Did MPOA achieve its objective TERENA Networking Conference

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 http: //www. gmd. de

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 2

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. 3

The Development of MPOA Standardization 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) 4

The Development of MPOA History – 1995: 1 st draft of the Control Signaling Working Group – Two years discussion phase – imposed restrictions upon the original concept (e. g. , virtual router, multicast, Qo. S) – 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 v 1. 1 Addendum on VPN Support – establishment of new ATM-IP Collaboration Working Group 5

The Concept of MPOA NHRP Resolution Response Ingress MPS NHRP Resolution Response Egress MPS NHRP Resolution Request MPOA Resolution Response MPOA Cache Imposition Request MPOA Resolution Request Ingress MPC MPOA Shortcut Egress MPC 6

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 7

MPOA - Architecture I Host Router MPC MPS Router MPS ELAN 1 LEC MPC ELAN 1 ELAN 2 MPC Host MPC LEC ELAN 1 ELAN 2 Host Router MPS LEC ELAN 2 MPS MPC ELAN 1 ELAN 2 LEC ELAN 1 ELAN 2 8

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

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 10

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

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 12

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

MPOA - Availability and Redundancy – Redundant LANE server – LANE v 2 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 14

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 15

Practical Experience with MPOA I Components 16

Example from the Test Scenarios FORE ASX 4000 LES/BUS - mpoa 85 LECS FORE ASX 1000 Cisco 4500 Cisco LS 1010 MPS - mpoa 83 / mpoa 85 LEC - mpoa 83 / mpoa 85 FORE Powerhub 7000 FORE ASX 1000 MPS - mpoa 82 / mpoa 85 LECS GN Nettest Cisco Catalyst 5505 LES/BUS - mpoa 82/mpoa 83 LEC/MPC - mpoa 83 Shortcut FORE ES 3810 LEC/MPC - mpoa 82 Legend: PC NT 4. 0 mpoa 83 PC Windows 98 mpoa 82 622 Mbps 155 Mbps 100 Mbps Ether

Practical Experience with MPOA II Results – 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? 18

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 Qo. S are being discussed – open discussion about integrated or differentiated services 19

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 20

Comparison of MPOA and MPLS 21

Conclusion – MPOA will not be a success – – – high complexity and as consequence high management costs new technologies provide simpler solutions than MPOA 802. 1 q (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, Qo. S and Multicast 22