V1.1 VPLS Principle

Objectives Understand the basics of mpls layer 2 VPN Understand VPLS principle

Contents Basic Conception Of MPLS Layer 2 VPN VPLS Overview VPLS PE Functions VPLS Working Process

BGP MPLS/VPN feature Establish tunnel on public network by LDP (Label distribution protocol) Implement the following by using MBGP detection and transmission of VPN route Distribute inner layer label to implement address multiplexing Implement route policy by using the extend attribute RT of BGP

Advantage of layer 3 MPLS VPN Customer Outsource WAN infrastructure Transfer the route complexity to provider Suitable for middle or small sized company which do not want to gain core route capability in the company Provider Do not need to maintain the route information among all the core network routers Value added service （ chance to gain profit ）

Disadvantages of layer 3 MPLS VPN Control based on policy adds burden to provider Extensibility and management maybe problem to super network Some customer hope to control their route hierarchy

Layer 2 MPLS VPN Suitable for the access of big company Features ： Regard the access network as a huge switch Establish tunnel by using MPLS label Do layer 2 switch in the whole network

Advantage of layer 2 MPLS VPN Customer Easy to implement on the current layer 2 structure Can maintain control of the route Support any layer 3 routing protocol Provider No extensibility problem due to storing too many customer VPN routes Comparably simple than layer 3 MPLS VPN that use a lot of policy control

L2 MPLS VPN classification VPWS ： Virtual Private Wire Service point to point connection VPLS ： Virtual Private LAN Service point to multipoint connection

Contents Basic Conception Of MPLS Layer 2 VPN VPLS Overview VPLS PE Functions VPLS Working Process

Ethernet develop problem Widely used LAN technology Develop goal is to provide multipoint to multipoint Ethernet service without the limitation of geography space Construct large scale Ethernet by switches Instability of STP Broadcast storm Limited numbers of VLAN

Function of VPLS By using Ethernet and MPLS to satisfy the need of Carrier and customer,enabling the communication between customer’s networks in different place VPWS only provide point to point connection, but VPLS provide point to multipoint connection Carrier’s backbone network

VPLS working principle Establish LSP between PEs Green user and red user are in independent VPN Establish point to point layer 2 VC LSP in LSP tunnel CE can be switch or router Any upper layer protocol MPLS backbone network is like a LAN switch with high reliability and flexibility

VPLS standards VPLS standard is not decided yet, the widely used are: Martini draft Rather mature ， and widely supported by manufactures Support multiple protocols Suitable to be used within AS Need to be configured manually Kompella draft Use the same encapsulation as MARTINI Can be configured automatically Can be used between AS Only support IP protocol

VFI—Distinguish VPN user VFI （ Virtual forwarding Instance ） create a VPLS instance on PE ， different VPLS instances that have the same vc-id on different PE belong to one VPLS and can communicate with each other Carrier’s backbone network PE1 CE3 CE2 PE2 Vfi vpls_a Vcid=100 Peer=PE2 Int fei_1/1 Vfi vpls_a Vcid=100 Peer=PE1 Int fei_1/1 fei_1/2 Fei_1/1 Fei_1/2 CE1

VPLS PE router structure PE include PW management and VPLS instance PW management is responsible for establishing and maintaining the PW with other instances on different PE VFI implement MAC learning and MAC switching. VPLS PE PW management VPLS instance

Contents Basic Conception Of MPLS Layer 2 VPN VPLS Overview VPLS PE Functions VPLS Working Process

VPLS working process—— establishing PW (Pseudo Wire) establishing of PW is to exchange inner label or VC label which identifies VPLS between PE Martini draft make some extensions to LDP, add VC FEC type （ 128 type and 129 type ） Carrier’s backbone network VPN1 VPN2 VPN1 LSP Assign virtual link label by LDP

Service Provider MPLS Backbone Learn MAC address by broadcast PE1 VPLS -B PE2 PE3 MAC XXX MAC ZZZ -A MAC YYY Port 1 VPLS MAC Address LocationPort 100XXXLocalPort 1

PE1 VPLS -B Service Provider MPLS Backbone VPLS PE2 PE3 MAC ZZZ -A MAC YYY Port 1 MAC XXX Learn MAC address by broadcast VPLS MAC Address LocationPort 100XXXLocalPort 1 VPLS MAC Address LocationPort 100XXXRemotePort 1 VPLS MAC Address LocationPort 100XXXRemotePort 1

PE1 VPLS -B Service Provider MPLS Backbone VPLS PE2 PE3 MAC XXX MAC ZZZ -A MAC YYY Port 1 Learn MAC address by Unicast VPLS MAC Address LocationPort 100XXXLocalPort 1 VPLS MAC Address LocationPort 100XXXRemotePort 1 100zzzLocalPort VPLS MAC Address LocationPort 100XXXRemotePort 1

PE1 VPLS -B Service Provider MPLS Backbone VPLS PE2 PE3 MAC XXX MAC ZZZ -A MAC YYY Port 1 Learn MAC address by Unicast VPLS MAC Address LocationPort 100XXXLocalPort 1 100ZZZRemotePort1/LSP VPLS MAC Address LocationPort 100XXXRemotePort 1 100ZZZLocalPort VPLS MAC Address LocationPort 100XXXRemotePort 1

PE1 VPLS -B Service Provider MPLS Backbone VPLS PE2 PE3 MAC XXX MAC ZZZ -A MAC YYY Port 1 Learn MAC address by Unicast VPLS MAC Address LocationPort 100XXXLocalPort 1 100ZZZRemotePort1/LSP VPLS MAC Address LocationPort 100XXXRemotePort 1 100ZZZLocalPort VPLS MAC Address LocationPort 100XXXRemotePort 1 100YYYLocalPort1

PE1 VPLS -B Service Provider MPLS Backbone VPLS PE2 PE3 MAC XXX MAC ZZZ -A MAC YYY Port 1 Learn MAC address by Unicast VPLS MAC Address LocationPort 100XXXLocalPort 1 100ZZZRemotePort1/LSP 100YYYRemotePort1/LSP VPLS MAC Address LocationPort 100XXXRemotePort 1 100ZZZLocalPort VPLS MAC Address LocationPort 100XXXRemotePort 1 100YYYLocalPort1

VPLS loop problem——Horizon split Virtual forwarding instance on PE is like a layer 2 switch, but it doesn’t need to run STP like traditional L2 switch because MPLS L2 VPN use internal horizon split mechanism to avoid loop.

Contents Basic Conception Of MPLS Layer 2 VPN VPLS Overview VPLS PE Functions VPLS Working Process

VPLS working process—create inner label Set VFI on PE ， same VPLS has same vc-id in VFI Set interface on PE as layer 2 transparant transfer port Establish session to assign virtual link label by using extend LDP CE1 PE1PPE2 CE2 Fei_1/2 Fei_1/1Fei_3/2 Fei_3/1 Fei_2/1Fei_2/2 Vfi vpn_a Vcid=100,peer=PE2 Int fei_1/1 PE1: vcid=100 label:16 PE2: vcid=100 label:22 LDP Vfi vpn_a Vcid=100,peer=PE1 Int fei_3/2

VPLS working process—create outside label PE and equipment run routing protocol and establish LSP by using LDP CE1 PE1 P PE2 CE2 Fei_1/2 Fei_1/1Fei_3/2 Fei_3/1 Fei_2/1Fei_2/2 PE1: Lable 3PE2: Lable 3 PE2: Lable 28PE1: Lable 72

VPLS working process—form of label table L2 label table and global label table formed on PE ， global label table formed on P CE1 PE1 P PE2 CE2 Fei_1/2 Fei_1/1Fei_3/2 Fei_3/1 Fei_2/1Fei_2/2 In-int In-label Dest out-label out-int Fei_2/1 28 PE2 pop fei_2/2 Fei_2/2 72 PE1 pop fei_2/1 Dest out-label out-int PE2 28 fei_1/2 In-int vc-id Dest out-label Fei_1/1 100 PE2 22 In-int vc-id Dest out-label Fei_3/2 100 PE1 16 Dest out-label out-int PE1 72 fei_3/1

VPLS working process—data forwarding CE1 wants to communicate with CE2 ， sending ARP PE1 receives this packet ， learn source MAC aaa and record it in VFI CE1 MAC:aaa PE1 P PE2 CE2 MAC:bbb Fei_1/2 Fei_1/1Fei_3/2 Fei_3/1 Fei_2/1Fei_2/2 MAC peer-address outIntLab outExtLab outInt aaa local null null fei_1/1 data S:aaa,D:ffff

VPLS working process—data forwarding PE send to all the VCs according to destination MAC of packet Search L2 label table and global label table to encapsulate packet CE1 MAC:aaa PE1 P PE2 CE2 MAC:bbb Fei_1/2 Fei_1/1Fei_3/2 Fei_3/1 Fei_2/1Fei_2/2 Dest out-label out-int PE2 28 fei_1/2 In-int vc-id Dest out-label Fei_1/1 100 PE2 22 data S:aaa D:ffff data S:aaa,D:ffff

VPLS working process—data forwarding P search label table to forward data and do Penultimate Hop Popping CE1 MAC:aaa PE1 P PE2 CE2 MAC:bbb Fei_1/2 Fei_1/1Fei_3/2 Fei_3/1 Fei_2/1Fei_2/2 data S:aaa D:ffff In-int In-label Dest out-label out-int Fei_2/1 28 PE2 pop fei_2/2 Fei_2/2 72 PE1 pop fei_2/1 data S:aaa D:ffff 22 data S:aaa,D:ffff

VPLS working process—data forwarding PE2 learn source MAC and record it in VFI PE2 send packet to CE2 CE1 MAC:aaa PE1 P PE2 CE2 MAC:bbb Fei_1/2 Fei_1/1Fei_3/2 Fei_3/1 Fei_2/1Fei_2/2 data S:aaa,D:ffff data S:aaa D:ffff data S:aaa D:ffff 22 MAC peer-address outIntLab outExtLab outInt aaa PE fei_3/1 In-int vc-id Dest out-label Fei_3/2 100 PE1 16 Dest out-label out-int PE1 72 fei_3/1 data S:aaa,D:ffff

VPLS working process—data forwarding CE2 send back ARP response to CE1 PE2 learn source MAC and record it in VFI CE1 MAC:aaa PE1 P PE2 CE2 MAC:bbb Fei_1/2 Fei_1/1Fei_3/2 Fei_3/1 Fei_2/1Fei_2/2 MAC peer-address outIntLab outExtLab outInt aaa PE fei_3/1 bbb local null null fei_3/2 data S:bbb,D:aaa

VPLS working process—data forwarding PE2 search and forward packet according to destination MAC CE1 MAC:aaa PE1 P PE2 CE2 MAC:bbb Fei_1/2 Fei_1/1Fei_3/2 Fei_3/1 Fei_2/1Fei_2/2 MAC peer-address outIntLab outExtLab outInt aaa PE fei_3/1 bbb local null null fei_3/2 data S:bbb,D:aaa data S:bbb D:aaa 16 72

VPLS working process—data forwarding PE1 learn source MAC in packet and record it in VFI PE1 search and forward packet according to destination MAC CE1 MAC:aaa PE1 P PE2 CE2 MAC:bbb Fei_1/2 Fei_1/1Fei_3/2 Fei_3/1 Fei_2/1Fei_2/2 data S:bbb,D:aaa data S:bbb D:aaa data S:bbb D:aaa 16 MAC peer-address outIntLab outExtLab outInt aaa local null null fei_1/1 bbb PE fei_1/2 Dest out-label out-int PE2 28 fei_1/2 In-int vc-id Dest out-label Fei_1/1 100 PE2 22 data S:bbb,D:aaa

Review MPLS L2 VPN function VPLS function VFI function MAC address learning process VPLS working process

Question How does VPLS solve the problem of loop ？