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MPLS TE Over ATM

MPLS TE Over ATM. Advisor: Dr. Ravi Pendse Presented by: Deepak Gulla Nishant Tambe. Outline. Goals MPLS basics with Traffic Engineering ATM basics with ATM Traffic Management Network Scenario Results / Observations Conclusions Future Work. Goals.

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MPLS TE Over ATM

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  1. MPLS TE Over ATM Advisor: Dr. Ravi Pendse Presented by: Deepak Gulla Nishant Tambe

  2. Outline • Goals • MPLS basics with Traffic Engineering • ATM basics with ATM Traffic Management • Network Scenario • Results / Observations • Conclusions • Future Work

  3. Goals • Effects of link loading and link failure on an ATM network running MPLS Traffic Engineering (TE) • Behavior of Non-Real Time Traffic • Behavior of Real Time Traffic

  4. Overview Model

  5. Basic Network Scenario R8 ATM LSR hosts R4 ATM 2 ATM 1 hosts ATM 3 Edge LSR R5 R7 LSR: Label Switch Router LC-ATM: Label Controlled ATM Links used : OC-3 ( 155.4 Mbps) LC-ATM Interfaces

  6. What is MPLS? • It’s a high performance method for forwarding packets through a network. • It’s a multi protocol because it can work with protocols like OSPF,RSVP,LDP, BGP etc. • It uses label (a short fixed length) with packet. • All packets with same label use the same path - a so-called label switched path (LSP). Because labels refer to paths and not endpoints, packets destined for the same endpoint can use a variety of LSP’s to get there.

  7. Why MPLS? • Fast forwarding • Traffic Engineering • Virtual Private Networks • It combines the scalability and flexibility of routing with performanceof layer 2.

  8. MPLS Label Format

  9. Label Distribution Protocol Network 130.10.X.X / 24 Request 56.2 Request 56.2 56.2 56.1 1 2 1 2 1 2 Mapping 0.40 Mapping 0.30 3 3 3 3 3 56.3 2 1 2 1 2 1

  10. MPLS Operation • Label creation and distribution • LFIB table at each router • Label switching path and table lookup • Forwarding of packet through the network

  11. MPLS Traffic Engineering • Optimizes the routing of IP traffic. • Routes traffic flows across the network based on resources the flow requires and the resources available. • Employs “Constraint-based routing” • Recovers to link or node failures that change the topology. • Routing protocol used must be a link state protocol.

  12. ATM • ATM is a ITU-T standard for a cell relay wherein information for services is conveyed in small, fixed size cells. • ATM is a cell switching and multiplexing technology that combines the benefits of circuit switching with those of packet switching. • The cell size in ATM is 53 bytes where the payload is of 48 bytes and the 5 bytes constitutes for the header information. • It’s a connection oriented duplex communication network.

  13. Why ATM ? • Integrated Services • High speed • Scalable • Quality of service • Well established industry standard • Faster more efficient switching

  14. ATM Cell 7 6 5 4 3 2 1 0 Generic Flow Ctrl. Virtual Path IE Virtual Channel IE Virtual Path IE Virtual Channel IE 5 Bytes Virtual Channel IE Payload Type IE CLP Header Error Check Payload (48 bytes) 48 Bytes

  15. Cell Header • VPI/VCI - Used to route cell to destination • 24 bit information, routing significance only • CLP - Cell Loss Priority • 1: discard first; 0: try not to discard • PT - Payload Type • Data or OAM (Operation, Administration, Maintenance) • Congestion indication • End of AAL5 packet • GFC - Generic Flow Control (UNI only) local functions

  16. Types of ATM Connections • PVC (Permanent Virtual Connections) • SVC (Switched Virtual Connections) • Fundamental Connections • Point-to-point • Point-to-multipoint ATM CoS • Constant Bit Rate (CBR) • Variable Bit Rate- Real time (VBRrt) • Variable Bit Rate- Nonreal time (VBRnrt) • Unspecified Bit Rate (UBR) • Available Bit Rate (ABR)

  17. Connection setup through ATM Connects to B Connects to B OK End system A OK Connects to B Connects to B OK • Signaling request • Connection routed – setup path • Connection accepted /rejected • Data flow- along same path • Connection tear down End system B

  18. ATM Switching Operation 35 Input Output 25 45 2 1 3 25 • Receives cell across a link on a known VCI or VPI value • Translation table lookup takes place to determine the • outgoing port and new VPI / VCI value is assigned. • Retransmits cell on that outgoing link with appropriate • identifiers

  19. Basic Network Scenario R8 ATM LSR hosts R4 ATM 2 ATM 1 hosts ATM 3 Edge LSR R5 R7 LSR: Label Switch Router LC-ATM: Label Controlled ATM Links used : OC-3 ( 155.4 Mbps) LC-ATM Interfaces

  20. Phase 1: MPLS TE over ATM ( NRT) Pagent on R2 R1 5.1 R8 ATM LSR R3 1.2 4.2 R4 ATM 2 1.1 Path 2 2.1 ATM 1 Pagent Path 5.2 4.1 2.2 ATM 3 Edge LSR 9.1 3.1 3.2 R7 R5 Path 1 9.2 LC-ATM Interfaces Pagent on R6 LSR: Label Switch Router LC-ATM: Label Controlled ATM Links used : OC-3 ( 155.4 Mbps) P a t h 1 P a t h 2 P a g e n t p a t h

  21. Result of Phase 1 MPLS forwarding table with TE configured:

  22. Result of Phase 1: Route taken before change of Tunnels (with Label info): rack7r5#trace 10.10.10.5 Type escape sequence to abort. Tracing the route to 10.10.10.5 1 100.1.2.2 [MPLS: Label 27 Exp 0] 92 msec 204 msec 160 msec 2 100.1.3.2 116 msec 112 msec * Ping traffic showing packets drop: rack7r5#ping 10.10.10.5 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 10.10.10.5, timeout is 2 seconds: ...!! Success rate is 40 percent (2/5), round-trip min/avg/max = 28/28/28 ms

  23. Result of Phase 1 Ping showing 100% success after change of Tunnels: rack7r5#ping 10.10.10.5 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 10.10.10.5, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 28/34/60 ms Route taken after change in Tunnels (with label info): rack7r5#trace 10.10.10.5 Type escape sequence to abort. Tracing the route to 10.10.10.5 1 100.1.1.2 [MPLS: Label 29 Exp 0] 36 msec 36 msec 36 msec 2 100.1.4.1 20 msec 16 msec *

  24. Phase 2: MPLS TE over ATM ( RT) R1 Pagent on R2 5.1 R8 R3 1.2 4.2 Path 2 R4 ATM 2 1.1 T1 Link 2.1 ATM 1 GW Pagent Path 5.2 ATM 3 4.1 2.2 R7 Callgen R1 9.1 3.1 3.2 R5 Path 1 GW 9.2 PSQM Server T1 Link Pagent on R6 Callgen R2

  25. Result of Phase 2 Route taken before starting the call: rack7r5#trace 10.10.10.5 Type escape sequence to abort. Tracing the route to 10.10.10.5 1 100.1.2.2 [MPLS: Label 16 Exp 0] 152 msec 76 msec 80 msec 2 100.1.3.2 64 msec 248 msec * Route taken after change the call: rack7r5#trace 10.10.10.5 Type escape sequence to abort. Tracing the route to 10.10.10.5 1 100.1.1.2 [MPLS: Label 32 Exp 0] 36 msec 36 msec 36 msec 2 100.1.4.1 20 msec 20 msec *

  26. Results of Phase 2:

  27. Observations • During congestion MPLS automatically switches the path to the other path that is under utilized. • LS1010 is not working as LSR when configured along with the 3600 series routers with the existing IOS, hence we cannot use SVC’s. • The success rate of the call increased by increasing the PCR value of the switch. • Due to the configuration done codecs G.729 and G.723 also yielded better results when compared to other codecs inspite of their lower bit rate

  28. Goals • Effects of link loading and link failure on an ATM network running MPLS Traffic Engineering (TE) • Behavior of Non-Real Time Traffic • Behavior of Real Time Traffic

  29. Conclusions • The PSQM scores obtained were better for all scenarios by configuring MPLS TE with ATM TM. • Recovery of links is faster when MPLS TE with ATM TM is used. • G.723 inspite of lower bit rate yielded comparably equivalent scores hence for our scenario we would recommend using it.

  30. Future Work • MPLS QoS can be implemented on the existing scenario by replacing 3600 series with 7200 series routers. • ATM QoS can be implemented by replacing LS1010’s with that of MGX 8500 series switches. • Implement VPN extending our existing network scenario. • Behavior of real time traffic with more number of calls. • Measure parameters such as jitter, echo, delay etc.

  31. References • MPLS Technology and Applications – Bruce David & Yakov Rekhter • Cisco ATM Solutions – Cisco Press • www.Cisco.com • RFC 3031 • www.mplsrc.com

  32. Have you had Donuts? If not, Please help yourself ! Questions, if any ?

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