mplsTunnelARHopIpv4PrefixLen 1.3.6.1.4.1.11.2.3.7.11.12.2.15.15.3.2.7.1.5

If mplsTunnelARHopAddrType is ipV4(1), then the prefix length for this hop's IPv4 address is contained herein. This object is otherwise insignificant and should contain a value of 0.