Enables (true) or disables (false, the default) Traffic Engineering for IPv4 at this level: enabling it requires isisSysLevelMetricStyle be set to wide or both and isisSysTERouterID be configured, after which this router advertises its IPv4 TE router ID and available TE parameters for IPv4-enabled links in its LSPs; this object is ignored entirely if the ipv4 bit isn't set in isisSysProtSupported. An admin enables this when standing up MPLS-TE for IPv4, making sure the prerequisite metric-style and router-ID objects are configured first.