1. Naming for Mobile Systems
Karthik Dantu and Steve Ko

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

3. 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

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

5. 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

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

7. 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

8. 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

9. 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

10. 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

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

12. 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

13. 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

14. 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

15. 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)