VTEP Multipath Forwarding with Direct VM-to-VTEP Mapping
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Solution Overview
Problem
Conventional VTEP data traffic forwarding systems experience issues with traffic tromboning and routing table exhaustion due to the transmission of data traffic to remote VTEP devices not directly connected to the destination virtual machine, requiring an entry for each virtual machine in the ingress VTEP's Longest Prefix Match (LPM) routing table.
Innovation Solution
A VTEP data traffic forwarding system that identifies and associates VTEP device identifiers with directly coupled virtual machines, allowing data traffic provisioning devices to forward traffic directly to the correct VTEP device based on these associations, preventing tromboning and optimizing routing table usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional ECMP routing is used in VTEP devices, then traffic can be distributed across multiple paths, but traffic tromboning occurs when data traffic is transmitted to a remote VTEP device that is not directly connected to the destination virtual machine
Solution Approach 1:
The routing table is segmented into two distinct parts: an ECMP routing table for subnet-level routing and a VTEP-specific routing table for direct virtual machine-to-VTEP mappings. This segmentation allows the system to use the appropriate routing method depending on whether the destination is a subnet or a specific virtual machine, thereby avoiding traffic tromboning while maintaining ECMP benefits for subnet traffic.
Solution Approach 2:
A VTEP-specific routing table acts as an intermediary layer between the ECMP routing table and the actual data traffic forwarding. This intermediary table provides direct VTEP device identifier-to-virtual machine mappings, enabling the system to bypass unnecessary remote VTEP devices and forward traffic directly to the correct destination, thus eliminating traffic tromboning latency.
2Reliability
If exact-match IP address routing entries are provided for each virtual machine in the LPM routing table, then traffic tromboning is avoided, but the routing table is exhausted and scalability is reduced
Solution Approach 1:
The routing functionality is segmented into two separate routing tables: the ECMP routing table maintains subnet-level routes with prefix matching capability, while the VTEP-specific routing table stores direct VTEP device identifier-to-virtual machine mappings. This segmentation allows the system to avoid storing exhaustive virtual machine IP entries in the LPM table while still achieving direct routing for virtual machine traffic.
Solution Approach 2:
The system transitions from traditional IP-address-based routing to a dual-dimensional routing approach: subnet-level routing based on IP prefixes in the ECMP table, and direct routing based on VTEP device identifiers in the VTEP-specific table. This dimensional change enables efficient routing without exhausting the LPM routing table with individual virtual machine entries.
3Adaptability or versatility
If remote VTEP devices are used for virtual machine connectivity, then virtual machines can be accessed across different L2 domains, but routing table exhaustion occurs due to requiring an entry for each virtual machine
Solution Approach 1:
The routing information is segmented into subnet-level routing data in the ECMP table and VTEP-specific mapping data in the VTEP-specific table. This allows cross-L2 domain connectivity to be maintained through subnet routes while VTEP-specific direct mappings are stored separately, avoiding the need to populate the LPM routing table with individual virtual machine entries.
Solution Approach 2:
The VTEP-specific routing table serves multiple functions: it provides direct routing to virtual machines, enables cross-L2 domain connectivity, and prevents routing table exhaustion. By consolidating these functions in a dedicated table with VTEP device identifier-based lookups, the system achieves universal connectivity without proportionally increasing routing table entry quantity in the LPM table.
Data Source
AI summary
A VTEP data traffic forwarding system includes a second VTEP device coupled to a data traffic provisioning device and a first VTEP device. The second VTEP device identifies a virtual machine directly coupled to the first VTEP device, associates a first VTEP device identifier for the first VTEP device in a database with a virtual machine identifier for the virtual machine, and identifies the association of the first VTEP device identifier and the virtual machine identifier to the data traffic provisioning device, with the association of the first VTEP device identifier and the virtual machine identifier causing the data traffic provisioning device to provide the first VTEP device identifier in data traffic destined for the virtual machine. The second VTEP device then receives data traffic including the first VTEP device identifier from the data traffic provisioning device and, in response, forwards the data traffic to the first VTEP device.