Cut-Through Forwarding for CCN Message Fragments
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Solution Overview
Problem
In heterogeneous networks with both CCN and IP nodes, the existing method of IP fragmentation for CCN messages introduces delays due to the need for reassembly and re-fragmentation of packets, which hampers efficient communication.
Innovation Solution
The system pre-fragments CCN messages into smaller packets with a fragment header that includes a flow identifier, fragment count, and index, allowing for cut-through forwarding by mapping flow identifiers to HSVLI and updating the Pending Interest Table, enabling immediate forwarding of fragments without waiting for complete packet arrival.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If IP fragmentation is used for CCN messages in heterogeneous networks, then the messages can be transmitted across networks with different MTU limits, but the transmission delay increases due to reassembly and re-fragmentation operations
Solution Approach 1:
The patent applies preliminary action by performing CCN message fragmentation at the source node before transmission, rather than relying on IP layer fragmentation during transmission. The source node pre-fragments the CCN message into fragments that fit within MTU limits of intermediate networks, and includes a fragment header with flow identifier and fragment number. This eliminates the need for intermediate routers to perform reassembly and re-fragmentation operations, thereby reducing transmission delay while maintaining adaptability across heterogeneous networks with different MTU limits.
2Measurement precision
If CCN routers wait for complete packet arrival to determine next hop, then routing accuracy is improved, but forwarding speed decreases
Solution Approach 1:
The patent applies segmentation by dividing the CCN message into multiple fragments, each with a fragment header containing a flow identifier and fragment number. The fragment header includes the HSVLI (hierarchically structured variable-length identifier) that enables routing decisions. This allows intermediate CCN routers to forward fragments based on the flow identifier without waiting for complete packet arrival, improving forwarding speed while maintaining routing accuracy through the included identifier information.
Solution Approach 2:
The fragment header acts as an intermediary element that carries essential routing information (flow identifier and HSVLI) without requiring the complete CCN message to be present. This intermediary structure enables routers to make forwarding decisions based on the fragment header alone, eliminating the need to wait for complete packet arrival while ensuring accurate routing to the next hop.
3Adaptability or versatility
If IP encapsulation is used to carry CCN messages, then interoperability between CCN and IP networks is improved, but additional processing overhead is introduced
Solution Approach 1:
The patent applies preliminary action by performing CCN message fragmentation at the source node before IP encapsulation, rather than fragmenting after encapsulation. This preliminary fragmentation reduces the size of the IP payload, which in turn reduces the processing overhead for IP encapsulation and decapsulation operations at intermediate nodes. The fragment header with flow identifier enables efficient handling of fragmented CCN messages throughout the IP network.
Data Source
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AI summary
One embodiment provides a system that facilitates cut-through forwarding of message fragments over a network. During operation, the system receives a packet that corresponds to a fragment of a message and contains a fragment header. The system stores in a data structure a mapping relationship between the fragment header and a hierarchically structured variable-length identifier (HSVLI), wherein the HSVLI comprises contiguous name components ordered from a most general level to a most specific level. The system makes a forwarding decision for the packet based on the fragment header prior to receiving all fragment packets associated with the message, thereby facilitating cut-through forwarding of the message fragments over a network.