EVPN Multihoming Packet Duplication Prevention via Decapsulation
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Solution Overview
Problem
EVPN multihoming in computer networks leads to packet duplication issues due to redundant connectivity, especially with Broadcast, Unknown unicast, or Multicast (BUM) traffic, which existing solutions like split-horizon and designated forwarder rules struggle to scale effectively as network size increases.
Innovation Solution
A network device with control circuitry that analyzes packets and drops duplicates by checking for decapsulation status instead of remote source IP, reducing the complexity of access control lists and enhancing scalability through rules like BUM && Decap && VID && Egress_Port or BUM && Decap && Egress_Port && (VIDâ„neighbor_SIP).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If split-horizon or designated forwarder rules are used to prevent packet duplication in EVPN multihoming, then packet duplication is reduced, but the number of filter line items in access control lists increases significantly, reducing scalability
Solution Approach 1:
The patent changes the filtering parameter from checking remote source IP addresses to checking the decapsulation status of packets. Instead of maintaining complex ACLs with numerous source IP filters, the solution uses a single decapsulation status check that works across all EVPN multihoming scenarios, thereby preventing packet duplication while maintaining scalability.
2Reliability
If comprehensive filtering rules are implemented to handle all EVPN multihoming scenarios, then packet duplication is prevented, but the filtering process becomes increasingly complex as network size grows
Solution Approach 1:
The patent implements a universal filtering mechanism based on decapsulation status that handles all EVPN multihoming scenarios (active-standby, active-active, single-homing) through a single rule set. This universal approach eliminates the need for scenario-specific filtering rules, maintaining reliability across diverse network configurations while preventing complexity growth.
3Reliability
If multiple filter line items are added to cover all source IPs and VLANs, then packet duplication prevention is improved, but the solution becomes non-scalable for large networks
Solution Approach 1:
The patent extracts the essential filtering criterion from the complex set of source IP and VLAN-based rules, isolating the decapsulation status as the sole determining factor for packet duplication prevention. This extraction reduces the filtering logic from numerous specific rules to a single general rule, enabling scalability while maintaining effective packet duplication prevention.
Data Source
AI summary
One embodiment includes a network device including multiple interfaces to serve as ingress ports for receiving network packets from nodes in remote customer-site network(s) via a tunnel in a provider network, and from nodes in a local customer-site network, and egress ports for forwarding at least some of the network packets, and control circuitry to make a decision to drop a network packet to reduce packet duplication in at least one of the nodes, responsively to the network packet being identified as a packet of broadcast, unknown unicast, or multicast traffic, the network packet being subject to decapsulation of an encapsulation header, being assigned to one of the egress ports, and having a header including one of a plurality of virtual local area network identifications, or one of a plurality of source identifications.