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Did MPOA achieve its objective? TERENA Networking Conference 2000 Lisbon, Portugal 22-25 May 2000

Did MPOA achieve its objective? TERENA Networking Conference 2000 Lisbon, Portugal 22-25 May 2000. Ferdinand Hommes, Eva Pless, Lothar Zier GMD - German National Research Center for Information Technology. Contents. The Development of MPOA The Concept of MPOA

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Did MPOA achieve its objective? TERENA Networking Conference 2000 Lisbon, Portugal 22-25 May 2000

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  1. Did MPOA achieve its objective?TERENA Networking Conference 2000Lisbon, Portugal22-25 May 2000 Ferdinand Hommes, Eva Pless, Lothar Zier GMD - German National Research Center for Information Technology

  2. Contents • The Development of MPOA • The Concept of MPOA • The Implementation of MPOA and its Problems • Practical Experience with MPOA • Extensions of MPOA • MPLS - an Alternative Approach to MPOA? • Conclusion

  3. The Objective of MPOA • The main goal of MPOA is the efficient transmission of unicast data between subnets in a LAN Emulation environment. • The basic principle is the bypassing of routers by setting up ATM shortcuts between edge devices.

  4. The Development of MPOAStandardization Comittees • MPOA is based on LAN Emulation over ATM and on the Next Hop Resolution Protocol • ATM-Forum • LAN Emulation (LANE) • Multi-Protocol over ATM (MPOA) • IETF • Next Hop Resolution Protocol (NHRP)

  5. The Development of MPOAHistory • 1995: 1st draft of the Control Signaling Working Group • Two years discussion phase • imposed restrictions upon the original concept(e.g., virtual router, multicast, QoS) • transfered specification work to the LANE/MPOA working group • objective: no modifications of existing systems • 1997: Multi-Protocol Over ATM 1.0 • 1998: MPOA MIB 1.0 • 1999: Termination and Transfer • release of MPOA specification version 1.1 • authentification, MIB 1.0 und PICS • MPOA v1.1 Addendum on VPN Support • establishment of new ATM-IP Collaboration Working Group

  6. The Concept of MPOA NHRP Resolution Response NHRP Resolution Response IngressMPS NHS EgressMPS NHRP Resolution Request NHRP Resolution Request MPOACache ImpositionResponse MPOAResolutionResponse MPOACache ImpositionRequest MPOAResolutionRequest IngressMPC EgressMPC MPOA Shortcut

  7. MPOA - Architecture II • Automatic discovery of MPC and MPS by extended LANE control messages • simple configuration • discovery problems: some times several tries • Variants of cooperation for MPS, MPC und LEC • normally manufacturer implement only one variant • interoperability problems are foreseeable • Varying implementations of control flow

  8. MPS MPS MPS MPS MPS LEC LEC MPC LEC MPC LEC MPC MPOA - Architecture I Router Host Router Router ELAN1 ELAN2 MPC MPC ELAN1 ELAN2 ELAN1 ELAN2 Host MPC Host Router LEC LEC MPC MPC ELAN1 ELAN2 ELAN1 ELAN2 ELAN1 ELAN2

  9. MPC MPC MPC MPC MPOA - Flow of Control MPS MPS Cisco NHRP FORE MPOA Control Messages MPOA Control Messages and MPOA Keep-Alive MPOA Keep-Alive MPOA Data or Purge Messages Legend: Point-to-Point Point-to-Multipoint

  10. MPOA - Shortcuts • MPC detects data flow and sets up shortcut • Flow qualification: number of packets per second • No shortcut for broadcast or multicast data • Unidirectional and bidirectional shortcuts • Internal shortcut between MPCs on same edge device are possible • Great variety of transmission paths • complicates analysis of data loss and component malfunction

  11. case 6 case 5 case 4 case 1 case 2 case 3 MPC MPC MPC MPC MPC MPC MPC MPC MPC MPC MPC MPC MPC MPOA - Shortcuts I MPS NHS MPS MPC

  12. MPOA - Security I • Security risks • normal IP security devices can be bypassed, if the end system is allowed to set up short cuts • known security problems for ATM connection setup apply • several MPSs on same router • Some solutions • MPOA 1.1 Authentication Extension (MPC/MPS) • Addendum for VPN Support

  13. MPOA - Security II MPC1 MPS 1+2 (filter defined) MPS 3+4 (filter defined) MPC3 net 1 net 5 net 3 ATM network net 2 net 4 MPC2 MPC4 Legend: IP net shortcut allowed shortcut not allowed

  14. MPOA - Availability and Redundancy • Redundant LANE server • LANE v2 LNNI Specification (ATM Forum, February 1999) • Server Cache Synchronisation Protocol (SCSP), IETF 1998 • few implementations • Redundant router • Virtual Router Redundancy Protocol (VRRP), IETF 1998 • few implementations

  15. MPOA - Management and Operation • Management by SNMP • MIBs defined by ATM Forum and IETF • proprietary MIBs (slow standardization process) • Expensive management • lots of components (LANE server, router, switches) • layer 2 (ATM/Ethernet switches) and layer 3 (router) management • separate management of layers not efficient • integrated management applications not available • No tools for evaluation and configuration of flow qualification

  16. Practical Experience with MPOA IComponents

  17. Example from the Test Scenarios Cisco 4500 FORE ASX 4000 Cisco LS1010 MPS - mpoa83 / mpoa85 LES/BUS - mpoa85 LEC - mpoa83 / mpoa85 LECS FORE Powerhub 7000 FORE ASX 1000 FORE ASX 1000 MPS - mpoa82 / mpoa85 LEC - mpoa82 / mpoa85 LECS GN Nettest Cisco Catalyst 5505 Shortcut FORE ES 3810 LES/BUS - mpoa82/mpoa83 LEC/MPC - mpoa82 LEC/MPC - mpoa83 Legend: 622 Mbps PC Windows 98 PC NT 4.0 155 Mbps mpoa82 100 Mbps Ether mpoa83

  18. Practical Experience with MPOA IIResults • Interoperability problems between MPOA components of different manufacturers • partly resolved within test • Communication between MPSs requires LANE • Performance rates for workstations came up to expectation • Performance rates for Ethernet switches didn’t come up to expectation • inefficient implementation of MPCs?

  19. Extensions of MPOA • Support of Virtual Private Networks (VPN) • VPN-Identification for correct separation of VPNs • released in October 1999 • Quality of Service Extension MPOA • MPOA only defined for UBR connections • Extensions of QoS are being discussed • open discussion about integrated or differentiated services

  20. MPLS - an Alternative Approach to MPOA? • Multiprotocol Label Switching (MPLS) • drafts in discussion at IETF • technique for WAN • independent of physical networking layer (ATM, Frame Relay, Packet over Sonet, etc.) • support of multicast transmission • support of Quality of Service or Class of Service • extension of normal IP routing by explicit routing • traffic engineering

  21. Comparison of MPOA and MPLS

  22. Conclusion • MPOA will not be a success • high complexity and as consequence high management costs • new technologies provide simpler solutions than MPOA • 802.1q (VLAN-trunking) for Fast and Gigabit Ethernet • ATM to the desktop didn’t succeed • routers based on ASICs route with full line rate (applies to 155 and 622 Mbps) • MPLS will succeed in WAN • support of Traffic Engineering, QoS and Multicast

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