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ITEC4610 Network Switching and Routing

ITEC4610 Network Switching and Routing. ดร. ประวิทย์ ชุมชู หัวหน้าสาขาวิชาวิศวกรรมสารสนเทศและการสื่อสาร (ICE) MUT Email: prawit@mut.ac.th ห้องทำงาน : F402 เบอร์โทรศัพท์ที่ทำงาน : (02)9883655 ต่อ 220 เบอร์โทรศัพท์เคลื่อนที่ : 065343850. Class XI MPLS (Multiprotocol Label Switching).

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ITEC4610 Network Switching and Routing

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  1. ITEC4610Network Switching and Routing ดร. ประวิทย์ ชุมชู หัวหน้าสาขาวิชาวิศวกรรมสารสนเทศและการสื่อสาร(ICE) MUT Email: prawit@mut.ac.th ห้องทำงาน: F402 เบอร์โทรศัพท์ที่ทำงาน: (02)9883655 ต่อ 220 เบอร์โทรศัพท์เคลื่อนที่: 065343850

  2. Class XIMPLS (Multiprotocol Label Switching) ดร. ประวิทย์ ชุมชู หัวหน้าสาขาวิชาวิศวกรรมสารสนเทศและการสื่อสาร(ICE) MUT Email: prawit@mut.ac.th ห้องทำงาน: F402 เบอร์โทรศัพท์ที่ทำงาน: (02)9883655 ต่อ 220 เบอร์โทรศัพท์เคลื่อนที่: 065343850

  3. Outlines • Motivation • MPLS Overview • MPLS Operation and Components

  4. Motivation • IP The first defined and used protocol De facto the only protocol for global internet working … but there are disadvantages

  5. Motivation • IP Routing disadvantages: • Connectionless e.g. no QoS • Each router has to make independent forwarding decisions based on the IP-address • Large IP Header At least 20 byte outing in Network Layer • Slower than Switching

  6. Motivation • ATM • connection oriented • Supports QoS • fast packet switching with fixed length packets(cells) • integration of different traffic types (voice, data,video) … but there are also disadvantages

  7. Motivation • ATM disadvantages • Complex • Expensive • Not widely adopted

  8. Motivation • Traditional Routing and packet switching • A simple-software-based router platform • L2 switching (Hardware) for local network

  9. Motivation Combine the forwarding algorithm used in ATM with IP.

  10. Outlines • Motivation • MPLS Overview • MPLS Operation and Components

  11. MPLS Overview MPLS is arranged between Layer 2 and Layer 3

  12. MPLS Functions • Specified mechanisms to manage traffic flows of various granularities, such as flows between different hardware, machines, or even flow between different applications • Remains independent of the Layer-2 and Layer-3 Protocols • Provides a means to map IP addresses to simple, fixed-length labels used by different packet-forwarding and packet-switching technologies • Interfaces to existing routing protocols such as resource reservation protocol (RSPV) and open shortest path first (OSPF) • Supports the IP, ATM, and Frame-relay Layer 2 protocols

  13. MPLS Example

  14. MPLS Example

  15. Outlines • Motivation • MPLS Overview • MPLS Operation and Components

  16. MPLS Operation • Label Creation and Distribution • Table Creation at each router • Label-switched path creation • Label insertion/table lookup • Packet forwarding

  17. MPLS components • LSRs (Label Switching Router) & LERs (Label Edge Routers) • FEC (Forward Equivalence Class) • Label &Label Blinding

  18. MPLS components • LER (Label Edge Router) • Resides at the edge of an MPLS network and assigns and removes the labels from the packets. • LSR (Label Switching Router) • Is a high speed router in the core on an MPLS network. • ATM switches can be used as LSRs without changing their hardware. Label switching is equivalent to VP/VC switching.

  19. Label • The labels are used to forward the packets on their way ( switching). • The labels change during transmission. • Hardware can be used to switch packets quickly between links.

  20. Label Format

  21. Label Details

  22. Label Creation • Topology-based method • Uses normal processing of routing protocol (such as OSPF and BGP) • Request-based method • Uses processing of request-based control traffic (such as RSVP) • Traffic-based method • Uses The reception of a packet to trigger the assignment and distribution of a lable

  23. Label Distribution • LDP (Label Distribution Protocol) • Maps unicast destination into labels • RSVP, CR-LDP • Used for traffic engineering and resource • PIM (Protocol-Independent multicast (PIM)) • Used for multicast states label mapping • BGP • External Label (VPN)

  24. Label-Switched Path (LSPs) • Hop-by-hop routing • Each LSR independent selects the next hop for a given FEC. This methodology is similar to that currently used in IP networks. The LSR uses any a viable routing protocols, such as OSPF, ATM private network-to-network interface (PNNI), etc. • Explicit routing • Explicit Routing is similar to source routing. The ingress LSR specifies the list of nodes through which the ER-LSP traverses. The path specified could be nonoptimal, as well.

  25. LSP Details • MPLS provides two options to set up an LSP • hop-by-hop routing: • Each LSR independently selects the next hop for a given FEC. LSRs support any available routing protocols ( OSPF, ATM …). • explicit routing: Is similar to source routing. The ingress LSR specifies the list of nodes through which the packet traverses. • The LSP setup for an FEC is unidirectional. • The return traffic must take another LSP!

  26. LSP • A path is established before the data transmission starts. • A path is a representation of a FEC. • FEC • The Forward Equivalence Class is a representation of a group of packets that share the same requirements for their transport. • The assignment of a particular packet to a particular FEC is done just once (when the packet enters the network).

  27. Label Space • Per Platform • The label values are unique across the whole LSR. The Label are allocated from a common pool. No two labels distributed on different have the same value. • Per Interface • The label ranges are associated with interfaces. Multiple label polls are defined for interface, and the labels provided on those interfaces are allocated from the separate polls. The label values provided on different interfaces could be the same.

  28. Label Merging • The incoming Streams of traffic from different interface can be merged together and switched using a common label if they are traversing the network toward the same final destination. This is known as strem merging or aggregation of flows • If the underlying transport network is an ATM networks, LSRs could employ virtual path (VP) or virtual channel (VC) merging

  29. Label Retention • Conservative • The binding between a label and an FEC received from LSRs that are not the next hop for a given FEC are discarded. This mode requires an LSR to maintain fewer Lables. • Liberal • The binding between a label and an FEC received from LSRs that are not the next hop for a given FEC are retained. This Mode allows for quicker adaptation to topology changes and allows for the switching of traffic to other LSPs in case of changes

  30. Label Control • Independent • An LSR recognizes a particular FEC and makes the decision to bind a label to the FEC independently to distribute the binding to its peers. The new FECs are recognized whenever new routes become visible to the router • Ordered • An LSR binds a label to a prticular FEC if and only if it is the egress router or it has received a label binding fro the FEC from its next hop LSR.

  31. Signaling Mechanisms • Label Request • An LSR requests a label from its downstream neighbor so that it can bind to a specific FEC • Label Mapping • In response to a label request, a downstream LSR will send a label to the upstream initiator using the label mapping mechanism

  32. Label Distribution Protocol • Discovery Messages • Announce and maintain the presence of an LSR in a network • Session Messages • Establish, maintain and terminate sessions between LDP peers • Advertisement Messages • Create, change and delete label mapping for FECs • Notification Messages • Provide advisory information and signal error information

  33. Label Stack • The label stack mechanism allows for hierarchical operation in the MPLS domain. It basically allows MPLS to be used simultaneously for routing at the fine-grain level • Each level in a label stack pertains to some hierarchical level. This facilitates a tunneling mode of operation in MPLS

  34. CR (Constraint-based routing) • CR takes into account parameters such as link characterisitcs (bandwidth, delay, etc. ), hop count and QoS • The LSP that are established could be CR-LSPs, where the constraints could be explicit hops or QSOS requirements

  35. Advantages of MPLS • Routing takes place only in the LERs (Label Edge Router) • Label switching increases speed • Provides Quality of Service • It hides the link layer and the differences between different Layer 2 protocols

  36. Disadvantages of MPLS • An additional layer is added • The router has to understand MPLS

  37. แบบสอบถามเพื่อการร่างหลักสูตร ปริญญาโทร สาขา Network engineering • เรียนวิชาอะไรบ้างตลอด 2 ปี • อยากเรียนวิชาหรือเนื้อหาอะไรเพิ่ม • อยากให้ตัดเนื้อหาอะไรออก • ลำดับวิชาที่เรียนควรเปลี่ยนหรือไม่ • ควรมี Lab อะไรเพิ่มหรือเปล่า • ควรปูพื้นวิชาอะไรหรือเนื้อหาอะไร

  38. โครงสร้างหลักสูตรใหม่โครงสร้างหลักสูตรใหม่

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