DNS Extensions for Explicit Service Function Chaining
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current service function chaining approaches within a single administrative domain often result in suboptimal network paths due to lack of end-to-end visibility and control, leading to unsatisfactory user experiences, particularly in terms of network delays.
Innovation Solution
A method and apparatus for service function chaining that performs an address resolution process using a sequence of DNS queries to authoritative name servers, translating service function names into IP addresses, enabling the selection of optimal service instances based on predefined criteria and applying shortest path algorithms to determine the most efficient network path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If service function chaining is enforced by ISP/content provider within a single administrative domain, then service function chain can be established, but network path optimality deteriorates due to lack of end-to-end visibility
Solution Approach 1:
The DNS system is extended to perform multiple functions: traditional domain name resolution and service function chain resolution. The DNS server acts as both a conventional name resolver and an SFC path optimizer, enabling end-to-end visibility and optimal path selection across multiple administrative domains without requiring domain-specific protocols
Solution Approach 2:
The DNS server serves as an intermediary between the client and the service function chain elements. It receives the client's domain name query, resolves the optimal SFC path considering end-to-end network conditions, and returns both the domain IP address and the optimized service function chain path, thereby mediating between naming and routing functions
2Ease of operation
If client resolves entire service function chain on its own, then address resolution can be performed, but network path optimality deteriorates due to lack of global network knowledge
Solution Approach 1:
The client initiates the resolution process by sending a DNS query for the domain name, and the DNS server autonomously performs the service function chain resolution without requiring client-side implementation of complex SFC algorithms. The client simply receives the optimized path information in the DNS response
Solution Approach 2:
The DNS server pre-computes and caches the optimal service function chain paths based on current network conditions and service function availability. When a DNS query is received, the server retrieves the pre-computed optimal path information and includes it in the response, avoiding real-time computation delays
3Adaptability or versatility
If each hop resolves the respective next hop of the service function chain, then distributed address resolution is achieved, but network path optimality deteriorates due to greedy local decisions
Solution Approach 1:
Instead of each hop independently resolving the next hop (greedy approach), the DNS server performs the reverse: it resolves the entire service function chain path from the destination back to the source in a single centralized operation, then returns the complete optimized path to the client, inverting the traditional distributed resolution paradigm
Data Source
AI summary
A method for service function chaining within an end-to-end path of a network connection between a source and destination node includes: executing, for a defined service function chain including an ordered sequence of network service functions, an address resolution process that translates names of the network service functions of the defined service function chain into their corresponding IP addresses. The address resolution process is performed at a name server of the destination node by a sequence of name server queries sent in succession to respective name servers of each of the selected network service functions of the defined service function chain in accordance with their order. Each of the name server queries is answered by a response from a name server of the respective network service function that includes IP addresses of selected instances of a respective network service function chosen by the respective name server according to predefined criteria.