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1 © 2004 Cisco Systems, Inc. All rights reserved. RST-2602 9908_06_2004_X2 DEPLOYING MPLS-VPN SESSION RST-2602 Rajiv Asati

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Presentation on theme: "1 © 2004 Cisco Systems, Inc. All rights reserved. RST-2602 9908_06_2004_X2 DEPLOYING MPLS-VPN SESSION RST-2602 Rajiv Asati"— Presentation transcript:

1 1 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 DEPLOYING MPLS-VPN SESSION RST-2602 Rajiv Asati

2 222 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 Agenda MPLS VPN Definition? Technology Configuration MPLS-VPN Services Providing load-shared traffic to the multihomed VPN sites Providing Hub&Spoke service to the VPN customers Providing MPLS VPN Extranet service Providing Internet access service to VPN customers Providing VRF-selection based services Providing Remote Access MPLS VPN Providing VRF-aware NAT services Advanced MPLS VPN Topics Inter-AS MPLS-VPN CsC Carrier Supporting Carrier Best Practices Conclusion.

3 333 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 Prerequisites Must understand basic IP routing, especially BGP Must understand MPLS basics (push, pop, swap, label stacking) Must finish the evaluation

4 444 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 Terminology: LSR: Label Switch Router LSP: Label Switched Path The chain of labels that are swapped at each hop to get from one LSR to another VRF: VPN Routing and Forwarding Mechanism in IOS used to build per-interface RIB and FIB MP-BGP: Multi-Protocol BGP PE : Provider Edge router Interfaces with CE routers P : Provider (core) router, without knowledge of VPN VPNv4: Address family used in BGP to carry MPLS-VPN routes RD: Route Distinguisher Distinguish same network/mask prefix in different VRFs RT: Route Target Extended Community attribute used to control import and export policies of VPN routes LFIB: Label Forwarding Information Base FIB: Forwarding Information Base (FIB)

5 555 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 Agenda MPLS VPN Definition? Technology Configuration MPLS-VPN Services Providing load-shared traffic to the multihomed VPN sites Providing Hub&Spoke service to the VPN customers Providing MPLS VPN Extranet service Providing Internet access service to VPN customers Providing VRF-selection based services Providing Remote Access MPLS VPN Providing VRF-aware NAT services Advanced MPLS VPN Topics Inter-AS MPLS-VPN CsC Carrier Supporting Carrier Best Practices Conclusion.

6 666 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 MPLS-VPN Operation’s Theory VPN definition: VRF instance VPN Route Propagation (Control Plane) VPN Packet forwarding (Data Plane)

7 777 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 MPLS VPN Connection Model PE VPN Backbone IGP MP-iBGP session PE P P P P PE routers Edge Routers Use MPLS with P routers Uses IP with CE routers Connects to both CE and P routers. Distribute VPN information through MP-BGP to other PE router with VPN-IPv4 addresses, Extended Community, Label P Routers P routers are in the core of the MPLS cloud P routers do not need to run BGP and doesn’t need to have any VPN knowledge Forward packets by looking at labels P and PE routers share a common IGP

8 888 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 MPLS VPN: Separate Routing Tables in PE The Global routing table Populated by the MPLS backbone IGP In PE routers may contain the BGP Internet routes (standard ipv4 routes) CE PE CE EBGP,OSPF, RIPv2,Static vpn site 1 vpn site 2 MPLS Backbone IGP (OSPF, ISIS) VRF routing table Routing (RIB) and Forwarding table (CEF) associated with one or more directly connected sites (CEs) The routes the PE receives from CE Routers are installed in the appropriate VRF routing table(s) blue VRF routing table or green VRF routing table

9 999 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 VRF: Virtual Routing and Forwarding Instance What’s a VRF ? Associates to one or more interfaces on PE Privatize an interface i.e. coloring of the interface Has its own routing table and forwarding table (CEF) VRF has its own instance for the routing protocol (static,RIP,BGP,EIGRP,OSPF) CE router runs standard routing software CE PE CE EBGP,OSPF, RIPv2,Static vpn site 1 vpn site 2 MPLS Backbone IGP (OSPF, ISIS) VRF blue VRF green

10 10 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 CE PE CE EBGP,OSPF, RIPv2,Static vpn site 1 vpn site 2 MPLS Backbone IGP (OSPF, ISIS) VRF: Virtual Routing and Forwarding Instance PE installs the routes, learned from CE routers, in the appropriate VRF routing table(s) PE installs the IGP (backbone) routes in the global routing table VPN customers can use overlapping IP addresses.

11 11 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 Additions in BGP: MPLS-VPN Info BGP RD: Route Distinguisher VPNv4 routes RT: Route Target Label 8 Bytes Route-Target 3 Bytes Label MP-iBGP update with RD, RT, and Label 1:1 8 Bytes 4 Bytes RD IPv4 VPNv

12 12 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 MPLS VPN Control Plane MP-BGP Update Components: VPNv4 address To convert an IPv4 address into a VPNv4 address, RD is appended to the IPv4 address i.e 1:1: Makes the customer’s IPv4 route globally unique. Each VRF must be configured with an RD at the PE RD is what that defines the VRF 8 Bytes Route-Target 3 Bytes Label MP-IBGP update with RD, RT, and Label 1:1 8 Bytes 4 Bytes RD IPv4 VPNv ! ip vrf v1 rd 1:1 !

13 13 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 MPLS VPN Control Plane MP-BGP Update Components: Route-Target Route-target (RT): Identifies the VRF for the received VPNv4 prefix. It is an 8-byte extended Community (a BGP attribute) Each VRF is configured with RT(s) at the PE RT helps to color the prefix 8 Bytes Route-Target 3 Bytes Label MP-IBGP update with RD, RT, and Label 1:1 8 Bytes 4 Bytes RD IPv4 VPNv :2 ! ip vrf v1 route-target import 1:1 route-target export 1:2 !

14 14 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 MPLS VPN Control Plane MP-BGP Update Components: Label The Label (for the VPNv4 prefix) is assigned only by the PE whose address is the Next-Hop attribute PE routers re-write the Next-Hop with their own address (loopback) “Next-Hop-Self” towards MP-iBGP neighbors by default PE addresses used as BGP Next-Hop must be uniquely known in the backbone IGP DO NOT summarize the PE loopback addresses in the core 8 Bytes Route-Target 3 Bytes Label MP-IBGP update with RD, RT, and Label 1:1 8 Bytes 4 Bytes RD IPv4 VPNv :2 50

15 15 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 MPLS VPN Control Plane: Putting It All Together /24 Next-Hop=CE-1 MP-iBGP update: RD: Next-hop=PE-1 RT=Green, Label= /24 PE1PE2 P P P P CE2 CE1 MPLS Backbone Site 1 Site 2 1) PE1 receives an IPv4 update (eBGP,OSPF,EIGRP) 2) PE1 translates it into VPNv4 address Assigns an RT per VRF configuration Re-writes Next-Hop attribute to itself Assigns a label based on VRF and/or interface 3) PE1 sends MP-iBGP UPDATE to other PE routers

16 16 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X /24 Next-Hop=CE-1 MP-iBGP update: RD: Next-hop=PE-1 RT=Green, Label= /24 PE1PE2 P P P P CE2 CE1 MPLS Backbone Site 1 Site /24 Next-Hop=PE-2 4) PE2 receives and checks whether the RT=green is locally configured within any VRF, if yes, then 5) PE2 translates VPNv4 prefix back into IPv4 prefix, Installs the prefix into the VRF Routing table Updates the VRF CEF table with label=100 for /24 Advertise this IPv4 prefix to CE2 (EBGP, OSPF, EIGRP) MPLS VPN Control Plane: Putting It All Together

17 17 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X /24 PE1PE2 P2 P P P1 CE2 CE1 Site 1 Site 2 Global routing/forwarding table Dest->Next-Hop PE2  P1, label: 50 Global routing/forwarding table Dest->NextHop PE1  P2, label: 25 VRF Green forwarding Table Dest->NextHop /24-  PE1, label: 100 e VRF Forwarding table (show ip cef vrf ) PE routers store VPN routes Associated labels Labels distributed through MP-BGP The Global Forwarding table (show ip cef) PE routers store IGP routes Associated labels Label distributed through LDP/TDP MPLS VPN Forwarding Plane:

18 18 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 PE2 imposes TWO labels for each packet going to the VPN destination The top label is LDP learned and Derived from an IGP route Represents LSP to PE address (exit point of a VPN route) The second label is learned via MP-BGP Corresponds to the VPN address /24 PE1PE2 CE2 CE1 Site 1 Site 2 e MPLS VPN Forwarding Plane: P P P P

19 19 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 Agenda MPLS VPN Definition? Technology Configuration MPLS-VPN Services Providing load-shared traffic to the multihomed VPN sites Providing Hub&Spoke service to the VPN customers Providing MPLS VPN Extranet service Providing Internet access service to VPN customers Providing VRF-selection based services Providing Remote Access MPLS VPN Providing VRF-aware NAT services Advanced MPLS VPN Topics Inter-AS MPLS-VPN CsC Carrier Supporting Carrier Best Practices Conclusion.

20 20 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 MPLS VPN Sample Configuration ip vrf VPN-A rd 1:1 route-target export 100:1 route-target import 100:1 Interface Serial0 ip address ip vrf forwarding VPN-A VRF Definition PE-P Configuration P PE1 s1 Interface Serial1 ip address mpls ip router ospf 1 network area /24 PE1 CE1 Site Se0 PE1

21 21 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 MPLS VPN Sample Configuration router bgp 1 neighbor remote-as 1 neighbor update-source loopback 0 address-family vpnv4 neighbor activate neighbor send-community both PE: MP-IBGP RR: MP-IBGP router bgp 1 no bgp default route-target filter neighbor remote-as 1 neighbor update-source loopback0 address-family vpnv4 neighbor route-reflector-client Neighbor activate PE1PE2 RR PE1PE2 RR PE1 RR

22 22 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 MPLS VPN Sample Configuration router bgp 1 ! address-family ipv4 vrf VPN-A neighbor remote-as 2 neighbor activate exit-address-family ! PE-CE BGP PE-CE OSPF router ospf 1 ! router ospf 2 vrf VPN-A network area 0 ! /24 PE1 CE1 Site /24 PE1 CE1 Site PE1

23 23 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 MPLS VPN Sample Configuration router rip address-family ipv4 vrf VPN-A version 2 no auto-summary network exit-address-family PE-CE RIP PE-CE EIGRP router eigrp 1 address-family ipv4 vrf VPN-A network autonomous-system 1 exit-address-family /24 PE1 CE1 Site /24 PE1 CE1 Site

24 24 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 MPLS VPN Sample Configuration ip route vrf VPN-A PE-CE Static PE-CE MB-iBGP routes to VPN router rip address-family ipv4 vrf VPN-A version 2 redistribute bgp 1 metric 1 no auto-summary network exit-address-family /24 PE1 CE1 Site If PE-CE protocol is non BGP then redistribution of other sites VPN routes from MP-IBGP is required. PE1 RR CE1 Site 1

25 25 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 MPLS VPN Sample Configuration router bgp 1 neighbor remote-as 1 neighbor update-source loopback 0 address-family ipv4 vrf VPN-A redistribute {rip|connected|static|eigrp|ospf} PE-RR (VPN routes to VPNv4) PE1 RR CE1 Site 1 If PE-CE protocol is non BGP then redistribution of other sites VPN routes into MP-IBGP is required.

26 26 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 Agenda MPLS VPN Definition? Technology Configuration MPLS-VPN Services Providing load-shared traffic to the multihomed VPN sites Providing Hub&Spoke service to the VPN customers Providing MPLS VPN Extranet service Providing Internet access service to VPN customers Providing VRF-selection based services Providing Remote Access MPLS VPN Providing VRF-aware NAT services Advanced MPLS VPN Topics Inter-AS MPLS-VPN CsC Carrier Supporting Carrier Best Practices Conclusion.

27 27 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 MPLS VPN Services: 1. Loadsharing for the VPN traffic VPN sites (such as Site A) could be multihomed VPN customer may demand the traffic to the multihomed sites be loadshared PE11 PE2 MPLS Backbone PE12 CE1 Site A /24 Site B CE2 RR Route Advertisement

28 28 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 MPLS VPN Services: 1. Loadsharing for the VPN traffic: Cases PE11 PE2 MPLS Backbone PE12 CE1 Site A /24 Site B CE2 RR Traffic Flow RR PE11 PE2 MPLS Backbone PE12 CE1 Site A /24 Site B CE2 Traffic Flow 1 CE  2 PEs 2 CEs  2 PEs

29 29 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 MPLS VPN Services: 1. Loadsharing for the VPN Traffic: Deployment How to deploy the loadsharing ? 1.Configure different VRFs i.e RDs for multihomed site/interfaces. 2.Enable BGP multipath within the relevant BGP VRF address- family at Remote/Receiving PE2. PE11 PE2 MPLS Backbone PE12 CE1 Site A /24 Site B CE2 RR ip vrf green rd 300:11 route-target both 1:1 ip vrf green rd 300:12 route-target both 1:1 router bgp 1 address-family ipv4 vrf green maximum-paths eibgp ip vrf green rd 300:13 route-target both 1:1 1

30 30 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 MPLS VPN Services: 1. Loadsharing for the VPN Traffic (实验) RR must advertise all the paths learned via PE11 and PE12 to the remote PE routers With different RD per VRF, RR does the Best path calculation per RD and advertise them to remote PE Watch out for the increased (~20%) memory consumption (within BGP) due to multipaths at the PEs “eiBGP multipath” implicitly provides eBGP and iBGP multipath for VPN paths PE11 PE2 MPLS Backbone PE12 CE1 Site A /24 Site B CE2 RR Route Advertisement

31 31 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 MPLS-VPN Services: 2. Hub & Spoke Service to the VPN Customers Traditionally, VPN deployments are Hub&Spoke. Spoke to spoke communication is via Hub site only. Despite MPLS VPN’s implicit any-to-any i.e full- mesh connectivity, Hub&Spoke service can easily be offered. Done with import and export of Route-Target (RT).

32 32 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 MPLS-VPN Services: 2. Hub & Spoke Service - Configuration PE-SA PE-Hub MPLS VPN Backbone PE-SB CE-SA CE-SB Spoke B Spoke A / /24 Eth0/0.2 Eth0/0.1 ip vrf green-spoke1 description VRF for SPOKE A rd 300:111 route-target export 1:1 route-target import 2:2 ip vrf green-spoke2 description VRF for SPOKE B rd 300:112 route-target export 1:1 route-target import 2:2 ip vrf HUB-OUT description VRF for traffic from HUB rd 300:11 route-target import 1:1 ip vrf HUB-IN description VRF for traffic to HUB rd 300:12 route-target export 2:2

33 33 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 MPLS-VPN Services: 2. Hub & Spoke Service – Control Plane PE-SA MPLS Backbone PE-SB CE-SA CE-SB Spoke B Spoke A VRF HUB-IN VRF HUB-OUT VRF HUB-OUT RT and LFIB Destination NextHop Label /24 PE-SA /24 PE-SB / /24 All traffic between spokes must pass through the Hub/Central Site. Hub Site could offer FireWall, NAT like applications. Two VRF solution at the PE-Hub: VRF HUB_OUT would have knowledge of every spoke routes. VRF HUB_IN only have Default Route and advertise that to Spoke PEs. Import and export Route-Target within a VRF must be different. PE-Hub VRF HUB-IN Routing Table Destination NextHop CE-H1 Adv Label 35 Route-Target 2:2 Adv /24 Label 50 Route-Target 1:1 Adv /24 Label 40 Route-Target 1:1 VRF RT and LFIB at PE-SA PE-Hub /24 CE-SA VRF RT and LFIB at PE-SB PE-Hub /24 CE-SB

34 34 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 PE-SA PE-Hub MPLS Backbone PE-SB CE-SA CE-SB Spoke B Spoke A VRF HUB-IN VRF HUB-OUT / / LH LA MPLS-VPN Services( 实验内容 ): 2. Hub & Spoke Service – Forwarding Plane

35 35 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 MPLS-VPN Services 3. Extranet VPN MPLS VPN, by default, isolates one VPN customer from another. Separate Virtual Routing Table for each VPN customer Communication between VPNs may be required i.e. Extranet. External Inter-company communication (dealers with manufacturer, Retailer with wholesale provider etc) Management VPN, Shared-service VPN etc. Needs right import and export route-target (RT) values configuration within the VRFs export-map or import-map should be used

36 36 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 3. MPLS-VPN Services : Extranet VPN Goal: Only VPN_A site#1 to be reachable to VPN_B /16 PE1PE2 MPLS Backbone VPN_A Site#2 so P VPN_A Site#1 VPN_B Site# /16 ip vrf VPN_A rd 3000:111 export map VPN_A_Export import map VPN_A_Import route-target import 3000:111 route-target export 3000:111 route-target import 3000:1 ! route-map VPN_A_Export permit 10 match ip address 1 set extcommunity rt 3000:2 ! route-map VPN_A_Import permit 10 match ip address 2 ! access-list 1 permit access-list 2 permit ip vrf VPN_B rd 3000:222 export map VPN_B_Export import map VPN_B_Import route-target import 3000:222 route-target export 3000:222 route-target import 3000:2 ! route-map VPN_B_Export permit 10 match ip address 2 set extcommunity rt 3000:1 ! route-map VPN_B_Import permit 10 match ip address 1 ! access-list 1 permit access-list 2 permit /16 Only Site#1 of both VPNs will communicate to each other, Site#2 won’t.

37 37 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 MPLS-VPN Services 4. Internet Access Service to VPN Customers Could be provided as another value-added service. Security mechanism must be in place at both provider network and customer network To protect from the Internet vulnerabilities VPN customers benefit from the single point of contact for both Intranet and Internet connectivity

38 38 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 MPLS-VPN Services 4. Internet Access: Different Methods of Service Four ways to provide the Internet service 1.VRF Specific default route with “global” keyword 2.Separate PE-CE sub-interface (nonVRF) 3.Extranet with Internet-VRF 4.VRF-aware NAT

39 39 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 MPLS-VPN Services (实验内容) 4. Internet Access: Different Methods of Service 1.VRF Specific default route 1.1 Static default route to move traffic from VRF to Internet (global routing table) 1.2 Static routes for VPN customers to move traffic from Internet (global routing table) to VRF 2.Separate PE-CE sub-interface (non VRF) May run BGP to propagate Internet routes between PE and CE 3.Extranet with Internet-VRF VPN packets never leave VRF context ; issue with Overlapping VPN address 4.Extranet with Internet-VRF along with VRF-aware NAT VPN packets never leave VRF context; works well with overlapping VPN address

40 40 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 A default route, pointing to the ASBR, is installed into the site VRF at each PE A single label is used for packets forwarded according to the default route The label is the IGP label corresponding to the IP address of the ASBR known via the IGP The static route, pointing to the VRF interface, is installed in the global routing table and redistributed into BGP /16 PE1 ASBR CE1 MPLS Backbone Internet GW so P ip vrf VPN-A rd 100:1 route-target both 100:1 Interface Serial0 ip address ip vrf forwarding VPN-A Router bgp 100 no bgp default ipv4-unicast redistribute static neighbor remote 100 neighbor activate neighbor next-hop-self neighbor update-source loopback0 ip route vrf VPN-A global ip route Serial0 Site MPLS-VPN Services: 4.1 Internet access: VRF Specific Default Route (Config) Internet

41 41 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X /16 PE1 PE2 MPLS Backbone so P VRF Routing/FIB Table Destination Label/interface / (global) Site-1 Serial 0 Global Routing/FIB Table Destination Label/Interface /32 Label= /16 Serial 0 IP packet D=Cisco.com Label = 30 IP packet D=Cisco.com IP packet D= Label = 35 IP packet D= Global Table and LFIB Destination Label/Interface /32 Label= / Internet Serial IP packet D= Pros Different Internet gateways can be used for different VRFs PE routers need not to hold the Internet table Simple Configuration Cons Using default route for Internet routing does NOT allow any other default route for intrA_VPN routing Increasing size of global routing Table by leaking VPN routes. Static configuration Site1 so MPLS-VPN Services: 4.1 Internet access: VRF Specific Default Route ( Forwarding) Internet

42 42 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 MPLS-VPN Services 4.2 Internet Access 1.VRF Specific default route 1.1 Static default route to move traffic from VRF to Internet (global routing table) 1.2 Static routes for VPN customers to move traffic from Internet (global routing table) to VRF 2.Separate PE-CE sub-interface (non VRF) May run BGP to propagate Internet routes between PE and CE 3.Extranet with Internet-VRF VPN packets never leave VRF context ; Overlapping VPN addresses could be a problem 4.Extranet with Internet-VRF alongwith VRF-aware NAT VPN packets never leave VRF context; works well with overlapping VPN addresses

43 43 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 ip vrf VPN-A rd 100:1 route-target both 100:1 Interface Serial0.1 ip vrf forwarding VPN-A ip address frame-relay interface-dlci 100 ! Interface Serial0.2 ip address frame-relay interface-dlci 200 ! Router bgp 100 no bgp default ipv4-unicast [snip]… neighbor remote Internet Access Service to VPN Customers Using Separate Sub-Interface (Config) /16 PE1ASBR CE1 MPLS Backbone Internet GW S0.2 P BGP-4 Site S0.1  One sub-interface for VPN routing associated to a VRF  Another sub-interface for Internet routing associated to the global routing table.  Could advertise full Internet Routes or a default route to CE.  The PE will need to advertise VPN routes to the Internet (via global routing table) Internet

44 44 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X /16 PE1PE2 MPLS Backbone PE-Internet GW S0.2 P Site S0.1 IP packet D=Cisco.com CE routing table VPN routes Serial0.1 Internet routes Serial0.2 PE Global Table and FIB Internet routes Label=30 Label = 30 IP packet D=Cisco.com IP packet D=cisco.com Pros CE could dual home and perform optimal routing. Traffic separation done by CE. Cons PE to hold full Internet routes. BGP complexities introduced in CE. Internet Access Service to VPN Customers 4.2 Using Separate Sub-Interface (Forwarding) Internet

45 45 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 Internet Access Service 4.3 Extranet with Internet-VRF The internet routes could be placed within the VRF at the Internet-GW i.e. ASBR VRFs for customers could ‘extranet’ with the internet VRF and receive either default, partial or full internet routes Be careful if duplicating the internet routes in each VRF Works well when the VPN customers don’t have overlapping addresses

46 46 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 Internet Access Service 4.4 Internet Access using VRF-aware NAT If the VPN customers need Internet access without internet routes, then VRF-aware NAT can be used at the Internet-GW i.e. ASBR The Internet GW doesn’t need to have internet routes either Overlapping VPN addresses is not a problem More in the “VRF-aware NAT” slides,…..

47 47 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 MPLS VPN Service 5. VRF-Selection The common notion is that the VRF must be associated to an interface “VRF-selection” breaks this association and associate multiple VRFs to an interface Each packet on the PE-CE interface could be handled (based on certain criteria) via different VRF routing tables Criteria such as source/dest IP address, ToS, TCP port etc. specified via route-map Voice and Data can be separated out into different VRFs at the PE

48 48 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 MPLS VPN Service 5. VRF-Selection – Based on Source IP Address PE1 PE2 MPLS Backbone (Cable Company) CE1 RR /16 VPN Green /16 VPN Blue /16 VPN Brown Global Interface Se0/0 Cable Setup VRF Interfaces Traffic Flows ip vrf brown rd 3000:111 route-target export 3000:1 route-target import 3000:1 ! ip vrf blue rd 3000:222 route-target export 3000:2 route-target import 3000:2 ! ip vrf green rd 3000:333 route-target export 3000:3 route-target import 3000:3 route-map PBR-VRF-Selection permit 10 match ip address 40 set vrf brown route-map PBR-VRF-Selection permit 20 match ip address 50 set vrf blue route-map PBR-VRF-Selection permit 30 match ip address 60 set vrf green interface Serial0/0 ip address ip policy route-map PBR-VRF-Selection ip receive brown ip receive blue ip receive green access-list 40 permit access-list 50 permit access-list 60 permit

49 49 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 MPLS VPN Service 6. Remote Access Service Remote access users i.e. dial users, IPSec users could directly be terminated in VRF PPP users can be terminated into VRFs IPSec tunnels can be terminated into VRFs Remote Access services integration with MPLS VPN opens up new opportunities for Providers

50 50 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 Internet MPLS VPN Service 6. Remote Access Service– IPSec to MPLS VPN Internet Corporate Intranet Branch Office Access Remote Users/ Telecommuters MPLS VPN IPSec Session IP Cable/DSL/ ISDN ISP IP/MPLS/Layer 2 Based Network VPN A VPN B SP Shared Network Customer B Customer A head office Customer C PE VPN C SOHO Local or Direct Dial ISP Cisco IOS VPN Routers or Cisco Client 3.x or higher Customer A branch office PE SP AAA Customer AAA PE+IPSec Aggregator VPN A

51 51 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 MPLS-VPN Services 7. VRF-Aware NAT Services VPN customers could be using ‘overlapping’ IP address i.e /8 Such VPN customers must NAT their traffic before using either “extranet” or “internet” or any shared* services PE is capable of NATting the VPN packets (eliminating the need for an extra NAT device) * VoIP, Hosted Content, Management etc/

52 52 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 MPLS-VPN Services 7. VRF-Aware NAT Services Typically, inside interface(s) connect to private address space and outside interface connect to global address space NAT occurs after routing for traffic from inside-to-outside interfaces NAT occurs before routing for traffic from outside-to-inside interfaces Each NAT entry is associated with the VRF Works on VPN packets in the following switch paths : IP->IP, IP->MPLS and MPLS->IP

53 53 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 Internet MPLS-VPN Services: 7. VRF-Aware NAT Services – Internet Access PE11 PE-ASBR MPLS Backbone PE12 CE1 Blue VPN Site /24 P CE /24 Green VPN Site ip nat inside ip nat outside VRF-aware NAT Specific ConfigVRF specific Config ip nat pool pool-green prefix-length 24 ip nat pool pool-blue prefix-length 24 ip nat inside source list vpn-to-nat pool pool-green vrf green ip nat inside source list vpn-to-nat pool pool-blue vrf blue ip access-list standard vpn-to-nat permit ip route vrf green global ip route vrf blue global ip vrf green rd 3000:111 route-target both 3000:1 ip vrf blue rd 3000:222 route-target both 3000:2 router bgp 3000 address-family ipv4 vrf green network address-family ipv4 vrf blue network

54 54 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 MPLS-VPN Services: 7. VRF-Aware NAT Services – Internet Access This is also one of the ways to provide Internet access to VPN customers with or without overlapping addresses PE11 PE-ASBR MPLS Backbone PE12 CE1 Blue VPN Site /24 P CE2 Traffic Flows /24 Green VPN Site Src= Dest=Internet Src= Dest=Internet Src= Dest=Internet Src= Dest=Internet Label=30 Src= Dest=Internet Label=40 Src= Dest=Internet IP Packet MPLS Packet IP Packet NAT Table VRF IP SourceGlobal IPVRF-table-id green blue PE-ASBR removes the label from the received MPLS packets per LFIB Performs NAT on the resulting IP packets Forwards the packet Internet

55 55 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 Agenda MPLS VPN Definition? Technology Configuration MPLS-VPN Services Providing load-shared traffic to the multihomed VPN sites Providing Hub&Spoke service to the VPN customers Providing MPLS VPN Extranet service Providing Internet access service to VPN customers Providing VRF-selection based services Providing Remote Access MPLS VPN Providing VRF-aware NAT services Advanced MPLS VPN Topics Inter-AS MPLS-VPN CsC Carrier Supporting Carrier Best Practices Conclusion.

56 56 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 What Is Inter-AS? VPN-A PE-1 PE2 CE2 CE-1 AS #1 AS # /24 MP-iBGP update:: BGP, OSPF, RIPv /24,NH=CE-1 Problem: How do Provider X and Provider Y exchange VPN routes ? ??? ASBR1 ASBR2 RR2 RR1 Provider X Provider Y

57 57 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 Inter-AS Deployment Scenarios VPN-A PE1 VPN-A PE2 CE2 1. Back-to-back VRFs 2. MP-eBGP for VPNv4 3. Multihop MP-eBGP between RRs 4. Non-VPN Transit Provider Following options/Scenarios for deploying Inter-AS : AS #1 AS #2 ASBR1 ASBR2 CE1 2 and 3 are more common and will be discussed. 1 and 4 are in backup slides.

58 58 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 Scenario 2: MP-eBGP between ASBRs to Exchange VPNv4 Routes New CLI “no bgp default route-target filter” is needed on the ASBRs. ASBRs exchange VPN routes using eBGP (VPNv4 af) ASBRs store all VPN routes – But only in BGP table and LFIB table Not in routing nor in CEF table ASBRs don’t need - VRFs to be configured on them LDP between them

59 59 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 Scenario 2: MP-eBGP bet ASBRs for VPNv4 Control Plane (实验内容) PE-1 PE-2 VPN-B CE-2 CE-3 VPN-B ASBR-1 ASBR /24 BGP, OSPF, RIPv /24, NH=CE-2 MP-iBGP update: RD:1:27: /24, NH=PE-1 RT=1:1, Label=(40) MP-iBGP update: RD:1:27: /24, NH=ASBR-2 RT=1:1, Label=(30) BGP, OSPF, RIPv /24, NH=PE-2 MP-eBGP update: RD:1:27: /24, NH=ASBR-1 RT=1:1, Label=(20)

60 60 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 Scenario 2: MP-eBGP bet ASBRs for VPNv4 Forwarding Plane PE-1 PE-2 VPN-B CE-2 CE-3 VPN-B ASBR-1 ASBR / P1 P2 MPLS Packets between ASBRs More scalable. Only one interface between ASBRs routers No VRF configuration on ASBR. Less memory consumption (no RIB/FIB memory) MPLS label switching between providers Still simple, more scalable & works today ProsCons Automatic Route Filtering must be disabled But we can apply BGP filtering. ASBRs are still required to hold VPN routes

61 61 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 Cisco IOS Configuration Scenario 2: External MP-BGP between ASBRs for VPNv4 ( 实验内容) VPN-A PE1 VPN-A PE2 CE-2 CE-1 ASBR1 ASBR2 AS #1 AS #2 MP-eBGP for VPNv4 Label exchange between ASBRs using MP-eBGP /30 Note: ASBR must already have MP- iBGP session with iBGP neighbors such as RRs or PEs. Router bgp x no bgp default route-target filter neighbor x remote-as x ! address-family vpnv4 neighbor x activate neighbor x send-com extended ASBR MB-EBGP Configuration

62 62 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 Scenario 3: Multihop MP-eBGP between RRs to exchange VPNv4 routes Exchange VPNv4 prefixes via the Route Reflectors Requires Multihop MP-eBGP (with next-hop-unchanged) Exchange IPv4 routes with labels between directly connected ASBRs using eBGP Only PE loopback addresses need to be exchanged (they are BGP next-hop addresses of the VPN routes)

63 63 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 Scenario 3: Multihop MP-eBGP between RRs for VPN routes : Control Plane PE-1 PE-2 VPN-B CE-2 CE-3 VPN-B ASBR-1 RR-2 AS#2 ASBR-2 RR-1 IP-v4 update: Network=PE-1 NH=ASBR-1 Label=(20) BGP, OSPF, RIPv /24,NH=CE /24 VPN-v4 update: RD:1:27: /24, NH=PE-1 RT=1:1, Label=(90) BGP, OSPF, RIPv /24,NH=PE-2 AS#1 IGP+LDP: Network=PE-1 NH=ASBR-2 Label=(30) IGP+LDP: Network=PE-1 NH=PE-1 Label=(40) Note - Instead of IGP+Label, iBGP+Label can be used to exchange PE routes/label. Please see Scenario#5 on slide#49 and 50.

64 64 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 Scenario 3: Multihop MP-eBGP between RRs for VPN routes : Forwarding Plane PE-1 PE-2 VPN-B CE-2 CE-3 VPN-B RR-2 ASBR-2 RR / ASBR-1 P1 P2 Note - Instead of IGP+Label, iBGP+Label can be used to exchange PE routes/label.

65 65 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 Scenario 3: Pros/Cons Pros Cons More scalable than Scenario 1 and 2. Separation of control and forwarding planes Route Reflector exchange VPNv4 routes+labels RR hold the VPNv4 information anyway ASBRs now exchange only IPv4 routes+labels ASBR Forwards MPLS packets Advertising PE addresses to another AS may not be acceptable to few providers.

66 66 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 Cisco IOS Configuration Scenario 3: Multihop MP-eBGP between RRs for VPNv4 (实 验) VPN-A PE1 VPN-A PE2 CE-2 CE-1 ASBR-1 RR-2 AS #1 AS #2 Multihop MP-eBGP for VPNv4 with next-hop-unchange ASBR-2 RR-1 eBGP IPv4 + Labels iBGPipv4+label could also be used in within each AS (instead of “network ”) to propagate the label information for PEs. router ospf x redistribute bgp 1 subnets ! router bgp x neighbor remote-as x ! address-family ipv4 Network mask neighbor activate neighbor send-label router bgp x neighbor remote-as x neighbor ebgp-multihop neighbor update loopback 0 ! address-family vpnv4 neighbor activate neighbor send-com extended neighbor next-hop-unchanged RR Configuration ASBR Configuration

67 67 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 Inter-AS Deployment Guidelines 1.Use ASN in the Route-target i.e. ASN:xxxx 2.Max-prefix limit (both BGP and VRF) on PEs 3.Security (BGP MD5, BGP filtering, BGP max-prefix etc) on ASBRs 4.End-to-end QoS agreement on ASBRs 5.Route-Target rewrite on ASBR 6.Internet connectivity on the same ASBR ??

68 68 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 Agenda MPLS VPN Definition? Technology Configuration MPLS-VPN Services Providing load-shared traffic to the multihomed VPN sites Providing Hub&Spoke service to the VPN customers Providing MPLS VPN Extranet service Providing Internet access service to VPN customers Providing VRF-selection based services Providing Remote Access MPLS VPN Providing VRF-aware NAT services Advanced MPLS VPN Topics Inter-AS MPLS-VPN CsC Carrier Supporting Carrier Best Practices Conclusion.

69 69 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 Carrier Supporting Carriers: CsC Benefits of CsC What do I need to do to enable CsC ? Deployment models Security in CsC Deployment Guideline Deployment Scenarios

70 70 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 MPLS/VPN Networks without CsC Unwanted routing updates in the Carrier’s network => CPU+memory Label/prefix consumptions at PE => memory Scalability issue at PE Large Number of VPN Routes at the PE May Pose Limitation to the PE

71 71 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 MPLS/VPN Networks without CsC The no of VPN routes is one of the biggest limiting factor in scaling the PE router Few SPs are running into this scalaing limitation If no of VPN routes can be reduced somehow (without loosing the functionality), then the existing investment can be protected The same PE can still be used to connect more VPN customers Carrier Supporting Carrier (CsC) provides the mechanism to reduce the no of routes from each VRF by enabling MPLS on the PE-CE link

72 72 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 Benefits of CsC Provide transport for ISPs ($) No need to manage external routes from ISPs Build MPLS Internet Exchange (MPLS-IX) ($$) Media Independence; POS/FDDI/PPP possible Higher speed such OC192 or more Operational benefits Sell VPN service to subsidiary companies that provide VPN service ($)

73 73 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 What Do I Need to Enable CsC ? 1.Build an MPLS-VPN enabled carrier’s network 2.Connect ISP/SPs sites (or PoPs) to the Carrier’s PEs 3.Exchange internal routes + labels between Carrier’s PE & ISP/SP’s CE 4.Exchange external routes directly between ISP/SP’s sites

74 74 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 CsC Deployment Models PE1 PE2 ISP PoP Site-1 CE-1 CE-2 IPv4 routes with label distribution ISP PoP Site-2 MP-iBGP for VPNv4 Carrier’s MPLS Core P1 ASBR-2 R1 R2 ISP customers = external routes Full-mesh iBGP for external routes IPv4 routes with label distribution ASBR-1 internal routes = IGP routes Internal routes = IGP routes IGP+LDP INTERNET C1 MPLS enabled VRF int

75 75 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 CsC Deployment Models 1.Customer-ISP not running MPLS 2.Customer-ISP running MPLS 3.Customer-ISP running MPLS-VPN Model 1 and 2 are less common deployments. Model 3 will be discussed in detail.

76 76 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 PE1 PE2 ISP PoP Site-1 CE-1 CE /32, NH=CE-1, Label = /32, NH=PE-2, Label = 52 ISP PoP Site-2 MP-iBGP update: 1:1: /32, RT=1:1 NH =PE-1, Label=51 Carrier’s Core P1 ASBR_PE /32 ASBR_PE-2 R1 R2 Network = /24 MP-iBGP update: 1:1: /24, RT=1:1 NH = /32, Label = 90 IGP+LDP, Net=PE-1, Label = pop IGP+LDP, Net=PE-1, Label = 16 VPN Site /24, NH=R /24, NH =ASBR_PE-2 IGP+LDP /32,Label = pop IGP+LDP, /32 NH=CE-2, Label=60 IGP+LDP, /32 NH=C1, Label=70 VPN Site-1 C1 CsC: ISP Sites Are Running MPLS-VPN Hierarchical MPLS-VPN Control Plane

77 77 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 PE1 PE2 ISP PoP Site-1 CE-1 CE-2 ISP PoP Site-2 Carrier’s Core P1 ASBR-1ASBR-2 R1R2 Network = / VPN Site-1VPN Site-2 C1 CsC: ISP Sites Are Running MPLS-VPN Hierarchical MPLS-VPN Forwarding Plane

78 78 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 Security Mechanism in CsC BGP/LDP MD5 on PE-CE To prevent label “spoofing”, PE Maintains Label VRF table association Checks during LFIB lookup that received packet’s label is what was allocated If the check fails, then the packet is dropped.

79 79 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 CsC Deployment Guideline Two choices for deploying CsC 1.IGP+LDP on the PE-CE, or 2.eBGP ipv4 +label on the PE-CE (RFC3107) Choice selection is driven by the choice of routing protocol on the PE-CE CE has to run MPLS-aware code

80 80 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 CsC: IOS Commands/Configs Choice 1: What All You Need to Configure? Sh mpls interface [vrf ] all  Sh mpls ldp disc [vrf ] all  Sh mpls ldp bind vrf  Sh mpls ip bind vrf  Sh mpls ldp neighbor [vrf ] all  Sh mpls forward [vrf ] int ser0/0 ip vrf forwarding green mpls ip mpls ldp protcol ldp int ser0/0 mpls ip mpls ldp protcol ldp  Sh mpls interface  Sh mpls ldp discovery  Sh mpls ldp bind  Sh mpls ldp neighbor  Sh mpls forward Choice1: Enable LDP on PE-CE; PE-1 CE-1 VRF Int IGP+LDP PE1 CE1

81 81 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 CsC: IOS Commands/Configs Choice 2: What All You Need to Configure? router bgp 1 address-family ip vrf green neighbor remote-as 2 neighbor send-label router bgp 2 neighbor remote-as 1 neighbor send-label Choice2: Enable eBGP+label on PE-CE; PE-1 CE-1 eBGP+label VRF Int 1. No IGP needed on PE-CE 2. No LDP needed on PE-CE PE1 CE1

82 82 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 IOS Commands/Configs Choice 2: eBGP+label on the PE-CE On PE Sh ip bgp vpn vrf neighbor Sh ip bgp vpn vrf label Sh mpls forward vrf On CE Sh ip bgp neighbor Sh ip bgp labels Sh mpls forward

83 83 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 Agenda MPLS VPN Definition? Technology Configuration MPLS-VPN Services Providing load-shared traffic to the multihomed VPN sites Providing Hub&Spoke service to the VPN customers Providing MPLS VPN Extranet service Providing Internet access service to VPN customers Providing VRF-selection based services Providing Remote Access MPLS VPN Providing VRF-aware NAT services Advanced MPLS VPN Topics Inter-AS MPLS-VPN CsC Carrier Supporting Carrier Best Practices Conclusion.

84 84 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 Best Practices 1.Use RR to scale BGP. 2.Deploy RRs in pair for the redundancy 3.Keep RRs out of the forwarding paths and disable CEF (saves memory). 4.Consider Unique RD per VRF per PE, if Load sharing of VPN traffic is reqd. 5.RT and RD should have ASN in them i.e. ASN : X Reserve first few 100s of X for the internal purposes such as filtering 6.Don't use customer names as the VRF names; Nightmare for the NOC. Use simple combination of numbers and characters in the VRF name For example - v101, v102, v201, v202 etc. Use description. 7.Define an upper limit at the PE on the # of prefixes received from the CE for each VRF or neighbor max-prefix within the VRF configuration max-prefix per neighbor within the BGP VRF af (if BGP on the PE-CE)

85 85 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 Conclusion MPLS VPN is a cheaper alternative to traditional l2vpn MPLS-VPN paves the way for new revenue streams VPN customers could outsource their layer3 to the provider Straightforward to configure any-to-any VPN topology partial-mesh, hub&spoke topologies can also be easily deployed CsC and Inter-AS could be used to expand into new markets VRF-aware services could be deployed to maximize the investment

86 86 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 Complete Your Online Session Evaluation! WHAT:Complete an online session evaluation and your name will be entered into a daily drawing WHY:Win fabulous prizes! Give us your feedback! WHERE:Go to the Internet stations located throughout the Convention Center HOW:Winners will be posted on the onsite Networkers Website; four winners per day

87 87 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 Thanks for your time. Q & A Eval -

88 88 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2

89 89 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 BACK UP SLIDES

90 90 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 Scenario 1: Back-to-back VRF Control Plane PE-1 PE-2 VPN-B CE-2 CE-3 VPN-B VRF to VRF Connectivity between ASBRs ASBR-1 ASBR /24 BGP, OSPF, RIPv /24,NH=CE-2 VPN-v4 update: RD:1:27: /24 NH=PE-1 RT=1:1, Label=(29) VPN-B VRF Import routes with route-target 1:1 BGP, OSPF, RIPv /24 NH=ASBR-2 VPN-v4 update: RD:1:27: /24, NH=ASBR-2 RT=1:1, Label=(92) VPN-B VRF Import routes with route-target 1:1 BGP, OSPF, RIPv /24,NH=PE-2

91 91 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 Not scalable. #of interface on both ASBRs is directly proportional to #VRF. No end-to-end MPLS. Unnecessary memory consumed in RIB/(L)FIB Dual-homing of ASBR makes provisioning worse Scenario 1: Back-to-back VRF Forwarding Plane PE-1 PE-2 VPN-B CE-2 CE-3 VPN-B ASBR-1 ASBR / P2 P IP Packets between ASBRs Per-customer QoS is possible It is simple and elegant since no need to load the Inter-AS code (but still not widely deployed). ProsCons

92 92 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 Cisco IOS Configuration Scenario 1: Back-to-Back VRF between ASBRs AS #1 AS #2 VRF routes exchange via any routing protocol Note: ASBR must already have MP- iBGP session with iBGP neighbors such as RRs or PEs /30 ip vrf green rd 1:1 route-target both 1:1 ! Router bgp x Address-family ipv4 vrf green neighbor x activate ASBR VRF and BGP config VPN-A PE1 CE-1 VPN-A CE-2 PE2 ASBR1 ASBR2

93 93 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 VPN-A PE1 VPN-A PE2 CE-2 CE-1 ASBR1 ASBR2 AS #1 AS #2 Multi-Hop MP-eBGP for VPNv4 IGP & LDP interface serial 0 ip address x/30 mpls ldp protcol ldp router bgp x no bgp default route-target filter neighbor remote-as x neighbor update loopback0 neighbor ebgp-multihop ! address-family vpnv4 neighbor activate neighbor send-comm extended Multi-Hop MP-BGP session between ASBRs so IOS Configuration Scenario 2.5: Multi-Hop MP-eBGP for VPNv4

94 94 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 Scenario 4: Non-VPN Transit Provider Two MPLS VPN providers may exchange routes via one or more transit providers Which may be non-VPN transit backbones just running MPLS Multihop MP-eBGP deployed between edge providers With the exchange of BGP next-hops via the transit provider

95 95 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 Option 4: Non-VPN Transit Provider PE1 PE2 VPN-B CE-2 CE-3 VPN-B ASBR-1 RR-2 Non-VPN MPLS Transit Backbone Multihop MP-eBGP OR MP-iBGP for VPNv4 ASBR-2 RR-1 ASBR-3 ASBR-4 next-hop-unchanged eBGP IPv4 + Labels MPLS VPN Provider #1 MPLS VPN Provider #2 iBGP IPv4 + Labels

96 96 © 2004 Cisco Systems, Inc. All rights reserved. RST _06_2004_X2 Route-Target rewrite at ASBR ASBR can add/delete route-target associated with a VPNv4 prefix Secures the VPN environment ASBR(conf)#router bgp 1000 ASBR(conf-router)#neighbor route-map route-target-deletion out ASBR(conf-router)#exit ASBR(conf)#route-map route-target-delete ASBR(conf-route-map)#match extcommunity 101 ASBR(conf-route-map)#set extcomm-list 101 delete ASBR(conf-route-map)#set extcommunity rt 123:123 additive ASBR(conf)# ip extcommunity-list 101 permit rt 100:100


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