A network device performs ingress based headroom buffering. The network device may be configured as an output queue switch and include a main packet buffer that stores packet data according to a destination egress port. The network device may implement one or more ingress buffers associated with ingress data ports in the network device. The ingress buffers may be separate from the main packet buffer. The network device may identify a flow control condition triggered by an ingress data port, such as when an amount of data stored in the main packet buffer received through the ingress data port exceeds a fill threshold. In response, the network device may send a flow control message to a link partner to cease sending network traffic through the ingress data port. The network device may store in-flight data from the link partner in an ingress buffer instead of the main packet buffer.