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IETF-72 P2PSIP Routing Modes

IETF-72 P2PSIP Routing Modes






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    IETF-72 P2PSIP Routing Modes IETF-72 P2PSIP Routing Modes Presentation Transcript

    • Discussion On Routing Modes IETF72 P2PSIP WG draft-jiang-p2psip-sep-01
      • Jiang XingFeng Jiang.x.f@huawei.com
      • Carlos Macian carlos.macian@upf.edu
      • Victor Pascual victor.pascual@tekelec.com
    • Routing Modes
      • Symmetric Recursive
        • Request and corresponding response follow the same path;
        • Adopted in the current RELOAD draft
      • Direct Response
        • Send response directly back if the requesting peer allows it (e.g. it is publicly reachable)
      • Relay Peer
        • With help from relay peers with unrestricted connections, the response could go through the relay peer to reach the request originator
      • Forward Response
        • Response is considered as a distinct transaction from request and routed through the overlay based on the Node ID of request originator, (i.e. routing based on the underlying P2P algorithm)
      • Iterative
        • where the intermediate peers merely return a response indicating the next hop, but do not actually forward the message to that next hop themselves
    • Why Relay Peer And Direct Response? Improve Success Rate
      • NOT meant to REPLACE symmetric recursive
        • Enhancement to symmetric recursive
        • Could work together with symmetric recursive
      • Main Benefit
        • Reduce the number of hops of response path to
          • Number of hops = 1 - Direct Response
          • Number of hops = 2 - Relay Peer
        • Improve success rate of P2PSIP transaction
    • Where Is Relay/Direct Response Helpful? Dynamic Scenarios
      • Concerns about routing in P2P systems
        • Node’s stability
        • Connectivity stability between peers
      • Where Symmetric MAY NOT Work Well
        • Heavy churn
        • Path with larger hop count
          • The number of hops often follows a uniform distribution within [0, M]; M: lookup complexity of the specific algorithm in use
          • Symmetric works well with smaller hop count
        • Stability of TURN peers has an impact on the connectivity stability between peers
        • Overlays with large scales, for example, over 1000 peers
    • How Relay Peer Works - 1 A B C D Z X Y Request Originator Intermediate Peer Destination Peer Relay Peer Pre-established connection 1 2 3 4 5 5 5 6 7 8 Request Symmetric Recursive Relay Peer
    • How Relay Peer Works - 2
      • A typical message sequence
        • Originator discovers relay peers first
        • Originator carries info about relay peers in the request to be routed around the overlay
        • Destination peer sends the responses to the relay peers which forwards the response toward the request originator
      • When Relay Peer is triggered
        • The destination peer decides whether or not Relay Peer is used
        • Possible criteria
          • The request has traversed so many hops that it is highly probable that one of reverse connections broke down
    • Concerns – Relay Peer
      • Relay Peer
        • Considered as a kind of service, just like STUN/TURN service;
        • Unrestricted connection – Identify Relay Peer
          • Possible to decide whether a peer is on the public Internet in P2PSIP, for example, with the help from bootstrap peer or enrollment server who are already on public Internet;
          • While being on the public Internet, a peer can use Direct Response to determine whether or not it is behind a firewall or address-independent firewall;
    • Concerns – DoS Attack
      • Attack 1
        • A large number of responses are sent to the Relay peer to overload the Relay peer
          • Relay peer only forwards response to the peer with whom (peer) it has direct connections;
      • Attack 2
        • Malicious peers send a great number of requests and indicate to use a Relay Peer to route responses besides using symmetric recursive routing , which will amplify the number of the response to the request originator
          • Destination peer will base response on some criteria treated as a parameter, such as total hops the request’s traversed, to decide whether relay peers are used to route the response;
          • This mitigates the impact from the response amplification
    • Next Step
        • Adopted as a WG item (Direct Response and Relay Peer)?
      • Or
        • The choice of Routing modes be a open issue and need more investigation? (including symmetric recursive)