The document provides an overview of MPLS (Multi-Protocol Label Switching) concepts and components. It discusses how MPLS separates routing from forwarding by using labels to forward packets based on the label rather than the IP address. It describes MPLS components like edge label switching routers (ELSR or PE), label switching routers (LSR or P), and the label distribution protocol (LDP). It also provides examples of MPLS forwarding and MPLS VPN operation.

1. MPLS Services Kristof De Brouwer

4. MPLS Concepts © 2003 Cisco Systems, Inc. All rights reserved. MPLS Concepts

6. IP Routing 171.69 Packets Forwarded Based on IP Address Data Address Prefix 128.89 171.69 1 1 I/F … Address Prefix 128.89 171.69 0 1 … 0 1 I/F 128.89 0 1 128.89.25.4 Data Address Prefix 128.89 0 … … I/F Data Data 128.89.25.4 128.89.25.4 128.89.25.4 Route Update

8. Label Header Label 1 2 3 4 5 6 7 8 EXP S TTL Bit 2 3 4 1 Byte Label EXP S TTL Label Value (20 bits) Class of Service (3 bits) Bottom of Stack (1 bit) Time to Live

9. Label Encapsulation PPP Ethernet Frame Relay Label IP header Label Label IP Header IP Header Data ATM Header Label Data ATM Header Packet over SONET/SDH Ethernet Frame Relay PVC ATM PVC’s Subsequent cells Data Data Data IP Header FRAME

11. MPLS Components © 2003 Cisco Systems, Inc. All rights reserved.

13. MPLS Components LSR LSR LSR LSR ELSR ELSR P Network (Provider Control) PE CE CE PE ELSR ELSR C Network (Customer Control) C Network (Customer Control) P

16. Control and Forward Plane Separation MPLS Process Route Updates/ Adjacency Label Bind Updates/ Adjacency IP Traffic MPLS Traffic Control Plane Data Plane LFIB Routing Process RIB LIB FIB

17. MPLS: Forwarding

18. MPLS: Forwarding Existing routing protocols (e.g. OSPF, IGRP) establish routes

19. MPLS: Forwarding Label Distribution Protocol (e.g., LDP) establishes label to routes mappings

20. MPLS: Forwarding Label Distribution Protocol (e.g., LDP) creates LFIB entries on LSRs IN OUT I/F MAC Null - E0/0 aa-00-bb Null - E0/1 aa-00-cc IN OUT I/F MAC 16 32 S0/0 aa-00-bb 18 27 S0/0 aa-00-cc IN OUT I/F MAC 32 64 S0/0 aa-00-bb 27 18 S0/1 aa-00-cc IN OUT I/F MAC 64 POP S0/0 aa-00-bb 65 POP S0/1 aa-00-cc

21. MPLS: Forwarding Ingress edge LSR receives packet, performs Layer 3 value-added services, and “label” packets IN OUT I/F MAC Null - E0/0 aa-00-bb Null - E0/1 aa-00-cc IN OUT I/F MAC 16 32 S0/0 aa-00-bb 18 27 S0/0 aa-00-cc IN OUT I/F MAC 32 64 S0/0 aa-00-bb 27 18 S0/1 aa-00-cc IN OUT I/F MAC 64 POP S0/0 aa-00-bb 65 POP S0/1 aa-00-cc

22. MPLS: Forwarding LSRs forward labelled packets using label swapping IN OUT I/F MAC Null - E0/0 aa-00-bb Null - E0/1 aa-00-cc IN OUT I/F MAC 16 32 S0/0 aa-00-bb 18 27 S0/0 aa-00-cc IN OUT I/F MAC 32 64 S0/0 aa-00-bb 27 18 S0/1 aa-00-cc IN OUT I/F MAC 64 POP S0/0 aa-00-bb 65 POP S0/1 aa-00-cc

23. MPLS: Forwarding Edge LSR at egress removes remaining label * and delivers packet * Pentulimate hop popping actually occurs. There may may not necessarily be a label in the packet at the ultimate or egress LSR. IN OUT I/F MAC Null - E0/0 aa-00-bb Null - E0/1 aa-00-cc IN OUT I/F MAC 16 32 S0/0 aa-00-bb 18 27 S0/0 aa-00-cc IN OUT I/F MAC 32 64 S0/0 aa-00-bb 27 18 S0/1 aa-00-cc IN OUT I/F MAC 64 POP S0/0 aa-00-bb 65 POP S0/1 aa-00-cc

24. MPLS MPLS VPN

25. Virtual Networks Virtual Private Networks Virtual Dialup Networks Virtual LANs Overlay VPN Peer-to-Peer VPN Layer-2 VPN Layer-3 VPN Access lists (Shared router) Split routing (Dedicated router) MPLS/VPN X.25 F/R ATM GRE IPSec Virtual Network Models

45. MPLS VPN Operation P P PE PE PE CE CE CE CE PE RR RR MP-BGP between PE router to distribute routes between VPNs IGP (OSPF,ISIS) used to establish reachability to destination networks. Label Distribution Protocol establishes mappings to IGP addresses CE-PE dynamic routing (or static) populate the VRF routing tables Customer routes placed into separate VRF tables at each PE = RT? = RT? Import routes into VRF if route-targets match (export = import) RD + RD + RD + RD + RD + VPN labels, RTs VPN labels, RTs

46. MPLS VPN Forwarding Example PE P P PE CE CE PE PE CE CE Push VPN Label (Red Route) Push IGP Label (Green PE Router) Swap IGP Label (From LFIB) POP IGP Label (Pentultimate Hop) Pop VPN Label (Red Route)

47. MPLS MPLS Service Provider Example

49. Customer Edge interface Loopback0 ip address 7.0.0.1 255.255.255.255 no ip directed-broadcast interface Ethernet0/0 bandwidth 50000 ip address 192.168.0.1 255.255.255.252 no ip directed-broadcast delay 1 ! interface Ethernet1/0 bandwidth 10000 ip address 192.168.0.5 255.255.255.252 no ip directed-broadcast delay 100 ! ! router eigrp 100 network 7.0.0.0 network 192.168.0.0 eigrp stub connected no auto-summary

50. Provider Edge 1 ip vrf cisco_1 rd 100:1 route-target export 100:1 route-target import 100:1 ! interface Ethernet0/0 bandwidth 50000 ip vrf forwarding cisco_1 ip address 192.168.0.2 255.255.255.252 no ip directed-broadcast delay 1 ! router eigrp 10 network 7.0.0.0 network 10.0.0.0 no auto-summary ! router eigrp 100 ! address-family ipv4 vrf cisco_1 redistribute bgp 65001 metric 100000 100 255 255 1500 network 192.168.0.0 no auto-summary autonomous-system 100 eigrp log-neighbor-changes exit-address-family !

51. Provider Edge 1 router bgp 65001 bgp log-neighbor-changes bgp confederation identifier 65003 neighbor 7.0.0.4 remote-as 65001 neighbor 7.0.0.4 update-source Loopback0 ! address-family ipv4 redistribute eigrp 100 neighbor 7.0.0.4 activate neighbor 7.0.0.4 next-hop-self neighbor 7.0.0.4 send-community extended default-metric 10000 no auto-summary no synchronization exit-address-family ! address-family vpnv4 neighbor 7.0.0.4 activate neighbor 7.0.0.4 next-hop-self neighbor 7.0.0.4 send-community extended exit-address-family ! address-family ipv4 vrf cisco_1 redistribute eigrp 100 maximum-paths ibgp 2 no auto-summary no synchronization exit-address-family

52. Provider Edge 2 ip vrf cisco_2 rd 100:2 route-target export 100:1 route-target import 100:1 ! interface Ethernet0/0 bandwidth 10000 ip vrf forwarding cisco_2 ip address 192.168.0.6 255.255.255.252 no ip directed-broadcast delay 100 ! interface Ethernet1/0 ip address 10.0.0.5 255.255.255.252 no ip directed-broadcast tag-switching ip ! router eigrp 10 network 7.0.0.0 network 10.0.0.0 no auto-summary !

53. Provider Edge 2 router eigrp 100 ! address-family ipv4 vrf cisco_2 redistribute bgp 65001 metric 100000 100 255 255 1500 network 192.168.0.0 no auto-summary autonomous-system 100 eigrp log-neighbor-changes exit-address-family ! router bgp 65001 no synchronization bgp log-neighbor-changes bgp confederation identifier 65003 neighbor 7.0.0.4 remote-as 65001 neighbor 7.0.0.4 update-source Loopback0 neighbor 7.0.0.4 next-hop-self neighbor 7.0.0.4 send-community both no auto-summary ! address-family vpnv4 neighbor 7.0.0.4 activate neighbor 7.0.0.4 next-hop-self neighbor 7.0.0.4 send-community both exit-address-family ! address-family ipv4 vrf cisco_2 redistribute eigrp 100 maximum-paths ibgp 2 no auto-summary no synchronization exit-address-family

54. Provider router bgp 65001 no bgp default route-target filter bgp log-neighbor-changes bgp confederation identifier 65003 bgp confederation peers 1 65002 neighbor iBGP peer-group neighbor iBGP remote-as 65001 neighbor iBGP update-source Loopback0 neighbor 7.0.0.2 peer-group iBGP neighbor 10.0.0.34 remote-as 65002 ! address-family ipv4 neighbor iBGP activate neighbor iBGP route-reflector-client neighbor iBGP send-community both neighbor 7.0.0.2 peer-group iBGP neighbor 7.0.0.3 peer-group iBGP neighbor 7.0.0.5 peer-group iBGP neighbor 7.0.0.6 peer-group iBGP neighbor 10.0.0.34 activate no auto-summary no synchronization exit-address-family ! address-family vpnv4 neighbor iBGP activate neighbor iBGP route-reflector-client neighbor iBGP send-community both neighbor 7.0.0.2 peer-group iBGP neighbor 7.0.0.3 peer-group iBGP neighbor 7.0.0.5 peer-group iBGP neighbor 7.0.0.6 peer-group iBGP neighbor 10.0.0.34 activate neighbor 10.0.0.34 send-community extended exit-address-family

55. MPLS Enterprise

63. Q & A