<NetworkiNg> (LSR) A device that typically resides somewhere iN the middle of a Network aNd is capable of forwardiNg datagrams based upoN a label. IN maNy cases, especially early versioNs of MPLSNetworks, a LSR will typically be a modified ATMswitch that forwards datagrams based upoN a label iN the VPI/VCI field. (1999-06-14)