IP reassembly on an L2TP connection

You can now configure the service interfaces on routers to support inline IP packet reassembly on a Layer 2 Tunneling Protocol (L2TP) connection. The IP packet is fragmented over an L2TP connection when the packet size exceeds the maximum transmission unit (MTU) defined for the connection. Depending on the direction of the traffic flow, the fragmentation can occur either at the L2TP access concentrator (LAC) or at the L2TP network server (LNS),and reassembly occurs at the peer interface. (In an L2TP connection, a LAC is a peer interface for the LNS and vice versa.) You can configure the service interfaces on the LAC or on the LNS to reassemble the fragmented packets inline before they can be further processed on the network. On a router running Junos OS, a service set is used to define the reassembly rules on the service interface. The service set is then assigned to the L2TP service at the [edit services l2tp] hierarchy level to configure IP reassembly for L2TP fragments. You can view the reassembly statistics by using the show services inline ip-reassembly statistics <fpc fpc-slot | pfe pfe-slot> command.