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DiffServ-aware-MPLS Networking: a Promising Traffic Engineering for Next Generation Internet (NGI). 2002. 9. 25. Youngtak Kim Advanced Networking Technology Lab. ( ANT Lab. ) Dept. of Information & Communication Engineering, YeungNam University, Korea ( [email protected] ). Outline.

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Diffserv aware mpls networking a promising traffic engineering for next generation internet ngi

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

2002. 9. 25.

Youngtak Kim

Advanced Networking Technology Lab. (ANT Lab.)

Dept. of Information & Communication Engineering,

YeungNam University, Korea

([email protected])


Outline

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 next generation internet ngi

Networking Model and Traffic Engineering ofNext Generation Internet (NGI)


Diffserv aware mpls networking a promising traffic engineering for next generation internet ngi

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


Ngi with ip mpls and wdm optical network

IP Layer network

GMPLS/PSC Layer network

IP

Router

IP

Router

GMPLS/OXC layer Network

IP

Router

IP

Router

LSP

IP

Router

IP

Router

IP

Router

GMPLS PSC-LSR

IP

Router

IP

Router

GMPLS OXC-LSR

NGI with IP, MPLS and WDM Optical Network


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

GMPLS-Signaling + OAM/LMP

GMPLS-Signaling for optical network

Application

TCP/UDP

IP

IP

LSP

MPLS

MPLS

OXC

OXC

IP

O-NIC

(WDM)

O-NIC

(WDM)

O-NIC

(WDM)

NIC

O-NIC

(WDM)

O-NIC

(WDM)

O-NIC

(WDM)

fiber

bundle

NIC

PSC-LSR

(Optional Core)

OXC-LSR

(Core)

Host A

IP Router

PSC-LSR

(Edge)

OXC-LSR

(Core)

Inter-networking with GMPLS-based WDM Optical Network


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)

Protocol Layers of Optical Internet


Mpls lsr label switching router

IP Routing Protocol

(RIP, OSPF, BGP)

Control Plane in a node

IP Routing agent

MPLS

OAM

IP Routing Table

OAM message

MPLS Signaling

(CR-LDP, RSVP-TE)

MPLS Signaling agent

IP/Label forwarding table updates

Data Plane in a node

Incoming IP

Packets

Outgoing IP Packets

IP Forwarding (Edge node only)

FEC

Incoming Labeled

Packets

MPLS Label Forwarding

Outgoing Labeled Packets

MPLS LSR (Label Switching Router)


Optical lambda switching and fiber switching

OSPF-TE, BGP

IP Routing Protocols for

control channel setup

Link

Management

Protocol

(LMP)

IP Routing Table

LMP message

GMPLS Signaling Protocol for

Optical Network

(Wavelength allocation, optical path

setup & release)

CR-LDP, RSVP-TE

Control Plane in a node

Link Management

switching table updates

Data Plane in a node

Lambda 0

Lambda 0

port 1

port 1

Lambda / Fiber Switching Table

Lambda 1

Lambda 1

  • Lambda Add-drop

  • Wavelength routing

  • Wavelength translating

  • Fiber switching

• • •

• • •

Lambda N

Lambda N

port 2

port 2

• • •

• • •

port n

port n

Optical Lambda Switching and Fiber Switching


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

Hierarchical Traffic Grooming in GMPLS Network


Traffic engineering

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

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

Response Time

Capacity Planning,

Resource provisioning

Re-configuration of logical topology

(traffic trunk)

Network Load re-balancing

Long term

(weeks, months)

Call/connection admission control

Connection duration

(sec, min, hour)

Call/connection routing

(constraint-based)

Dynamic source coding

Feedback Flow Control

Traffic parameter

adjusting

Round-trip delay

(msec)

Adaptive windows

Adaptive rate control

Explicit Notification

Traffic shaping

Excess traffic marking

Packet Processing

Time (usec)

Traffic policing

Selective discarding

Reactive control

Preventive control

Traffic Control and Management Functions


Itu t i 371 traffic management framework

User-Network Interface

(UNI)

Network A

SB

TB

- CAC

- RM

- PC

- Others

B-TE

B-NT2

B-NT1

UPC

Optional Traffic

Shaping

Inter-Network

(NNI)

Network B

TB

SB

- CAC

- RM

- PC

- Others

NPC

B-TE

B-NT2

B-NT1

ITU-T I.371 Traffic Management Framework

UPC: Usage Parameter Control

CAC: Connection Admission Control

PC: Priority Control

NPC: Network Parameter Control

RM: Resource Management

Others: Spacing, Framing, Shaping, etc


Diffserv aware mpls networking a promising traffic engineering for next generation internet ngi

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

ISP 1

ISP 2

User

A

User

B

GMPLS Network

GMPLS Network

OXC/WDM Optical

Backbone Network

OXC/WDM Optical

Backbone Network

Internet Traffic Engineering with DiffServ and GMPLS


Traffic engineering with diffserv aware mpls

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)


Service level agreement sla

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

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 qos parameters of bearer service among ip routers

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


Closed loop control in traffic engineering

Long-term

optimization

Network Provisioning

Mid-term

optimization

(Re-) configuration of logical topology

(traffic trunk)

Router parameter setting

(Bandwidth allocation, Queuing, packet scheduling)

Real-time per-flow

optimization

DiffServ-aware-MPLS

DiffServ-aware-MPLS

End system

A

End system

B

Collect &

Analysis

Measurement

results

Node performance monitoring

End-to-end performance measurement

Closed-loop Control in Traffic Engineering


Differentiated service diffserv

Differentiated Service (DiffServ)


Differentiated service

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

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)

  • 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


Example of diffserv class type

Example of DiffServ Class-type

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


Differentiated packet processing

Smoothing

(averaging)

Buffer depth

NCT

(Network Control Traffic)

Packet

Scheduling

Traffic Shaping

IP Packet

flow input

Expedited Forwarding (EF)

Metering, Action, Algorithmic Dropping

Packet Classifier

Assured Forwarding (AF)

Packet Transmission

with Link Speed X

(LSP : PDR/PBS,

CDR/CBS+EBS)

Best Effort Forwarding (BEF)

Packet

Discarding

(algorithmic

dropping)

Differentiated Packet Processing


Diffserv traffic handler

Packet

Classification

Scheduling/

shaping

Metering/Marking

Per-Class-Queues

count

drop

?

Single Rate TCM

(CIR/CBS+EBS)

count

drop

?

Single Rate TCM

(CIR/CBS+EBS)

NCT0

NCT1

AF 3

AF 4

AF 2

AF 1

EF

Single Rate TCM

(CIR/CBS+EBS)

count

drop

?

IP Packet

Stream

count

drop

?

Packet Classifier

Priority-based Scheduler

Two Rate TCM

(PIR/PBS, CIR/CBS+EBS)

Two Rate TCM

(PIR/PBS, CIR/CBS+EBS)

Two Rate TCM

(PIR/PBS, CIR/CBS+EBS)

Two Rate TCM

(PIR/PBS, CIR/CBS+EBS)

count

drop

?

Rate-based Scheduler

count

drop

?

count

drop

?

BF

drop

?

count

DiffServ Traffic Handler


Packet classifier and traffic conditioner

Meter

Packets

Marker

Shaper/

Scheduler

Classifier

Packet Classifier and Traffic Conditioner


Traffic policing metering marking and re marking

Traffic Policing, Metering / Marking and Re-marking

(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

Buffer level

0

packet drop

at buffer-full

Drop Probability

1

Queue Length

Buffer Limit

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


Per class type queuing 2 red random early detection queue

Buffer level

TH min

TH max

0

Discard with increasing

probability Pa

Discard

Do not discard

Probabilistic

packet drop

Drop Probability

1

Pmax

Pmin

THmax

THmin

Average Queue Length

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


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)

THmax(0…7)

THmin(7)

(a) Default WRED Drop Probability Configuration

Drop Probability

Drop Probability

1

1

Pmax(0)

Pmax(0)

Pmax(7)

Average

Queue

Length

Pmax(7)

Average

Queue

Length

THmax(0…7)

THmin(0)

THmin(7)

THmin(0)

THmax(0)

THmax(7)

THmin(7)

(b) WRED case 1

(c) WRED case 2

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


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

Probabilistic

packet drop

1

Pmax_out

Pmax_in

Pmin_in

Pmin_out

min_out

min_in

max_out

max_in

Average Queue Length

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


Diffserv packet scheduler 1

priority

weight

Priority

Scheduler

priority

weight

priority

weight

priority

weight

Rate-based

scheduler

(WRR or

WFQ)

DiffServ Packet Scheduler (1)

  • Priority-based, Weight-based Packet Scheduler

(b) Weight-based Scheduler

(a) Priority-based Scheduler

(c) Hierarchical Packet Scheduler


Diffserv packet scheduler 2

NCT1

NCT0

EF

AF4

priority

Priority

Scheduler

priority

AF3

shaping rate

(PDR/PBS,

CDR/CBS+EBS)

priority

AF2

Min rate

Traffic Shaper

Min rate

Rate-based

scheduler

(WRR or WFQ)

priority

AF1

Min rate

Min rate

BF

priority

DiffServ Packet Scheduler (2)

  • Hierarchical Packet Scheduler


Traffic shaping

Committed

rate

Token

bucket

Outgoing packets

WFQ/FIFO

Incoming

packets

Configured rate

Packet

Scheduler

Classify

Measure

No

match

Queuing method

Traffic Shaping


Multi protocol label switching mpls

Multi-Protocol Label Switching (MPLS)


Mpls multi protocol label switching

Ingress Node

label i

IP datagram

label j

source

A

IP datagram

label k

label m

Egress Node

destination

B

MPLS Domain Network

MPLS (Multi-Protocol Label Switching)


Label distribution protocol ldp

Ru

Rd

Downstream

LSR

Upstream

LSR

label distribution

Bind <label, FEC>

Packet

Label

assign outgoing label

assign outgoing label

check incoming label

check incoming label

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


Hierarchical label stacking

Packet P level (m+k)

Packet P, level (m)

Packet P

level (m-1)

Packet P

level (m-1)

LSP ingress (push a label)

LSP egress (pop the label)

swapping

swapping

R1

R2

Rn-1

Rn

     

     

Ri

Ri+1

LSP ingress (push a label)

LSP egress (pop the label)

Hierarchical Label Stacking


Mpls traffic engineering

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

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

OSPF-TE/

BGP

OSPF-TE/

BGP

OSPF-TE/

BGP

OSPF-TE/

BGP

CR-LDP

CR-LDP

CR-LDP

CR-LDP

OAM

OAM

OAM

OAM

TCP/UDP

TCP/UDP

TCP/UDP

TCP/UDP

IP

IP

IP

IP

WDM

WDM

WDM

NIA(ONIC)

NIA(ONIC)

NIA(ONIC)

NIA(ONIC)

O-NIC

O-NIC

O-NIC

O-NIC

MPLS-LSR

(ingress)

MPLS-LSR

(egress)

MPLS-LSR

(intermediate)

MPLS-LSR

(intermediate)

CR-LDP (label request)

CR-LDP (label request)

connection request from

TE manager

CR-LDP (label request)

CR-LDP (label mapping)

CR-LDP (label mapping)

CR-LDP (label mapping)

Constraint-Routed LDP (CR-LDP)


Cr ldp traffic parameters

CR-LDP Traffic Parameters


Rsvp te

Sender A

Receiver

C

Resv

Path

Data

Path

Data

Path

Path

Path

Data

Data

Data

Router

R2

Router

R1

Resv

Resv

Sender B

Receiver

D

Resv

RSVP-TE

  • RSVP-TE Message

    • Path, Resv

    • PathTear, ResvTear

    • PathErr, ResvErr

    • ResvConf, Hello, Notify


Traffic policing for cr lsp

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)


Discarding options of marked packet

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


Mpls oam

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


Mpls oam packets example

1

1

2

2

3

3

0

0

0

0

1

1

2

2

3

3

4

4

5

5

6

6

7

7

8

8

9

9

0

0

1

1

2

2

3

3

4

4

5

5

6

6

7

7

8

8

9

9

0

0

1

1

2

2

3

3

4

4

5

5

6

6

7

7

8

8

9

9

0

0

1

1

OAM Type

OAM Type

OAM Function

OAM Function

PDU Length

PDU Length

Ingress LSR Identifier

Loop-back start LSR Identifier

Loop-back end LSR Identifier

Egress LSR Identifier

LSP Identifier

LSP Identifier

Loop-back operation mode

Sequence Number

Time Stamp

Optional data

Number of Total Transmitted Packets

Total Transmitted Data Size [Byte]

Optional Information

(b) Loopback Test OAM

(a) Performance Management OAM

MPLS OAM Packets (Example)


Ip performance measurements

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

link failure

notification

TE agent

controls

the rerouting

link failure

detection

IP

IP

IP

IP

IP

IP

MPLS

MPLS

MPLS

MPLS

MPLS

MPLS

OSPF-TE/

BGP

OSPF-TE/

BGP

OSPF-TE/

BGP

OSPF-TE/

BGP

OSPF-TE/

BGP

OSPF-TE/

BGP

CR-LDP

CR-LDP

CR-LDP

CR-LDP

CR-LDP

CR-LDP

TCP/UDP

TCP/UDP

TCP/UDP

TCP/UDP

TCP/UDP

TCP/UDP

TE Agent

TE Agent

TE Agent

TE Agent

TE Agent

TE Agent

working LSP

backup LSP

PHY

PHY

PHY

PHY

PHY

PHY

LER 110

(ingress node)

LSR 221

LSR 121

LSR 220

LSR 120

LER 211

(egress node)

Fault Management Flow (Example)


Mpls fault management fm oam

LSR130

LSR120

LSR140

LER

110

LER

150

timeout

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

timeout

(b) Roll-call loop-back test

MPLS Fault Management (FM) OAM


Constraint based shortest path first cspf routing

OSPF_TE

Truncated

Link State

Information

(satisfying the

constraints)

Link State

Information

(TLV info DB)

(2) Opaque LSA

information

  • TLV information setup using

  • TLVInfo Object

  • Construct Opaque LSA Table

  • at LSDatabase Object

(3) TE Constraints of

connection setup

(1) TE metric update in

each interface

(get-TE-interface())

Dijstra’s

Shortest Path First

Algorithm

MPLS Network Interface Info.

  • Interface information Base

  • * Interface Info :

  • * TE Metrics :

Constraint-based Shortest Path First (CSPF) Routing


Ospf cr ldp and resource allocation

MPLS LSR or OXC-LSR

Constraint-based SPF(CSPF)

Routing

Traffic Engineering

Agent

(LDP Bandwidth Update)

Shortest Path Finding

(Dijkstra)

OSPF

Link status information

gathering

CR-LDP / RSVP-TE

Signaling

Resource Management

(Bandwidth allocation,

Wavelength allocation,

Resource status table)

OSPF, CR-LDP and Resource Allocation

Traffic Engineering

Manager

(Backbone Trunk LSP

Information)


Diffserv aware mpls traffic engineering

DiffServ-aware-MPLS Traffic Engineering


Diffserv over mpls traffic engineering

  • DiffServ-aware

  • MPLS 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 )

Host

Host

Host

DiffServ IP

Packet Flow

Classifier

Meter

Shaping /

Mapping to LSP

Packet Scheduling

Actions (drop)

Queuing

IP

Router

DiffServ-over-MPLS Traffic Engineering


Mpls support of diffserv

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)


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%”

DiffServ Classes in

a Class-type N

Service

class

traffic type

BE (default)

CR-LSP

(Resource class

= “gold”)

for Class-type N

rt/nrt-VBR traffic

(data, Web/HTTP,

FTP, E-mail)

AF1, 2, 3, 4

Physical

Transmission

Medium

(Electrical,

Optical,

Microwave

Satellite)

Maximum

reservable

aggregate BW

Allocated BW

Un-reserved BW

VPN traffic

EF (or AF1)

CBR real-time

traffic (voice/video)

NCT(11x000)

CR-LSP

(Resource class

= “silver”)

VPN control traffic

controlled

traffic

CR-LSP

(Resource class

= “bronze”)

best-effort

traffic

E-LSP (Exp-inferred-LSPs) Mapping


L lsp label only inferred lsps mapping

DiffServ Classes in

a Class-type N

Service

User

traffic type

BE (default)

AF1, 2, 3, 4

rt/nrt-VBR traffic

(data, Web/HTTP,

FTP, E-mail)

rt/nrt-VBR traffic

(data, Web/HTTP,

FTP, E-mail)

Physical

Transmission

Medium

(Electrical,

Optical,

Microwave

Satellite)

Maximum

reservable

aggregate BW

Allocated BW

Un-reserved BW

EF (or AF1)

Client B

Client A

CBR real-time

traffic (voice/video)

CBR real-time

traffic (voice/video)

NCT(11x000)

CR-LSP

for Class-type

EF

CR-LSP

for Class-type

AF 3x, 4x

CR-LSP

for Class-type

AF 2x

CR-LSP

for Class-type

AF 1x

VPN control traffic

VPN control traffic

BE (default)

AF1, 2, 3, 4

CR-LSP

for Class-type

NCT

CR-LSP

for Class-type

BE

EF (or AF1)

NCT(11x000)

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


Mapping diffserv class type into e lsp

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

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

Example Mapping of EXP and PHB


Mpls lsp stacking and bandwidth borrowing

re-allocation of excess bandwidth

in proportion to the weight

Tunnel LSP

LSP i (weight = x)

Excess available

bandwidth

LSP j (weight = y)

LSP k (weight = z)

MPLS LSP Stacking and Bandwidth Borrowing


Hierarchical packet scheduling and recursive bandwidth borrowing

Available Excess

Bandwidth

Packet Sched

Packet Scheduler

Packet Sched

User LSP

Inner Tunnel LSP

Outer Tunnel LSP

(a) Hierarchy of LSP

(b) Hierarchy of packet scheduler

Hierarchical Packet Scheduling and Recursive Bandwidth Borrowing

(C) Recursive Bandwidth Borrowing


Fault restoration in mpls network

Fault Restoration in MPLS Network


Protection switching types

(a) 1:1 Path Restoration

(b) 1+1 Path Restoration

working path(N)

working path(N)

...

...

..

..

backup path(M)

backup path

(c) 1:N Path Restoration

(d) M:N Path Restoration

Protection Switching Types


Link path span restoration

Link-, Path-, Span-Restoration

(b) Path Switching/protection

(a) Normal Operation

(d) Link/Line Protection

(c ) Span Protection


Path restoration vs segment restoration

(a) Link Restoration

(b) 1:1 Path Restoration

(c) 1+1 Path Restoration

Path Restoration vs. Segment-Restoration

(d) Segment Restoration


Ring based protection switching algorithms

Working

& Protection

Working &

Protection

Working

Ring

Protection

Ring

(a) UPSR

(b) BLSR

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


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

Restoration using p-Cycles


Shared risk link group srlg

Conduit

(SRLG-1)

link-1

(SRLG-4)

bundle

(SRLG-2)

OXC-1

conduit

OXC-2

OXC-3

bundle

1

2

link-2

(SRLG-5)

fiber

link-3

(SRLG-3)

3

4

5

6

OXC-4

OXC-5

OXC-6

Working path

Backup path

Shared Risk Link Group (SRLG)

  • Examples of SRLG id in Optical Link


Differentiated fault restoration policy

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


Diffserv aware mpls traffic engineering of cisco routers

DiffServ-aware-MPLS Traffic Engineering of Cisco Routers


Diffserv functions in commercial 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 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

NMS

GUI

Operator

Interface

Configuration

Mgmt

Connection

Mgmt

Performance

Mgmt

Fault

Mgmt

IIOP

Service

Object

EMS

Service

Object

GUI

Operator

Interface

Configuration

Mgmt

Connection

Mgmt

Performance

Mgmt

Fault

Mgmt

IIOP

GIA

Service

classifier

CLI Interface

SNMP Interface

RMA Interface

SNMP-Get

Connectivity Check

Telnet Interface

SNMP-GetNext

Traffic Monitoring

SNMP-Set

parser

TELNET

(TCP Port 23)

SNMP

SOCKET

Transceiver

Connectivity Check

(ICMP)

DNS

RMA

Customer

Premise

Network

CPN(Intranet)

Customer

Premise

Network

CPN(Intranet)

Traffic Monitoring

(Packet Capture)

Internet Transit Network

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


Explicit establishment diffserv aware lsp

NMS

EMS

EMS

EMS

DiffServ-aware MPLS Network

DiffServ

-aware

MPLS LER

DiffServ

-aware

MPLS LER

CPN

A

CPN

B

MPLS

Transit

LSR

MPLS

Transit

LSR

MPLS

Transit

LSR

Explicit establishment DiffServ-aware-LSP

Constraint-based

Shortest Path First

(CSPF) Routing


Performance measurement of qos transfer rate and connectivity checks

Performance measurement of QoS, Transfer Rate and Connectivity checks

(a) Traffic monitoring

(d) Transmission Data rate

(b) Traffic analysis (per Protocol)

(e) Packet Drop rate

(c) IP Connectivity check


Test networking configuration

PC

3

PC

1

PC

4

PC

2

Cisco

3620/

7204

Cisco

7204

Cisco

3620/

7204

200Kbps

LSP 1-3

500 Kbps

Flow 1:

PC 1 to PC 3

200 Kbps CBR

Traffic Trunk LSP

1 Mbps

300Kbps

Flow 2:

PC 1 to PC 3

300 ~ 500 Kbps VBR

200Kbps

LSP 2-4

500 Kbps

Flow 3:

PC 2 to PC 4

200 Kbps CBR

300Kbps

Flow 4:

PC 2 to PC 4

300 ~ 500 Kbps VBR

Test Networking Configuration

(a) Physical topology

(b) Logical topology


Test results

Test Results

  • Test Configuration

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

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

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

    • MPLS LSP 2-4: Bandwidth= 500Kbps

    • DiffServ-aware MPLS packet scheduling

    • Traffic generation model: fixed packet size


Concluding remarks

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.


References

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.


Diffserv aware mpls networking a promising traffic engineering for next generation internet ngi

[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.


Diffserv aware mpls networking a promising traffic engineering for next generation internet ngi

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])


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