Verifying Network Properties in SRv6 based Service Function Chaining

Abstract

Segment Routing over IPv6 (SRv6) is a simple and scalable protocol for building service function chaining (SFC) on IPv6 data plane. Despite the benefits, managing the data plane of service chains in SRv6 is an error-prone task for network operators, especially in large-scale data center networks. Data plane verification is a promising approach to formally verify the operator requirements. However, the existing approaches do not fully support header modifications with a variable length header in SRv6 and network functions for the service chains. In this paper, we propose a new data plane verification approach for the service chain management. Unlike the existing works, our proposed data plane model for the verification naturally includes header modifications in SRv6 and network functions for the service chains. On the basis of the model, we develop a search-based verification technique for two fundamental network properties: network reachability and isolation of a service chain from the others. To confirm the appropriateness of the approach, we implement a data plane verifier based on the model. Using the verifier, we demonstrate the effectiveness of our approach in two case examples. Through the demonstration, we show that our approach is expressive enough to verify network properties for safely managing the service chains