This object indicates the address type of the link where the
preemption occurs - another, higher priority LSP is being
admitted on this link and there is not enough bandwidth for it
causing this LSP to be preempted (removed) from this link:
- unknown: the object cmplsTunnelPreemptionLinkAddr does not
contain any address
- ipv4: the object cmplsTunnelPreemptionLinkAddr contains
the IPv4 address
- ipv6: the object cmplsTunnelPreemptionLinkAddr contains
the IPv6 address