4. Pseudowire signaling [RFC4447]

In the first part of this dossier, we described the structure of a Pseudowire encapsulation. This encapsulation is based on an MPLS header containing the label that identifies the PW at both PE ends. This label can be statically configured for small networks, but this configuration mode quickly becomes restrictive for larger networks such as that of an operator. In order to facilitate PW maintenance, it is therefore preferable to rely on dynamic mechanisms for announcing the PW label [RFC4447]. This avoids the problems (complexity, configuration errors, etc.) associated with static configuration.