1. Peer-to-Peer Protocol (P2PP)
Binary-based, type-length-value (TLV) objects
No DHT specific detail
Simple state-machine
each request generates a response
Request routing
recursive vs. iterative
parallel requests
Transport
TCP vs. UDP
links between peers
API
Transport
-tradeoffs between the use of TCP and UDP for recursive and iterative routing
-TCP or UDP for overlay maintenance

2. P2PP Functionality
DHT commonalities, performance enhancements are incorporated in the protocol
Capabilities (such as b/w, connection state) exchange
Logical separation for
overlay maintenance
resource manipulation
diagnostics
Overlay maintenance
join, leave, keep-alive, routing-peer-lookup, replicate, update, query
Resource manipulation
insert, lookup, remove
Connection state: behind a NAT or a firewall

3. To SIP or not to SIP
SIP guidelines document allows to register AOR but not a service
STUN or TURN service
Bandwidth estimation service
Overlay maintenance is an active operation
Nodes come and go
Routing-neighbor information needs to be exchanged
SIP is not a distributed system maintenance protocol
Overloading meaning of SIP headers is not a good practice

4. Definitions Resource vs. service Peer vs. client
There is no difference between resource and a service.
What can be a better name for client?