Naming for Mobile Systems Karthik Dantu and Steve Ko

Administrivia “Embedded Android”, now available via library.buffalo.edu Friday project meetings Record/Replay Latency Measurement End-End Connectivity

Naming Systems What is Naming? Examples DNS/IP Address/MAC Address CDNs e.g., Akamai Filesystem Phone Book Features Map known information to required information Ease of registration/use

Intentional Naming System Naming System for Wireless/Mobile World Challenges Resource/Service Mobility Client Mobility Essential Features Expressiveness Responsiveness Robustness Easy Configuration

INS: Features Naming based on Intent as opposed to location Architecture uses what service as opposed to where to find it Clients request a service without listing end nodes – level of indirection Integrates name resolution and message routing Binding at message delivery time Binding/message routing is best effort Message routing Intentional anycast Intentional multicast Runs on top of IP on an overlay network

INS Architecture Overlay of Intent Name Resolvers (INRs) Clients can use network or intent naming Name-specifiers: Hierarchical attribute-value pairs

Name Discovery INRs form overlay network Replicate information via periodic and triggered updates Services disseminate information via soft state Clients request service via name discovery msg Updates Network address Application adv metric Next Hop INR Unique AnnouncerID

Name Lookup Name Record: List of IP addresses of the destinations with next hop info Name Tree: Super-position of all name specifiers with app-specific metrics

Name Lookup LOOKUP_NAME Algorithm: Search for sub-tree that corresponds to the requested name-specifier Returns name-record with all such sub-trees Domain Space Resolver to track all active INRs

Unmanaged Internet Architecture (UIA) Motivation Provide secure peer-peer access for personal/social groups independent of different forms of network connectivity Simplify naming in such personal groups Provide robust connectivity independent of infrastructure Challenges Mobility Scalability Dynamics

UIA: Device Introduction Simple multiple choice device introduction Handshake puts devices in same personal group Devices gossip amongst each other to discover other devices

Group Management Owned by one or more members, or by another group Ownership is transitive Ownership disputes resolved by putting disputing parties in two separate (new) groups, and revoking access to previously accessible groups EID: Endpoint Identifiers are cryptographically unique IDs for devices Name resolution resolves to EIDs Separate EIDs for every user on every device

Naming Principles Resolved right to left Phone.Alice New additions appear as sub-groups E.g., If Alice added Bob, Bob’s root group appears as a sub-group, and vice-versa Can be circular e.g., Phone.Bob.Alice Label conflicts: Resolution does not work until conflict is fixed

Naming Management UIA uses log records Four types of records Create: Initiate a new series Link: Attach a human-readable label to EID/Series ID Merge: Join two series to form a single group. Requires ownership or permission from both owners Cancel: Nullifies a record Example Phone: Create Laptop: Create Phone: Merge Alice: Merge

Overlay Network UIA builds an overlay network for connectivity To reach an EID, it floods the network Each device maintains up to a set number of connections with its peers Peer connections picked according to stability and friendship distance Maintains list of potential peers – initialized by gossiping Token-limited flooding (instead of hop count) Overlay has highly non-uniform degree Not much point searching all devices in given network Location request = (EID, IP,port list of devices traversed)