Gateway L2 Service Node Failover via Heartbeat Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In software-defined networks, detecting failures of layer 2 bump-in-the-wire services and quickly redirecting data messages to backup nodes is challenging due to the difficulty in identifying layer 2 service node failures.
Innovation Solution
Establishing dual connections to layer 2 service nodes with different IP and MAC addresses, using unidirectional broadcast heartbeat signals to detect failures and facilitate failover, and employing active-standby configurations with cluster service nodes to ensure seamless data message redirection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a layer 2 bump-in-the-wire service is inserted in the processing pipeline, then service functionality is provided, but failure detection becomes difficult
Solution Approach 1:
The patent introduces heartbeat messages as an intermediary mechanism to detect service node failures. These special data messages traverse the layer 2 service pipeline and allow the gateway device to determine whether service nodes are operational, thereby solving the difficulty of failure detection in layer 2 bump-in-the-wire services
Solution Approach 2:
The patent implements a feedback mechanism where the gateway device sends heartbeat messages to service nodes and monitors their responses. Based on the absence or presence of responses, the gateway device can detect failures and trigger appropriate actions such as redirecting data messages to backup service nodes
2Reliability
If a backup layer 2 service node is provided, then service continuity is ensured, but redirection time increases
Solution Approach 1:
The patent pre-configures backup service nodes and establishes their readiness in advance. When a failure is detected through heartbeat message monitoring, the gateway device can immediately redirect data messages to the pre-prepared backup node without delay for configuration or setup, thus minimizing redirection time
3Difficulty of detecting and measuring
If dual connections with different IP and MAC addresses are established, then failure detection capability is improved, but device complexity increases
Solution Approach 1:
The patent makes the gateway device's interfaces universal by enabling each interface to serve multiple functions: normal data message forwarding and heartbeat message transmission. This multi-functionality allows failure detection without requiring separate dedicated detection hardware or connections, thereby limiting the increase in device complexity
Data Source
AI summary
Some embodiments provide a method for providing a layer 2 (L2) bump-in-the-wire service at a gateway device (e.g., a layer 3 (L3) gateway device) at the edge of a logical network. The method, in some embodiments, establishes a connection from a first interface of the gateway device to a service node that provides the L2 service. The method also establishes a connection from a second interface of the gateway device to the L2 service node. The method then sends data messages received by the gateway device that require the L2 service to the service node using the first interface. Some embodiments provide a method for applying different policies at the service node for different tenants of a datacenter. Data messages received for a particular tenant that require the L2 service are encapsulated or marked as belonging to the tenant before being sent to the service node. Based on the encapsulation or marking, the service node provides the service according to policies defined for the tenant.