Mpls technology


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Mpls technology

  1. 1. MPLSTechnology
  2. 2. Agenda MPLS - The Motivation How MPLS Works ! MPLS Technology MPLS Application Advantages of MPLS Future of MPLS Conclusion Refrences July 29, 2000 TECON 2000 2
  3. 3. MPLS - The Motivation IP Protocol Suite - the most predominant networking technology. Voice & Data convergence on a single network infrastructure. Continual increase in number of users. Demand for higher connection speeds. Increase in traffic volumes. Ever-increasing number of ISP networks. July 29, 2000 TECON 2000 3
  4. 4. What is MPLS? Multi Protocol – supports protocols even other than IP  Supports IPv4, IPv6, IPX, AppleTalk at the network layer  Supports Ethernet, Token Ring, FDDI, ATM, Frame Relay, PPP at the link layer Label – short fixed length identifier to determine a route  Labels are added to the top of the IP packet  Labels are assigned when the packet enters the MPLS domain Switching – forwarding a packet  Packets are forwarded based on the label value  NOT on the basis of IP header information
  5. 5. MPLS BlOCK DIAGRAM ClassificationLSP Label assignment Label swapping Label removalRouting protocol OSPF OSPF OSPFFEC table Local table Local table Local tableAttributes PrecedenceLabel table Local table Local table Local table Layer 2 Layer 2 Layer 2Label Switch Layer 1 Layer 1 Layer 1 Ingress Core Egress Node Node Node July 29, 2000 TECON 2000 5
  6. 6. MPLS Architecture: Control Plane
  7. 7. MPLS Architecture: Data Plane
  8. 8. Basic Model for MPLS Network Existing routing protocols establish routes LDP establishes label to route mappings LDP creates LIB entries for each LSR Ingress LER receives packet,adds a label LSRs forward labeled packets using label swapping Egress LER removes the label and delivers the packet Internet LER LER IP LSR LSR LSR LSR MPLS LER IPLSR = Label SwitchedRouterLER = Label Edge Router
  9. 9. MPLS FORWORDING PROCESS LER L3 Routing LER LER Interne t L3 Routing L3 Routing LER LSR LSR Label Swapping Label Swapping LERL3 Routing L3 Routing IP Packet IP Packet w/ Label
  10. 10. MPLS Terminology• LDP: Label Distribution Protocol• FEC: Forwarding Equivalence Class• LSP: Label Switched Path• LSR: Label Switching Router• LER: Label Edge Router
  11. 11. MPLS Label Distribution Protocol• LDP - a set of procedures by which one LSR informs the other of the FEC-to-Label binding it has made.• Currently, several protocols used as Label Distribution Protocol (LDP) are available: – RSVP-TE (MPLS extension) —used for traffic engineering and resource reservation. – LDP and CR-LDP—maps unicast IP destinations into labels. – BGP—external labels (VPN)
  12. 12. Forwarding Equivalence Classes LSR LSR LER LER LSPIP1 IP1 IP1 #L1 IP1 #L2 IP1 #L3 IP2 #L1 IP2 #L2 IP2 #L3IP2 IP2 Packets are destined for different address prefixes, but can be mapped to common path • A group of packets that require the same forwarding treatment across the same path • Packets are grouped based on any of the following  Address prefix  Host address  Quality of Service (QoS) • FEC is encoded as the label
  13. 13. FEC Classification•A packet can be mapped to a particular FEC based on the following criteria: •destination IP address, •source IP address, •TCP/UDP port, •in case of inter AS-MPLS, Source-AS and Dest-AS, •class of service, •application used, Ingress Label FEC Egress Label 6 138.120.6/24 - xxxx 9•FECs are manually initiated by the operator•A FEC is associated at least one Label Ingress Label Ingress Label FEC FEC Attribute Egress Label Attribute Egress Label 6 138.120.6/24 - xxxx A 9 6 138.120.6/24 - xxxx B 12
  14. 14. Label Switched Path (LSP) Intf Label Dest Intf Label Intf Label Dest Intf In In Out Out In In Out 3 0.50 47.1 1 0.40 3 0.40 47.1 1 IP 1 47.1 Intf Dest Intf Label 3 In Out Out 3 3 47.1 1 0.50 2 1 1 2 47.3 3 47.2 2 IP types of Label Switched Paths: • Hop by hop) • Explicit Routing (LDP+”ER”)
  15. 15. Hop by Hop RoutingRoute={A,B,C} #14 #972 #216 B #14 C A #972 #462 It follows route that source chooses. In other words, the control message to establish the LSP (label request) is source routed.
  16. 16. EXPLICITLY ROUTED LSP ER-LSP Intf Label Dest Intf Label Intf Label Dest Intf In In Out Out In In Out 3 0.50 47.1 1 0.40 3 0.40 47.1 1Intf Dest Intf LabelIn Out Out IP 1 47.13 47.1.1 2 1.33 3 33 47.1 1 0.50 2 1 1 2 47.3 3 47.2 2IP
  17. 17.  Label Switch Router- An LSR is a high-speed router device in the core of an MPLS network that participates in the establishment of LSPs using the appropriate label signaling protocol and high-speed switching of the data traffic based on the established path.• Label Edge Router- An LER is a device that operates at the edge of the access network and MPLS network. LER’s support multiple port connected to dissimilar networks(such as frame relay ,ATM, and Ethernet) and forward this traffic on the MPLS.
  18. 18. Traffic Engineering B C Demand A DTraffic engineering is the process of mapping traffic demand onto a network it’s a mainAPPLICATION of mpls. Network Topology Purpose of traffic engineering: • Maximize utilization of links and nodes throughout the network • Engineer links to achieve required delay, grade-of-service • Spread the network traffic across network links, minimize impact of single failure • Ensure available spare link capacity for re-routing traffic on failure • Meet policy requirements imposed by the network operator Traffic engineering key to optimizing cost/performance
  19. 19. MPLS VPN : MPLS topology VPN 2 LSR138.120.8.0/24 Site B VPN 1 Site A LSP 47 ISP Backbone LSR LSR LSR LSR LSP 32 LSR Site A Site B VPN 2 VPN 1
  20. 20. Loop Handling Routing protocols used in conjunction with MPLS are based on distributed computation which may contain loops.Loop Handling  Ensures that loops are never set up  labels are not used until it is sure to be loop free  Methods ◦ labels are propagated starting at the egress switch ◦ use source routing to set up label bindings from the egress switch to each ingress switch Contd .
  21. 21. Leaf Leaf Leaf Detects loop immediately Link removed Change in Link from tree LSR Ingress Node Egress Node
  22. 22. MPLS Advantages Simplified Forwarding Efficient Explicit Routing Traffic Engineering QoS Routing Mappings from IP Packet to Forwarding Equivalence Class (FEC) Partitioning of Functionality Common Operation over Packet and Cell media
  23. 23. MPLS- the Future• Who will use MPLS? – Large-scale data networks used by Enterprises, Carriers and ISPs.• Why MPLS? -Leverage existing ATM hardware -Ultra fast forwarding -IP Traffic Engineering -Constraint-based Routing -Virtual Private Networks -Controllable tunneling mechanism -Voice/Video on IP -Delay variation + QoS constraints
  24. 24. Summary MPLS is an exciting promising emerging technology Basic functionality (Encapsulation and basic Label Distribution) has been defined by the IETF Traffic engineering based on MPLS/IP is just round the corner. Convergence is one step closer …...
  25. 25. Conclusion Providing QoS and traffic engineering capabilities in the Internet is very essential. For this purpose, the current Internet must be enhanced with new technologies such as MPLS. MPLS will play a key role in future service providers and carriers IP backbone networks. The use of MPLS in IP backbone networks will facilitate the development of new services such as real-time applications in the Internet.