wiki:RFC 5492, Capabilities Advertisement with BGP-4

Version 2 (modified by jgs@…, 4 years ago) (diff)


Notes about RFC 5492

  • Section 4 talks about how "BGP speakers MAY include more than one instance of a capability ... with different Capability Value". The historical reason for this is because RFC 4760 specified that the MP-BGP capability be advertised like that, multiple instances of the capability, one for each AFI/SAFI. However, it was the authors' intent to discourage such idioms in the future, preferring to put all necessary data into a single capability as TLVs barring a reason to do otherwise. In any case, people writing documents that introduce new capabilities need to be clear about exactly how their capability is supposed to be formatted – either as TLVs within a single instance of the capability, or as multiple capabilities.