Server selection and admission control for IP-based video on demand using available bandwidth estimation

Service providers offering IP-based video on demand services often replicate video content in multiple content servers with different network points of attachment. When a request for a content item arrives from an end-user, a decision must be made as to whether the request should be admitted and, if so, which server should be used. To ensure adequate quality-of service this admission control/server selection decision should be cognisant of the current link utilisation on the paths between the end-user's point of attachment and those of the servers. We have studied the conditions and parameters under which end to-end available bandwidth estimation tools (ABETs) pathChirp and Assolo can be used in this decision process. We specify an admission control/server selection algorithm that uses available bandwidth estimations. Simulation study results show pathChirp (but not Assolo), when appropriately parameterised, can generate available bandwidth estimates that can be used by our admission control/server selection algorithm to react appropriately to changes in background loads on network paths.