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Network and Service Interworking in Layer 2 VPNs over MPLS

- By Matthew [email protected]

2

Outline

> Motivation for Converging L2 Services on MPLS> Network and Service Interworking> Expectations on the New Converged Packet Network> Interworking the User Plane> Interworking the Control Plane> Interworking the Management Plane (OAM)> Conclusions> Further Reading

3

Service Convergence over MPLS

> Service providers are introducing new MPLS based packet switchedcore networks

They are introducing Ethernet in the access> Motivations:

Generate new revenues by broadening the range of services delivered from the IP network

Extend the reach of existing Ethernet/FR/ATM services to new sites Interconnect regional ATM networks over a national IP/MPLS network Reduce CAPEX and possibly OPEX Avoid per-service/per-technology networks

4

Standard Service Convergence Solutions

> Based on Layer 2 Network and Service Interworking functions> Network Interworking:

Allows networks to communicate transparently across different link layer technologies

Interworking is performed at the link layer (L2) by encapsulating one link layer in the other

Typically deployed inside the network and is not visible to end-users> Service Interworking:

Allows CPEs to exchange service layer PDU across different link layer technologies

Interworking is performed by terminating the link layers and translating based on knowledge of the payload service context

Constraints visible to end-users

5

Network and Service Interworking Benefits

ATM

ATMMPLS

Ethernet

Ethernet

Ethernet

ATM PW

Ethernet PW

> Network Interworking: OPEX & CAPEX reduction across the combined service portfolio and

consolidated infrastructure Growing existing service revenues

> Service Interworking: Developing new revenue opportunities from a more flexible service offering

e.g. offer an Ethernet access service to customers that already have ATM or FR access to a layer 2 VPN

6

Expectations of the New Converged Packet Network

> Coping with traffic growth in a cost-effective way Enhance utilization of infrastructure

> Carrier class protection and restoration Offer flexible levels of protection (e.g., hot-standby versus warm-standby

backup, local versus end-to-end protection) Provide reactive and pro-active OAM capabilities

> Service level differentiation Offer different services with different performance objectives (e.g., VoIP,

Virtual Leased Lines, Internet access) Offer multiple grades of the same service (e.g., VoIP gold, silver)

> Intelligent edge policy decision Ability to have visibility and to select specific network resources and apply

different policies for routing customer traffic at edge> Maintaining integrity of L2 services

Transparent carriage of existing L2 services Seamless interworking with new services at the user, control , and

management (OAM) planes

7

Basics of Pseudo-Wires

MPLSPE /IWF PE /IWF

Pseudo Wires are the building blocks of a converged packet network

Layer 2AC

Layer 2AC

CE CE

MPLS framepayload

(L2 protocol)

Tunnel LSP

PW Label Inner Label

T-LSP Label Outer Label

MPLS Label Stack

Pseudo-wire

8

Outline

> Motivation for Converging Services on a Common Packet Network

> Network and Service Interworking> Expectations of the New Converged Packet Network> Interworking the User Plane> Interworking the Control Plane> Interworking the Management Plane (OAM)> Conclusions> Further Reading

9

Some L2 VPN Terminology

> An end-to-end virtual circuit in a L2 VPN consists of a 3 segment set:

AC: attachment Circuit; PW: Pseudo-Wire> A L2 VPN circuit is homogeneous if AC and PW types are the same

E.g., ATM circuit:

> A L2 VPN circuit is heterogeneous if any two segments of the circuit are of different type

E.g., IP interworking circuit: , or

10

Types of Interworking over MPLS

> Network Interworking ATM/MPLS using circuits FR/MPLS using circuits Ethernet/MPLS using circuits FR-ATM network interworking (FRF.5) using circuits> Service Interworking

FR-ATM service interworking (FRF.8.2) using circuits

Ethernet interworking using circuits

IP interworking using circuits

11

INE

ATM(PNNI)

ATM 2

ATM UNI

ATM UNI

UNI/NNI

T-LSP

PVC/SPVCATM P

WATM 1

PE 1(ATM-MPLS

Network IWF)

PE 2

MPLS

IP/IPX/SNA

RFC2684B-PDU/R-PDU

AAL5 ATM

PE 3 (ATM-MPLS

Network IWF)

ATM UNI

ATM PW

CE 1

IP/IPX/SNA

RFC2684B-PDU/R-PDU

AAL5 ATM

IP/IPX/SNA

RFC2684B-PDU/R-PDU

ATMoMPLS

MPLS

POS/GigE

CE 2

CE 3

IP/IPX/SNA

RFC2684B-PDU/R-PDU

AAL5 ATM

ATM-MPLS Network Interworking

12

FR-ATM and FR-MPLS Network Interworking over MPLS

INE

ATM(PNNI)

ATM 2

FR UNI

FR UNI

UNI/NNI

T-LSP

PVC/SPVCATM A

AL5 PW

ATM 1 (FR-ATM Network

IWF FRF.5)

PE 1(ATM-MPLS

Network IWF)

PE 2

MPLS

IP/IPX/SNA

RFC2427B-PDU/R-PDU

FR

PE 3 (FR-MPLS

Network IWF)

FR UNI

FR PW

CE 1

IP/IPX/SNA

RFC2684B-PDU/R-PDU

AAL5 ATM

IP/IPX/SNA

RFC2684B-PDU/R-PDU

ATMoMPLS

MPLS

POS/GigE

IP/IPX/SNA

RFC2427B-PDU/R-PDU

FRoMPLS

MPLS

POS/GigE

CE 2

CE 3

IP/IPX/SNA

RFC2427B-PDU/R-PDU

FR

13

FR-ATM Service Interworking over MPLS

PE 2 (ATM-MPLS

Network IWF)

ATM(PNNI)

ATM 2

FR UNI

FR UNI

UNI/NNI

T-LSP

PVC/SPVCATM A

AL5 PW

ATM 1 (FR-ATM Network

IWF FRF.8.1)

PE 1(ATM-MPLS

Network IWF)

MPLS

IP/IPX/SNA

RFC2427B-PDU/R-PDU

FR

PE 3 (FRF.8.1 and

ATM-MPLS Network IWF)

FR UNI

ATM AAL5 PW

CE 1

IP/IPX/SNA

RFC2684B-PDU/R-PDU

AAL5 ATM

IP/IPX/SNA

RFC2684B-PDU/R-PDU

ATMoMPLS

MPLS

POS/GigE

IP/IPX/SNA

RFC2427B-PDU/R-PDU

FRoMPLS

MPLS

POS/GigE

CE 2

CE 3

IP/IPX/SNA

RFC2684B-PDU/R-PDU

AAL5 ATM

14

FR-ATM Service Interworking over MPLS

PE 2 (Ethernet-MPLSNetwork IWF)

ATM(PNNI)

ATM 2

UNI/NNI

T-LSP

PVC/SPVCEthern

et PW

PE 1

MPLS

IP/IPX/SNA

RFC2427B-PDU/R-PDU

FR

PE 3 (Ethernet-MPLSNetwork IWF)

Ethernet(VLAN) UNI

Ethernet PW

CE 1

IP/IPX

RFC2684B-PDU

AAL5 ATM

IP/IPX

Ethernet(VLAN)

EthoMPLS

MPLS

POS/GigE

CE 2

CE 3

IP/IPX

Ethernet(VLAN

Ethernet(VLAN) UNI

ATM 1 (Ethernet-ATMService IWF)

Ethernet(VLAN) UNI

15

IP Interworking over MPLS

ATM(PNNI) MPLS

ATM 2

ATM 4

FR UNI

Ethernet (VLAN) UNI

UNI/NNI

UNI/NNI

T-LSP

FR UNI

T-LSPPVC/SPVC

PVC/SPVC

ATM 1

ATM 3

PE 4

PE 3

PE 1

PE 2

ATM UNI

IP PW

IP PW

IP PW

CE 1

CE 3

> Respond to InvATM ARP (Optional)

> Respond to InvATM ARP (Optional)

CE 4

CE 2

> Ethernet VLAN to IP PW mapping> ARP processing

proxy ARP using local interface MAC

> Ethernet VLAN to IP PW mapping> ARP processing

proxy ARP using local interface MAC

16

End-to-End QoS

> Ingress Classification MFC, DSCP, 802.1p, L2 I/F context (e.g., ATM Service category & CLP) assigned to packet

> Ingress Policing Per L2 CoS policing, e.g., Per VPI/VCI/CLP in a ATM AC

> Queuing and Scheduling in PE Based on assigned

> Admission control in PE Tunnel LSP is assigned bandwidth PW are CACed against tunnel bandwidth

> Egress remarking in PE Configurable mapping of to EXP

> Queuing and Scheduling in Core LSR According to the label value and EXP value for a L-LSP According to the EXP value for a E-LSP

17

AC

Example of QoS Support

MPLSNetwork

PE1

PE2

ATM / Ethernet

ATM / Ethernet

PW on T-LSP

AC

Labels pushed with EXP based on packets QoSLabels pushed with EXP based on packets QoS

Schedule traffic based on label and/or EXP.

Labels popped

Schedule traffic based on label and/or EXP.

Labels popped

Transit LSRs schedule traffic based on label/EXP

Transit LSRs schedule traffic based on label/EXP

18

Outline

> Motivation for Converging Services on a Common Packet Network

> Network and Service Interworking> Expectations of the New Converged Packet Network> Interworking the User Plane> Interworking the Control Plane> Interworking the Management Plane (OAM)> Con

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