Company Confidential 1 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials Towards a mobile content delivery network with a P2P architecture Carlos Quiroz

Company Confidential 2 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials Overview Analysis of P2P architecture for a mobile oriented content delivery system Open Questions Is there value on using P2P instead of traditional techniques for large scale delivery systems What characteristics of a delivery system for mobile devices make using P2P techniques appealing How to measure those benefits Hypothesis: A P2P architecture would enable certain scenarios involving mobile terminals not support by current architectures

Company Confidential 3 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials Content Sharing and Delivery Service Content Delivery network for both mobile and web based clients Content is created mostly in the mobile nodes, e.g. pictures, movies, etc. Differences to traditional CDN Clients are mobile and have unreliable connections Most of the content is produced at the edges In normal operation content is uploaded automatically Service also acts a backup service Sharing (Content Delivery) is enable among users or to everybody

Company Confidential 4 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials Life cycle of a media item Objects are created in the device (e.g. picture) They are automatically uploaded to the service and a unique ID is generated On the service side they are stored and entries into a metadata DB are created Files made public or set as shared can be requested based on the ID (Security restrictions apply) What is the best way to store and distribute those files in a scalable way?

Company Confidential 5 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials Deferred uploading In some cases automatic uploading is not optimal While roaming Low battery situations Very slow connections In those cases media is not uploaded completely: Metadata is sent to the service (Searches are enabled) Possible a low-resolution object is uploaded But we still want to allow for publication

Company Confidential 6 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials Content Delivery Networks Classical client-server architecture (Normally in the form of large clusters) Storage in the form of Storage Area Networks (SAN) or distributed file systems Content Delivery Networks: Complement client-servers for the delivery of static content They are composed of several large clusters distributed globally Each cluster has its own replica stored locally Peer-to-peer CDNs Unstructured networks (Gnutella, BitTorrent) are not adequate for interactive operation But, research structured delivery networks are available Most of them are DHT based Not yet proven as better alternative than existing system

Company Confidential 7 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials Supporting storage systems SANs Well known and robust Expensive to buy and operate Distributed file systems (Google FS) Cheaper Robustness given by software Both are easy to use from the point of view of applications P2P file systems (PAST, Ivy) Require a structured network for reliably locating files Keeping the structure is expensive, especially for mobile devices

Company Confidential 8 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials Architectures Architecture with centralized storage Architecture with P2P storage

Company Confidential 9 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials Issues on current architectures Centralized file systems cannot easily deliver content still in the mobile devices Solutions through e.g. mobile web servers are possible Structured P2P networks create overhead on keeping the structure Direct P2P delivery is not feasible for web based interactive applications

Company Confidential 10 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials Proposal for a hybrid architecture Delivery and queries to/from web based clients are done in the traditional way Use a P2P storage system based on DHT (Like Chord or PAST) Each node has a set of items stored locally and it knows its IDs Make the devices part of the P2P storage system Allows to access item still in the phone This is only used if needed The set of IDs in a node are augment with those of the devices connected to Metadata is still kept centrally to enable queries and use when the device is out of range

Company Confidential 11 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials High-level view

Company Confidential 12 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials Open issues Validate the concept through simulation and/or implementation Are existing DHT-based routing protocols enough to make this workable Creations of metrics to compare different systems Security is an issue since mobile clients become part of the storage system Is it worth the effort? Are there other subsidiary benefits

Company Confidential 13 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials Q&A

Company Confidential 14 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials How to use Nokia core and secondary colors R 235 G 233 B 216 R 230 G 192 B 031 R 000 G 051 B 204 R 068 G 165 B 028 R 175 G 212 B 240 R 206 G 150 B 032 R 175 G 148 B 023 Nokia blueNokia greenNokia secondary blueNokia secondary colors for charts & shapes R 191 G 215 B 218 Nokia secondary color palette (secondary blue, secondary neutrals, secondary brights) can only be used in charts and shapes, in addition to core colors.