Broadband Network Presentation


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These slides were presented to the broadband networks course at our university MAJU.
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Broadband Network Presentation

  1. 1. Topic: Multi-Protocol Label Switching (MPLS) Broad Band Network
  2. 2. Agenda <ul><li>MPLS - The Motivation </li></ul><ul><li>How MPLS Works ! </li></ul><ul><li>MPLS Technology </li></ul><ul><li>MPLS Application </li></ul><ul><li>MPLS Advantages </li></ul><ul><li>MPLS Future </li></ul><ul><li>MPLS Vendors </li></ul><ul><li>Demonstration </li></ul>
  3. 3. MPLS - The Motivation <ul><li>IP Protocol Suite - the most predominant networking technology. </li></ul><ul><li>Voice & Data convergence on a single network infrastructure. </li></ul><ul><li>Continual increase in number of users. </li></ul><ul><li>Demand for higher connection speeds. </li></ul><ul><li>Increase in traffic volumes. </li></ul><ul><li>Ever-increasing number of ISP networks. </li></ul>
  4. 4. MPLS Working Groups and Standards <ul><li>Standardized by the IETF </li></ul><ul><li>MPLS core components are generic </li></ul><ul><li>MPLS doesn’t use specific technology process (e.g. ATM/FR signaling protocol PNNI ) </li></ul>
  5. 5. MPLS and ISO model PPP 2 4 Frame Relay ATM (*) TCP UDP MPLS IETF main goal is that when a layer is added, no modification is needed on the existing layers. All new protocol must be backward compatible Physical (Optical - Electrical) 1 IP 3 Applications 7 to 5 PPP FR ATM (*)
  6. 6. MPLS Cloud LSR LER LSR LER IP Packet IP Packet Label L3 Routing L3 Routing Label Swapping Label Swapping LER LER LER L3 Routing L3 Routing L3 Routing
  7. 7. MPLS Link Layers & Label Encapsulation ATM FR Ethernet PPP VPI VCI DLCI “ Shim Label” Layer2 “ Shim header” ……. IP | PAYLOAD
  8. 8. Some MPLS Terms... <ul><li>LER - Label Edge Router </li></ul><ul><li>LSR - Label Switch Router </li></ul><ul><li>FEC - Forward Equivalence Class </li></ul><ul><li>Label - Associates a packet to a FEC </li></ul><ul><li>Label Stack - Multiple labels containing information on how a packet is forwarded. </li></ul><ul><li>Shim - Header containing a Label Stack </li></ul><ul><li>Label Switch Path - path that a packet follows for a specific FEC </li></ul><ul><li>LDP - Label Distribution Protocol, used to distribute Label information between MPLS-aware network devices </li></ul><ul><li>Label Swapping - manipulation of labels to forward packets towards the destination. </li></ul>
  9. 9. What is Multi-Protocol Label Switching (MPLS) <ul><li>MPLS is a hybrid model adopted by IETF to incorporate best properties in packet routing. </li></ul><ul><li>A. MPLS is a packet-forwarding technology which uses labels to make data forwarding decisions. With MPLS, the Layer 3 header analysis is done just once (when the packet enters the MPLS domain). Label inspection drives subsequent packet forwarding. MPLS provides these beneficial applications: </li></ul><ul><li>Virtual Private Networking (VPN) </li></ul><ul><li>Traffic Engineering (TE) </li></ul><ul><li>Quality of Service (QoS) </li></ul><ul><li>ATM over MPLS (AToM) </li></ul>
  10. 10. What is a label? What is the structure of the label? <ul><li>A label is a short, four-byte, fixed-length, locally-significant identifier which is used to identify a Forwarding Equivalence Class (FEC). The label which is put on a particular packet represents the FEC to which that packet is assigned. </li></ul><ul><li>Label—Label Value (Unstructured), 20 bits </li></ul><ul><li>Exp—Experimental Use, 3 bits; currently used as a Class of Service (CoS) field. </li></ul><ul><li>S—Bottom of Stack, 1 bit </li></ul><ul><li>TTL—Time to Live, 8 bits </li></ul>
  11. 11. Where will the label be imposed in a packet <ul><li>The label is imposed between the data link layer (Layer 2) header and network layer (Layer 3) header. The top of the label stack appears first in the packet, and the bottom appears last. </li></ul>
  12. 12. The MPLS Shim Header <ul><li>The Label (Shim Header) is represented as a sequence of Label Stack Entry </li></ul>Label : Label value (0 to 15 are reserved for special use) Exp : Experimental Use S : Bottom of Stack (set to 1 for the last entry in the label) TTL : Time To Live Label (20 bits) Exp (3 bits) S (1 bit) TTL (8bits)
  13. 13. What is a Forwarding Equivalence Class (FEC) <ul><li>FEC is a group of IP packets which are forwarded in the same manner, over the same path, and with the same forwarding treatment. </li></ul><ul><li>An FEC might correspond to a destination IP subnet, but it also might correspond to any traffic class that the Edge-LSR considers significant. </li></ul>
  14. 14. FEC Classification Ingress Label FEC Egress Label 6 138.120.6/24 - xxxx 9 Ingress Label Attribute FEC Egress Label Ingress Label FEC Egress Label 6 138.120.6/24 - xxxx 9 Attribute A 6 138.120.6/24 - xxxx 12 B <ul><li>A FEC is associated at least one Label </li></ul><ul><li>A packet can be mapped to a particular FEC based on the following criteria: </li></ul><ul><ul><li>destination IP address, </li></ul></ul><ul><ul><li>source IP address, </li></ul></ul><ul><ul><li>TCP/UDP port, </li></ul></ul><ul><ul><li>in case of inter AS-MPLS, Source-AS and Dest-AS, </li></ul></ul><ul><ul><li>class of service, </li></ul></ul><ul><ul><li>application used, </li></ul></ul><ul><ul><li>… </li></ul></ul><ul><ul><li>any combination of the previous criteria. </li></ul></ul>
  15. 15. MPLS Operation 1a. Routing protocols (e.g. OSPF) exchange reachability to destination networks 1b. Label Distribution Protocol (LDP) establishes label mappings to destination network 2. Ingress LER receives packet and “label”s packets IP IP 10 3. LSR forwards packets using label swapping IP 20 IP 40 4. LER at egress removes label and delivers packet IP
  16. 16. <ul><li>Label-switching router (LSR): </li></ul><ul><li>A device such as a switch or a router that forwards labeled entities based upon the label value. </li></ul><ul><li>Label switch controller (LSC): </li></ul><ul><li>An LSR that communicates with an ATM switch to provide and provision label information within the switch. </li></ul><ul><li>Label Distribution Protocol (LDP): </li></ul><ul><li>A set of messages defined to distribute label information among LSRs. </li></ul><ul><li>Label switch path (LSP): </li></ul><ul><li>The path defined by the labels through LSRs between end points. </li></ul><ul><li>label virtual circuit (LVC): </li></ul><ul><li>An LSP through an ATM system </li></ul>
  17. 17. What is an upstream label switch router (LSR), What is a downstream LSR <ul><li>Upstream and downstream are relative terms in the MPLS world. They always refer to a prefix (more appropriately, an FEC). These examples further explain this. </li></ul><ul><li>For FEC, R1 is the &quot;Downstream&quot; LSR to R2. </li></ul><ul><li>For FEC, R2 is the &quot;Upstream&quot; LSR to R1. </li></ul><ul><li>For FEC, R1 is the &quot;Downstream&quot; LSR to R2. And, R2 is the &quot;Downstream&quot; LSR to R3. </li></ul>
  18. 18. <ul><li>For FEC, R1 is the &quot;Downstream&quot; LSR to R2. For FEC, R2 is the &quot;Downstream&quot; LSR to R1. </li></ul><ul><li>Data flows from upstream to downstream to reach that network (prefix). </li></ul><ul><li>The R4 routing table has R1 and R2 as the &quot;next-hops&quot; to reach </li></ul>
  19. 19. MPLS Label Distribution Protocol <ul><li>LDP - a set of procedures by which one LSR informs the other of the FEC-to-Label binding it has made. </li></ul><ul><li>Currently, several protocols used as Label Distribution Protocol (LDP) are available: </li></ul><ul><ul><li>RSVP-TE (MPLS extension) </li></ul></ul><ul><ul><li>LDP and CR-LDP </li></ul></ul>
  20. 20. Downstream stream on demand Mapping 12 Mapping 5 5 12 12 5 Request 138.120 Request 138.120 The label is requested by the upstream node and the downstream node defines the label used. Ingress Interface Ingress Label FEC Egress Interface Egress Label 1 138.120 3 Ingress Interface Ingress Label FEC Egress Interface Egress Label 1 138.120 x 4 3 Ingress Interface Ingress Label FEC Egress Interface Egress Label 1 x 138.120 MPLS switch MPLS switch MPLS switch MPLS switch 1 2 3 1 2 3 1 2 3 4 1 2 3 138.120 192.168 127.20
  21. 21. Unsolicited Downstream Mapping 12 Mapping 5 5 12 12 5 The downstream node defines the label and advertises it to the upstream node. MPLS switch MPLS switch MPLS switch MPLS switch 1 2 3 1 2 3 1 2 3 4 1 2 3 138.120 192.168 127.20 Ingress Interface Ingress Label FEC Egress Interface Egress Label 1 138.120 3 Ingress Interface Ingress Label FEC Egress Interface Egress Label 1 138.120 x 4 3 Ingress Interface Ingress Label FEC Egress Interface Egress Label 1 x 138.120
  22. 22. Edge LSR Features <ul><ul><li>Routing protocols </li></ul></ul><ul><ul><li>FEC Classification </li></ul></ul><ul><ul><li>Initiates LSP setup for Downstream On Demand method </li></ul></ul><ul><ul><li>Adaptation of non-MPLS data to MPLS data </li></ul></ul><ul><ul><li>Layer 2 translation for MPLS data </li></ul></ul><ul><ul><li>Terminated MPLS-VPN </li></ul></ul><ul><ul><li>At least one LDP protocol </li></ul></ul><ul><ul><li>Edge LSR is counted into the TTL count as a regular router </li></ul></ul>
  23. 23. Core LSR Features <ul><ul><li>Routing protocols </li></ul></ul><ul><ul><li>Propagates Downstream On Demand method (request and mapping) </li></ul></ul><ul><ul><li>Layer 2 translation </li></ul></ul><ul><ul><li>High speed label forwarding/switching </li></ul></ul><ul><ul><li>At least one LDP protocol </li></ul></ul>
  24. 24. MPLS Advantages <ul><li>Simplified Forwarding </li></ul><ul><li>Efficient Explicit Routing </li></ul><ul><li>Traffic Engineering </li></ul><ul><li>QoS Routing </li></ul><ul><li>Mappings from IP Packet to Forwarding Equivalence Class (FEC) </li></ul><ul><li>Partitioning of Functionality </li></ul>
  25. 25. MPLS - the Future <ul><li>Who will use MPLS? </li></ul><ul><ul><li>Large-scale data networks used by Enterprises, Carriers and ISPs. </li></ul></ul><ul><li>Why MPLS? </li></ul><ul><ul><li>Delivers high speed L2 (really “Label”) switching at low cost vs. traditional L3 routing </li></ul></ul><ul><ul><li>Provides Traffic Engineering - allows the user to direct traffic based on network utilization and demand. </li></ul></ul><ul><ul><li>Ease of provisioning QoS </li></ul></ul><ul><ul><li>Support for VPNs </li></ul></ul>
  26. 26. Explicitly Routed LSP <ul><li>End-to-End forwarding decision determined by ingress node. </li></ul><ul><li>Enables Traffic Engineering </li></ul>LER 1 LSR 2 LSR 3 LER 4 Forward to LSR 2 LSR 3 LSR 4 LSR X Overload !! Overload !!
  27. 27. MPLS Traffic Engineering <ul><li>MPLS Traffic Engineering (TE) provides high quality IP service. </li></ul><ul><li>TE defines : </li></ul><ul><ul><li>LSP Admission Control (LAC) </li></ul></ul><ul><ul><li>IP traffic (policing or shaping) </li></ul></ul><ul><ul><li>IP service prioritization </li></ul></ul><ul><ul><li>Network capacity and growth capacity </li></ul></ul><ul><li>TE allows flexibility and customization. </li></ul>
  28. 28. MPLS - Some Major Vendors <ul><li>Alcatel </li></ul><ul><li>Cisco </li></ul><ul><li>Juniper Networks </li></ul><ul><li>Nortel </li></ul><ul><li>Lucent </li></ul>
  29. 29. MPLS - More Information @ <ul><li>MPLS Charter </li></ul><ul><li> </li></ul><ul><li>MPLS Resource Center </li></ul><ul><li>http:// </li></ul><ul><li>M PLS Forum </li></ul><ul><li>http:// </li></ul>
  30. 30. QOS of MPLS DEMO
  31. 31. THANKS