OpenFlow Switch Packet Ingress Tagging for Logical Flow Scalability
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Solution Overview
Problem
Conventional OpenFlow switch settings that prevent packets from being output via their ingress port do not scale well in traffic scenarios with multiple logical flow entities, requiring excessive definition of sub-groups and flow entries, limiting the allocation of logical flow entities to a single port.
Innovation Solution
A method for packet ingress and egress processing in an OpenFlow switch that involves tagging metadata with identifiers for logical flow entities, allowing for efficient handling and separation of packets based on these identifiers, enabling multiple logical flow entities to be allocated to a single port without the need for extensive sub-group and flow table definitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the pre-configured OF setting prevents packets from being output via their ingress port, then packet forwarding control is simplified, but the system cannot scale to handle multiple logical flow entities allocated to the same port
Solution Approach 1:
The patent segments the ingress port into multiple logical flow entities by introducing a flow entity identifier (FEI) that distinguishes different logical flows within the same physical port. This segmentation allows packets from different logical flow entities to be handled differently even though they enter through the same physical port, thus enabling multiple logical flow entities to be allocated to a single port while maintaining simplified forwarding control through the ingress port identifier.
Solution Approach 2:
The patent introduces an intermediary mechanism (the flow entity identifier and associated metadata tagging) between the ingress port and the packet forwarding decision process. This intermediary allows the system to track and control packets based on their logical flow entity origin without complicating the basic ingress port forwarding control, thus resolving the contradiction between simplified control and scalable allocation.
2Ease of operation
If an extra group table is written and set up to include a dedicated output action for the ingress port, then packets can be output via their ingress port, but the number of required sub-groups and flow entries increases exponentially to 2N for N logical flow entities
Solution Approach 1:
The patent makes the group table universal by introducing a flow entity identifier that can be used across all group entries. Instead of creating separate group tables or sub-groups for each logical flow entity, the same group table can handle multiple logical flow entities by matching on the FEI. This allows a single group entry to serve multiple logical flow entities, reducing the exponential growth of flow entries to a linear scale.
Solution Approach 2:
The patent changes the matching parameter from just ingress port identifier to a combination of ingress port identifier and flow entity identifier. This parameter change allows the system to distinguish between different logical flow entities without creating separate group tables, thus reducing the number of required flow entries while maintaining the ability to control packet output for each logical flow entity independently.
3Adaptability or versatility
If N logical flow entities are allocated to a single OF port, then flow level isolation and service emulation are enabled, but the pre-configured OF setting prevents packets from being forwarded between logical flow entities on the same port
Solution Approach 1:
The patent segments the packet forwarding control by introducing flow entity identifiers that distinguish different logical flow entities within the same physical port. This segmentation enables flow level isolation by allowing the system to identify and control packets based on their logical flow entity origin, while still permitting controlled forwarding between logical flow entities through the group table mechanism that matches on FEI.
Solution Approach 2:
The patent introduces dynamic control over packet forwarding between logical flow entities by using the group table with flow entity identifier matching. Instead of a static pre-configured setting that either allows or blocks all ingress port output, the system dynamically controls forwarding based on the specific flow entity identifiers, enabling flexible service emulation and flow isolation while maintaining ease of operation through centralized group table management.
Data Source
AI summary
A technique for packet ingress processing and packet egress processing in an OpenFlow, OF, switch is presented. A method aspect directed to packet ingress processing comprises receiving a packet at an OF port. The packet is associated with one of multiple logical flow entities, such as logical ports, allocated to the OF port. In a next step, the logical flow entity associated with the received packet is determined. Then, metadata for the packet is tagged with an identifier for the logical flow entity associated with the packet. The tagging controls handling of the packet at egress processing. The packet handling, in turn, may include a selective dropping or passing of the packet.