmin_out max_out

1

Pmax_out

Pmin_outPmax_inPmin_in

max_inmin_in


DiffServ Packet Scheduler (1)

Priority-based, Weight-based Packet Scheduler

Priority Scheduler

Priority Scheduler

priority

priority

priority

priority

Rate-basedscheduler(WRR or

WFQ)

Rate-basedscheduler(WRR or

WFQ)

weight

weight

weight

weight

(a) Priority-based Scheduler (b) Weight-based Scheduler

(c) Hierarchical Packet Scheduler


DiffServ Packet Scheduler (2)

Hierarchical Packet Scheduler

Priority Scheduler

Priority Scheduler

Rate-basedscheduler

(WRR or WFQ)

Rate-basedscheduler

(WRR or WFQ)

NCT1

NCT0

EF

AF4

AF3

AF2

AF1

BF

priority

priority

priority

priority

Min rate

Min rate

Min rate

Min rate

shaping rate(PDR/PBS,

CDR/CBS+EBS)

Tra

ffic

Sha

per

Tra

ffic

Sha

per

priority


Traffic Shaping

ClassifyMeasure

Configured rate

Token bucket

No match

Incomingpackets

Queuing method

Outgoing packets

Committedrate

WFQ/FIFO

Pac

ket

Sch

edul

er


Multi-Protocol Label Switching (MPLS)


MPLS (Multi-Protocol Label Switching)

sourceA

destinationB

Ingress Node

Egress Node

IP datagram

IP datagram

label i

label j

label klabel m

MPLS Domain Network


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

Ru

UpstreamLSR

Rd

DownstreamLSR

Packet Label

assign outgoing labelcheck incoming label

label distribution

Bind <label, FEC>

check incoming labelassign outgoing label


Hierarchical Label Stacking

R1R1 R2R2 Rn-1Rn-1 RnRn

LSP ingress (push a label) swapping swapping

LSP egress (pop the label)

RiRi Ri+1Ri+1

LSP ingress (push a label)

LSP egress (pop the label)

Packet Plevel (m-1)

Packet Plevel (m-1)

Packet P level (m+k)

Packet P, level (m)


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


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)


Constraint-Routed LDP (CR-LDP)

connection request fromTE manager

CR-LDP (label request) CR-LDP (label request)CR-LDP (label request)

CR-LDP (label mapping)



O-NIC

IP

TCP/UDP

CR-LDP

NIA(ONIC)

MPLS-LSR(ingress)

O-NIC

IP

TCP/UDP

CR-LDP

NIA(ONIC)

MPLS-LSR(intermediate)

O-NIC

IP

TCP/UDP

CR-LDP

NIA(ONIC)

MPLS-LSR(intermediate)

O-NIC

IP

TCP/UDP

CR-LDP

NIA(ONIC)

MPLS-LSR(egress)

WDM WDM WDM

OSPF-TE/BGP

OAM

OSPF-TE/BGP

OAM

OSPF-TE/BGP

OAM

OSPF-TE/BGP

OAM


CR-LDP Traffic Parameters

Length

Peak Data Rate (PDR)

Peak Burst Size (PBS)

Committed Data Rate (CDR)

Committed Burst Size (CBS)

Excess Burst Size (EBS)

Traf. Param. TLV U F

Reserved Weight Frequency Flags

Flags control “negotiability” of parameters

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

32 bit fields are short IEEE floating point numbers

Any parameter may be used or not used by selecting appropriate values


RSVP-TE

Sender A

Sender B

RouterR1

RouterR1

RouterR2

RouterR2

ReceiverC

ReceiverD

Path

Data

Path

Data

PathData

Path

Data

ResvPath

Data

Resv Resv

Resv

RSVP-TE Message Path, Resv

PathTear, ResvTear

PathErr, ResvErr

ResvConf, Hello, Notify


Traffic Policing for CR-LSP

Three token buckets : Peak Rate, Committed Rate, Excess

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)

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)


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 c

onsidering 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 committe

d rate among CR-LSPs

Packet scheduling for EF (Expedited Forwarding) packet to minimize delay & jitter

optional traffic shaping


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 Fun

ction triggers fault management function & LSP restoration/rerouting


MPLS OAM Packets (Example)

OAM Type OAM Function PDU Length

Ingress LSR Identifier

Egress LSR Identifier

LSP Identifier

Sequence Number

Time Stamp

Number of Total Transmitted Packets

Total Transmitted Data Size [Byte]

Optional Information

10 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 01 2 30

(a) Performance Management OAM

OAM Type OAM Function PDU Length

Loop-back start LSR Identifier

Loop-back end LSR Identifier

LSP Identifier

Loop-back operation mode

Optional data

10 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 01 2 30

(b) Loopback Test OAM


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


Fault Management Flow (Example)

PHY

TCP/UDP

CR-LDP

MPLSIP

OSPF-TE/BGP

TE

Age

nt

LSR 120

PHY

TCP/UDP

CR-LDP

MPLSIP

OSPF-TE/BGP

TE

Age

nt

LSR 121

PHY

TCP/UDP

CR-LDP

MPLSIP

OSPF-TE/BGP

TE

Age

nt

LER 110(ingress node)

PHY

TCP/UDP

CR-LDP

MPLSIP

OSPF-TE/BGP

TE

Age

nt

LSR 220

PHY

TCP/UDP

CR-LDP

MPLSIP

OSPF-TE/BGP

TE

Age

nt

LSR 221

PHY

TCP/UDP

CR-LDP

MPLSIP

OSPF-TE/BGP

TE

Age

nt

LER 211(egress node)

working LSP

backup LSP

link failure detection

link failure notification

TE agentcontrolsthe rerouting


MPLS Fault Management (FM) OAM

LSR120 LSR140

LER110

LER150

LSR130

timeout

timeout

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

(b) Roll-call loop-back test


Constraint-based Shortest Path First (CSPF) Routing

OSPF_TE

- TLV information setup using TLVInfo Object-Construct Opaque LSA Table at LSDatabase Object

MPLS Network Interface Info.

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

(1) TE metric update in each interface

(get-TE-interface())

(2) Opaque LSA information Link State

Information(TLV info DB)

(3) TE Constraints of connection setup

TruncatedLink State Information

(satisfying the constraints)

Dijstra’sShortest Path First

Algorithm


OSPF, CR-LDP and Resource Allocation

Traffic EngineeringManager

(Backbone Trunk LSP Information)

Constraint-based SPF(CSPF)Routing

OSPFLink status information

gathering

Shortest Path Finding(Dijkstra)

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

CR-LDP / RSVP-TESignaling

Traffic EngineeringAgent

(LDP Bandwidth Update)

MPLS LSR or OXC-LSR


DiffServ-aware-MPLS Traffic Engineering


DiffServ-over-MPLS Traffic Engineering

DiffServ IP Packet Flow

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 )

DiffServ-awareMPLS LSR

DiffServ-awareMPLS LSR

Classifier

Meter

Actions (drop)

QueuingP

acke

t Sch

edul

ing

Host

Host

Host

IPRouter

IPRouter

Sha

ping

/M

appi

ng to

LS

P


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 pac

ket’s label value the packet’s drop precedence is conveyed in the EXP field of the MP

LS shim header or in the encapsulating link layer specific selective drop mechanism (ATM, FR, 802.1)


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%”

PhysicalTransmission

Medium(Electrical,

Optical,MicrowaveSatellite)

Maximum reservable

aggregate BW

Allocated BW

Un-reserved BW

cont

roll

ed

traf

fic

CR-LSP(Resource class

= “silver”)


= “bronze”)best

-eff

ort

traf

fic


= “gold”)

for Class-type NCBR real-time

traffic (voice/video)

rt/nrt-VBR traffic(data, Web/HTTP,

FTP, E-mail)

VP

N tr

affi

c

traffic typeService

class

VPN control traffic

DiffServ Classes ina Class-type N

AF1, 2, 3, 4

EF (or AF1)

NCT(11x000)

BE (default)


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

PhysicalTransmission

Medium(Electrical,

Optical,MicrowaveSatellite)

Maximum reservable

aggregate BW

Allocated BW

Un-reserved BW

traffic typeService

UserDiffServ Classes in

a Class-type N

AF1, 2, 3, 4

EF (or AF1)

NCT(11x000)

BE (default)

CBR real-timetraffic (voice/video)


FTP, E-mail)

Cli

ent

A

VPN control traffic

CR-LSPfor Class-type

AF 3x, 4x


EF


BE


NCT


AF 1x


AF 2x

AF1, 2, 3, 4

EF (or AF1)

NCT(11x000)

BE (default)

CBR real-timetraffic (voice/video)


FTP, E-mail)

Cli

ent

B

VPN control traffic


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 E-

LSP)


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-to-end 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.


Example Mapping of EXP and PHB

DSCP Class (DSCP)EXP code

(suggested)Per-Hop-Behavior (suggested)

Best Effort (000 000) 000Default Forwarding with best effort

(highest drop precedence)

AF 1, High Drop Precedence (001 110) 001Assured Forwarding 1, High Drop Precedence

for non-real time bulk data transfer

AF 2, Med Drop Precedence ( 010 100) 010Assured Forwarding 2, Med Drop Precedence

for non-real time ABR

AF 3, Med Drop Precedence ( 011 100) 011Assured Forwarding 3, Med Drop Precedence

for non-real time VBR data

AF 4, Low Drop Precedence (100 010) 100Assured Forwarding 4, Low Drop Precedence

for real-time VBR data

Expedited Forwarding (EF) : (101 110) 101Minimized delay & jitter for Real-time CBR

traffic

Network Control Traffic (110 000)

(User-to-user control traffic)110 Minimized error, high priority

Network Control Traffic (111 000) 111 Minimized error, highest priority


MPLS LSP Stacking and Bandwidth Borrowing

LSP k (weight = z)

LSP i (weight = x)

LSP j (weight = y)

Excess available bandwidth

Tunnel LSPre-allocation of excess bandwidth

in proportion to the weight


Hierarchical Packet Scheduling and Recursive Bandwidth Borrowing

(a) Hierarchy of LSP (b) Hierarchy of packet scheduler

Pac

ket S

ched

Pac

ket S

ched

uler

Pac

ket S

ched

Available Excess Bandwidth

User LSP Inner Tunnel LSP Outer Tunnel LSP

(C) Recursive Bandwidth Borrowing


Fault Restoration in MPLS Network


Protection Switching Types

(b) 1+1 Path Restoration(a) 1:1 Path Restoration

...

working path(N)

backup path

(c) 1:N Path Restoration

...

.. ..

working path(N)

backup path(M)

(d) M:N Path Restoration


Link-, Path-, Span-Restoration

(a) Normal Operation (b) Path Switching/protection

(c ) Span Protection (d) Link/Line Protection


Path Restoration vs. Segment-Restoration

(a) Link Restoration (c) 1+1 Path Restoration(b) 1:1 Path Restoration

(d) Segment Restoration


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

(a) UPSR

ProtectionRing

Working Ring

(b) BLSR

Working& Protection

Working &Protection


Restoration using p-Cycles

A p-cycle

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

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


Shared Risk Link Group (SRLG)

Examples of SRLG id in Optical Link

Conduit(SRLG-1)

bundle (SRLG-2)

link-3 (SRLG-3)

5

6

link-1(SRLG-4)

link-2 (SRLG-5)

1

2

3

4

OXC-1 OXC-2 OXC-3

OXC-4 OXC-5 OXC-6

conduit bundlefiber

Working pathBackup path


Differentiated Fault Restoration Policy

Differentiated Backup Path Reservations (Example)

Backup Path Utilization Reservation with NO Traffic Reservation with Lower Priority Traffic

Allow working path traffic at restoration

MPLS Service

Class

Bandwidth

Reservation (%)

Setup

Priority

Preemption

PriorityApplication

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


DiffServ-aware-MPLS Traffic

Engineering of Cisco Routers


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, rate-shaping, IP precedence, DSCP setting), core QoS feature (WFQ, WRED)


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


Network Management System to support DiffServ-aware-MPLS Traffic Engineering

GIAServiceObject

ServiceObject

ServiceObject

ServiceObject

ServiceclassifierService

classifier

Telnet InterfaceTelnet Interface

Transceiver Transceiver

parserparserConnectivity CheckConnectivity Check

Traffic Monitoring Traffic Monitoring

RMA InterfaceSNMP Interface

SNMP-GetSNMP-Get

SNMP-SetSNMP-Set

CLI Interface

SNMP-GetNextSNMP-GetNext

IIOP

SNMP SOCKETTELNET

(TCP Port 23)

CustomerPremise Network

CPN(Intranet)

DNSCustomerPremise Network

CPN(Intranet)Internet Transit Network

IIOP

ConfigurationMgmt

ConfigurationMgmt

ConnectionMgmt

ConnectionMgmt

PerformanceMgmt

PerformanceMgmt

FaultMgmtFaultMgmt

EMS

ConfigurationMgmt

ConfigurationMgmt

ConnectionMgmt

ConnectionMgmt

PerformanceMgmt

PerformanceMgmt

FaultMgmtFaultMgmt

NMSGUI

OperatorInterface

GUIOperatorInterface



RMA

Traffic Monitoring(Packet Capture)

Traffic Monitoring(Packet Capture)

Connectivity Check(ICMP)

Connectivity Check(ICMP)


Explicit establishment DiffServ-aware-LSP

DiffServ-aware MPLS Network

DiffServ-aware

MPLS LER

MPLSTransitLSR

MPLSTransitLSR

MPLSTransitLSR

DiffServ-aware

MPLS LER

CPNA

CPNB

EMS EMS EMS

NMSConstraint-based

Shortest Path First (CSPF) Routing


Performance measurement of QoS, Transfer Rate and Connectivity checks

(c) IP Connectivity check

(a) Traffic monitoring

(b) Traffic analysis (per Protocol)

Drop rate

0

50000

100000

150000

200000

250000

300000

1 5 9 13

17

21

25

29

33

37

41

45

49

53

57

61

65

69

73

77

81

85

time(sec)

bp

s AFBFEF

transfer rate

0

50000

100000

150000

200000

250000

300000

350000

400000

450000

1 6

11

16

21

26

31

36

41

46

51

56

61

66

71

76

81

86

time(sec)

bps AF

BFEF

(d) Transmission Data rate

(e) Packet Drop rate


Test Networking Configuration

Traffic Trunk LSP1 Mbps

LSP 1-3500 Kbps

LSP 2-4500 Kbps

200Kbps

300Kbps

200Kbps

300Kbps

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

Cisco3620/7204

Cisco7204

Cisco3620/7204

PC 1

PC 2

PC 3

PC 4

(a) Physical topology

(b) Logical topology


Test Results

Test Configuration Flow 1, 3 (200Kbps CBR), rate lim

it= 200 Kbps, Burst size Bc=5Kbyt

es, Be=5Kbytes

Flow 2, 4 (300~500 Kbps VBR), ra

te limit= 300 Kbps, Burst size Bc=

5Kbytes, Be=5Kbytes

MPLS LSP 1-3: Bandwidth=500Kb

ps, Burst Size

MPLS LSP 2-4: Bandwidth= 500K

bps

DiffServ-aware MPLS packet sche

duling

Traffic generation model: fixed pac

ket size

Input Data Rate

0

50

100

150

200

250

300

350

400

450

500

1

10

19

28

37

46

55

64

73

82

91

100

109

118

127

136

145

Time[sec]

Kbps

Flow1Flow2

Received Data Rate

0

50

100

150

200

250

300

350

400

450

500

1 9

17

25

33

41

49

57

65

73

81

89

97

105

113

121

129

137

145

Time[sec]

Kbps

Flow1Flow2


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 traffi

c 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 top

ology

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.


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.


[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.


Thank You !!!

Youngtak Kim, Ph.D., Associate ProfessorDept. of Information and Communication Engineering,

College of Engineering, Yeungnam University

(Tel: +82-53-810-2497, Fax: +82-53-814-5713, E-mail: [email protected])

Documents

DiffServ-aware-MPLS Networking: a Promising Traffic Engineering for Next Generation Internet (NGI)