Segment Routing Packet Processing Priority for Loop Prevention
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Solution Overview
Problem
Segment routing standards fail to specify the priority of processing between ultimate segment decapsulation (USD) and ultimate segment pop (USP) when both are set in a packet, leading to inefficient use of computing and networking resources and potential forwarding loops.
Innovation Solution
A network device determines the priority of processing between USD and USP by examining the next header of a packet, discarding packets that cannot undergo USP processing and decapsulating or popping headers as necessary to prevent loops, thereby conserving resources and ensuring correct routing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If segment routing standards do not specify processing priority between USD and USP, then the system maintains flexibility in implementation, but computing and networking resources are wasted due to inefficient processing and potential forwarding loops
Solution Approach 1:
The patent applies preliminary action by establishing processing priority rules before packets are forwarded. The network device determines whether USD or USP should be processed first based on predefined criteria (such as packet type or routing requirements) before actual processing occurs. This prevents forwarding loops and inefficient resource usage by resolving the processing order in advance, rather than dealing with the consequences of ambiguous priorities later.
2Device complexity
If packets are processed without determining processing priority, then processing is simpler, but forwarding loops occur and resources are consumed inefficiently
Solution Approach 1:
The network device performs preliminary determination of processing priority by examining packet characteristics (such as whether it is a reduced mode packet) before executing USD or USP processing. This preliminary step establishes the correct processing sequence in advance, ensuring reliable packet handling and preventing forwarding loops without significantly increasing overall system complexity.
3Reliability
If all packets undergo both USD and USP processing, then all packets are correctly routed, but computing resources are wasted on packets that cannot undergo certain processing
Solution Approach 1:
The patent applies partial action by selectively applying USD or USP processing only to packets that require it. The network device determines whether a packet is a reduced mode packet and applies only the appropriate processing (either USD or USP, but not both), avoiding wasted computation on packets that cannot undergo certain processing while ensuring correct routing for all packets.
4Speed
If processing priority is not determined, then packet handling is faster, but temporary loops are created and network performance deteriorates
Solution Approach 1:
The network device performs rapid preliminary determination of processing priority by checking packet characteristics (such as next header type and reduced mode status) before processing. This quick assessment establishes the correct processing sequence in advance, preventing forwarding loops and ensuring optimal network performance without significantly impacting packet handling speed.
Data Source
AI summary
A network device may receive a packet and may determine whether a next header of the packet is an Internet protocol (IP) header, an Internet control message protocol (ICMP) header, or a segment routing header. The network device may determine, when the next header of the packet is the IP header, whether policy processing of the packet is set to ultimate segment decapsulation and may discard the packet when the policy processing of the packet is not set to ultimate segment decapsulation. The network device may decapsulate an outer header of the packet when the policy processing of the packet is set to ultimate segment decapsulation and may process the packet after decapsulating the outer header of the packet, to generate a processed packet. The network device may forward the processed packet toward a destination.