Requirement for Analysis of SIP Paths
There is no defined mechanism today by which SIP proxies can insert path related information in a SIP message that is being routed across a network. As an example, a network administrator may want to trace the path as a SIP message traverses across her network to detect failure points. As another example, a user may want to discover capabilities of servers in the path of a call. Although there is an informal mention of using the OPTIONS method to achieve the latter example [1], there is no defined way to achieve the same today.