In Rfc3107,Network Layer Reachability Infomation(NRLI) in the Multiprotocol Extensions attribute is encoded as one or more triples of the form .whose fields are described below:
+---------------------------+ | Length (1 octet) | +---------------------------+ | Label (3 octets) | +---------------------------+ ............................. +---------------------------+ | Prefix (variable) | +---------------------------+the Length field indicates the length in bits of the address prefix plus the label(s). But I can not know which bits indicates the length. For Example:I capture a packet,and the network layer reachability information is (in hex):78 00 80 90 00 00 00 01 00 00 00 01
01 01 01 01. 0x78 is the MP reach NLRI prefix length, 0x00 80 90 is MP reach NLRI label stack, 0x00 00 00 01 00 00 00 01is MP reach NLRI Distinguisher, 0x01 01 01 01. is MP reach NLRI IPv4 prefix. 0x78 is 120 in decimal ,but the length is 3+8+4=15,not 120,please tell me which bits indicate the length?