Previous-Hop Decapsulation for GRE Tunnel Bandwidth Optimization
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Solution Overview
Problem
The increased length of GRE-encapsulated packets due to added headers results in higher data traffic and link bandwidth occupancy, leading to increased processing pressure on destination devices and inefficient tunnel operations.
Innovation Solution
Implementing a method where network devices configure forwarding entries based on tunnel notification messages to decapsulate packets at previous-hop devices, reducing the load on destination devices and optimizing bandwidth usage through a tunnel keepalive mechanism that uses keepalive response packets with TTL=1 to notify previous-hop devices for early decapsulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If GRE encapsulation is used to transmit data packets via another network layer protocol, then packet transmission flexibility is improved, but data traffic volume and link bandwidth occupancy increase due to added headers
Solution Approach 1:
The patent extracts the decapsulation function from the destination device and relocates it to the previous-hop device. This removes the unnecessary GRE header processing from the destination device, effectively taking out the bandwidth-wasting encapsulated packets from the link and replacing them with smaller decapsulation notification packets.
Solution Approach 2:
The patent implements preliminary decapsulation at the previous-hop device before packets reach the destination device. The previous-hop device performs decapsulation in advance and sends only the decapsulated inner packets or notification packets to the destination device, preventing the transmission of full GRE-encapsulated packets across the link.
2Adaptability or versatility
If GRE encapsulation is used to transmit data packets via another network layer protocol, then packet transmission flexibility is improved, but processing pressure on destination devices increases
Solution Approach 1:
The patent extracts the decapsulation function from the destination device and relocates it to the previous-hop device. This removes the computationally intensive GRE header parsing and decapsulation operations from the destination device, significantly reducing its processing pressure while maintaining the tunneling capability.
Solution Approach 2:
The patent introduces the previous-hop device as an intermediary that performs decapsulation before forwarding packets to the destination device. This intermediary handles the complex GRE processing, allowing the destination device to receive only simplified inner packets or notification packets, thereby reducing its processing burden.
3Reliability
If decapsulation is performed at destination devices, then packet delivery accuracy is ensured, but tunnel operation efficiency deteriorates due to processing pressure and bandwidth occupancy
Solution Approach 1:
The patent performs decapsulation in advance at the previous-hop device before packets are forwarded to the destination device. This preliminary action ensures that the destination device receives already-decapsulated inner packets, maintaining packet delivery accuracy while dramatically improving tunnel operation efficiency by eliminating redundant processing at the destination.
Solution Approach 2:
The patent segments the decapsulation process from the final packet delivery function. By separating these two functions and placing decapsulation at the previous-hop device, the system maintains reliable packet delivery (the inner packet integrity is preserved) while improving overall tunnel efficiency through distributed processing.
Data Source
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AI summary
A method of forwarding a packet and a network device are provided. According to an example of the method, when serving as a previous-hop device of a destination device of a first tunnel, the network device receives a first notification message from the destination device of the first tunnel, where information relating the first tunnel is carried in the first notification message. The network device configures a forwarding entry, where a match domain of the forwarding entry includes the information relating the first tunnel. After an encapsulated data packet is received, and if the encapsulated data packet matches the forwarding entry, the network device decapsulates the encapsulated data packet and then forwards the decapsulated data packet to the destination device of the first tunnel.