Reading for Lecture Nov 6

Internet Indirection Infrastructure

The i3 architecture aims to ease the process of providing services like mulitcast, anycast and mobility. It offers rendezvous-based communication abstraction. The i3’s level of indirection that decouples the act of sending a packet from the act of receiving the packet allows i3 efficiently support a wide variety of fundamental communication services.

In i3, sources send packets to a logical identifier, and receivers express interest in packets sent to an identifier. The delivery is still best-effort like today’s Internet. The i3’s join operation is inserting a trigger. This operation is more flexible than IP multicast since it allows receivers ro control the routing of the packet.

Each packet in i3 is a pair of (id, data). Receivers use triggers to express their interest in packets. A trigger is of the form (id, addr) indicating that all packets with an identifier id should be forwarded by i3 to the node identified by addr.

Each identifier is mapped to a unique i3 node. When a trigger is inserted, it is stored in the given node. When a packet is sent to the id, it is routed to the node responsible for the id. At there, it is matched against triggers and the packet is forward to all the hosts interested in that packet.

Middleboxes No Longer Considered Harmful

The middleboxes like NATs, firewalls, and transparent caches have become an important part of today’s Internet. The DOA architecture aims at facilitating the deployment of middleboxes while eliminating their dangerous side effects.

The DOA architecture is based on two main ideas: 1) all entities have a globally unique identifier in a flat namespace and packets carry these identifiers. 2) DOA allows senders and receivers to express that one or more intermediaries should process packets en route to a destination.

Each host has an unambiguous endpoint identifier picked from a large namespace. This identifier is required to be independent from network topology. It can also carry cryptographic meaning. To communicate with an end-host identifier, a prospective peer uses the mapping service to resolve the EID to an IP address.

Thus an EID can resolve to another EID, allowing an end-host to map its EID to a delegate’s identity. The DOA obeys the two Internet’s tenet. However, it seems that DOA try to satisfies the two telnets by an explicit delegation mechanism. No middleboxes implicitly interfere with other Internet element’s information.