1. AIMS Workshop Heidelberg, 9-11 March 1998 P616 - ENHANCED ATM ISSUES Network Layers over ATM Rüdiger Geib Deutsche Telekom Tel. +49 6151 83-2138 Fax +49 6151 83-8103 geib@tzd.telekom.de

2. AIMS Workshop Heidelberg, 9-11 March 1998 P616 Task 4 Network Layers over ATM Aims: Analysis of new and evolving network layer protocols (and products) which use ATM functions Guidance to Telecommunication Network Operators for product selection by strong point/weak point analysis Items: MPOA, MPLS (and similar proposals), Winsock2

3. AIMS Workshop Heidelberg, 9-11 March 1998 P616 Task 4 Network Layers over ATM Usage of ATM & Addressing MPOA: Overlay attempt (addressing). This allows to use standard ATM and the usage of the ATM network without respecting the IP network architecture. By and large a more ATM friendly attempt MPLS: Peering attempt (addressing). This allows to use the standard IP Routing protocols also for the layer 2 (ATM) routing. Results in most cases in proprietary ATM control planes. Usage of ATM concentrated on point to point links between IP routers. By and large a more IP friendly attempt.

4. AIMS Workshop Heidelberg, 9-11 March 1998 P616 Task 4 Network Layers over ATM Differentiated QoS support MPOA: This topic is not part of MPOA 1.0. MPOA 1.0 is based on ATM UBR connections. MPLS: Generally main ideas are offered. By and large, all implementations are based on ATM UBR connections. One supplier seems to copy ATM services on IP level (with regard to queuing, tagging etc.). However no standardised QoS figures are available and no connection admission control is supported. Both will have to be developed by Network Operators using such equipment.

5. AIMS Workshop Heidelberg, 9-11 March 1998 P616 Task 4 Network Layers over ATM Scaleability MPOA: will easily scale for LANs. Possible problems in WANs: routing loops, amount of switched ATM connections, limits of the client server structure, address mapping table maintenance. MPLS: some of the different available proposals are scaleable only in a LAN environment. MPLS itself is mainly designed for the WAN area and its scaleability for WANs is a requirement.

6. AIMS Workshop Heidelberg, 9-11 March 1998 P616 Task 4 Network Layers over ATM Multicast MPOA 1.0 doesn't support any multicast (only LANE 2.0 supports this within the emulated LANs). MPLS may offer support of different standard IP multicast protocols. Real time services Neither MPOA nor MPLS offer any support of real time services. Security Neither MPOA nor MPLS offer any security features.

7. AIMS Workshop Heidelberg, 9-11 March 1998 P616 Task 4 Network Layers over ATM Future changes in the ATM layer Traffic shaping on ATM could help to solve many problems. A very important consequence: simultaneous multiplexing of different IP frames within one ATM VC is required. Multipoint to point VCs and VC merge or attempts helping to establish similar connection types. If appropriate, IP friendly changes in the ATM control plane may be considered (e.g. peering of routing mechanisms) All ATM switching protocols will have to be able to support switched UBR connections

8. AIMS Workshop Heidelberg, 9-11 March 1998 P616 Task 4 Network Layers over ATM PNO Guidelines MPOA is consisting of a lot of interfaces and protocols. Any supplier claiming support of MPOA may only support parts of it. Check the support for switched UBR connections by your ATM network and check whether the performance and scaleability of your MPOA network fit to your needs. MPLS is intended as a standard. All protocols required to support MPLS need to be standardised. Prevent proprietary solutions (e.g. ATM control plane, IP QoS differentiation). This development has just begun. Constant testing and improvement of standards should lead to market and customer oriented solutions within 2 - 4 years.

9. AIMS Workshop Heidelberg, 9-11 March 1998 P616 Task 4 Network Layers over ATM Winsock2 Application Protocol Interface A variety of network layer protocols (using a variety of transport layers) for an application. Real time service support is possible. Standard protocols of IETF, ATM Forum and ITU-T. The product itself is also standardised. Allows an interoperability of an application with a variety of protocols and implementations on the far end. Provides mechanisms to use differentiated QoS. DAVIC conform (will be pushed with Digital Video Broadcast). Independent of the hardware (running on different platforms).

10. AIMS Workshop Heidelberg, 9-11 March 1998 P616 Task 4 Network Layers over ATM Winsock2 Application Protocol Interface For implementers: Check the performance and the stability of the hardware and the availability of all desired protocol- software. As ATM/QoS part is optional only in the standard, demand its support. Push the suppliers to improve the overall quality of their WinSock2 products. Note that of course the detailed usage of the single protocols (selection of options, parameters and QoS parameter mappings) will have to be programmed locally. A video download application (server and client) could be demonstrated in two fairs in 1997.