| 摘要 |
A Software Defined Network (SDN) 108, for use in a communication network 1, acts as an entity in a first service chain of entities through which a data flow is routable by another SDN 104 in the communication network 1. The first service chain comprises one or more service applications 106a, 106b each for performing a service on data from the data flow at a logical layer (e.g. Layer 2 (Data-Link Layer), Layer 3 (Network Layer) or Layer 4 (Transport Layer)) in the communication network 1 associated with that service application 106a, 106b. The SDN 108 routes data from the data flow received at the SDN 108 through a second service chain comprising one or more SDN service applications 110a, 110b, 110c. An SDN service application 110a, 110b, 110c of the second service chain is for performing a service on data from the data flow at a higher logical layer (e.g. Layer 7 (Application Layer)) within the communication network 1 than is a service application 106a, 106b of the first service chain. |
