Contrail: Mobile-to-Mobile Networking over 3G NetworksPatrick Stuedi, Mahesh Balakrishnan, Iqbal Mohomed, Morley Mao,

Venugopalan Ramasubramanian, Ted Wobber,

Chris

Alice

Bob

Jane

“Get status messages from Bob that mention me”

“Get photos of Bob’s dog”

“Get Bob’s location if he’s in Redmond”

Motivation: enable selective sharing of databetween 3G devices

Why not build cloud-based application?PrivacyThe cloud sees (and stores) all your dataEfficiencyAll data is uploaded to the cloud…even if no other device wants it

Cloud-based relayBob uploads matching photos to the cloud which relays them to Alice

Alice BobFilter

Data

Contrail uses two ideas:Edge Filters

Alice installs a filter on Bob requesting all new photos taken in Seattle

In Contrail, the cloud is the routerNo application state or computationCannot view (encrypted) data or filters