DC-LDP sends label mappings to all upstream peers. Sometimes, due to a change of next hop from IP Routing or a new address from the peer, a peer may change from being upstream to being a downstream peer. This results in the label we sent to the peer no longer being necessary. When set to 'false', these labels are retained (if liberal retention) or released (if conservative retention) by the peer. This is generally desirable, since it has no impact on the data plane and reduces the work for the control plane when a new peer is created. When set to 'true', these labels will be withdrawn when DC-LDP detects the condition. This is sometimes desirable when a network operator requires consistency between labels distributed and labels programmed to the data plane, but cannot use conservative retention mode. This field can be changed at any time, but if changed to 'true' it will only apply to new sessions.