5/28/03--chow Concast 1

Concast and Convergent Connection: Many-to-One

Network ServiceC. Edward chow

5/28/03--chow Concast 2

Outline of the Talk

• Definition

• Related Research

• Application Layer Concast

• MPLS Concast?

5/28/03--chow Concast 3

Concast vs. Convergent Connection

• Current IPv4 supports unicast, multicast, broadcast.

• IPv6 supports additional anycast.• Convergent Connection: Multiple Senders one

Receiver, like an Inverse of multicast. – But does not have to be a network layer function. – Can be in Application: Application Layer Concast.– Can be in MPLS: MPLS-based Concast.

• Concast (Defined by the research group at Univ. Kentucky): A convergent connection with single network address represented a group of senders and a network layer service.

5/28/03--chow Concast 4

Concast vs. Multicast

• Protocol design: reduce bandwidth assumption and protocol processing time.

• Avoid implosion—processing a number of incoming packets that grow with the size of the group.

• Concast has a group source address and unicast destination address.

5/28/03--chow Concast 5

Merge Semantics vs. Timing Semantics

• Merge Semantics: What packet is to be delivered to the receiver. (How the router merge the packets? What data fusion operator to use?)– Add (casualty count, vote)– Concatenate (Timestamp, location, temperature)– Mixing (combine four video streams in one)– Filtering/Threshold (when the values exceed

threshold)• Timing Semantics: When is this single packet

delivered to the receiver? – Periodical– Last packet (how to define that?)

5/28/03--chow Concast 6

Potential Concast Applications

• Reliable multicast acknowledgement.

• Distributed monitoring systems

• Load balancing

• Distributed Audio/Video mixing.

5/28/03--chow Concast 7

Simple Concast vs. Custom Concast

• Simple Concast: provide generic– application-independent merge semantics (fuse identical packets

into one copy)– Application-independent timing semantics

(deliver the fused packet as it is the first transmitted copy, e.g. NACK suppression for reliable multicast --- forward the first NACK and discard all other NACKS of the same msg.

• Custom Concast: Allow users to define their own merge and timing semantics by– Downloading code in some form– Selecting them from a predefined set.

• Custom Concast is a perfect justification for active networks.