Cisco IOS Wide-Area Networking Configuration Guide - Free Books

Frame Relay-Specific Restrictions• Frame Relay per-DLCI forwarding and port-to-port trunking are mutually exclusive. L2TPv3 doesnot support the use of both on the same interface at the same time.• The xconnect command is not supported on Frame Relay interfaces directly. For Frame Relay,xconnect is applied under the connect command specifying the DLCI to be used.• Changing the encapsulation type on any interface removes any existing xconnect command appliedto that interface.• To use DCE or a Network-to-Network Interface (NNI) on a Frame Relay port, you must configurethe frame-relay switching command.• The configuration of an L2TPv3 session on a Multilink Frame Relay (MLFR) bundle interface issupported only on Cisco 12000 series 2-port channelized OC-3/STM-1 (DS1/E1) and 6-portChannelized T3 (T1) line cards. (For more information, see Binding L2TPv3 Sessions to MultilinkFrame Relay Interfaces, page 43.)• Frame Relay policing is nondistributed on the Cisco 7500 series. By configuring Frame Relaypolicing, you cause traffic on the affected PVCs to be sent to the RSP for processing.• Frame Relay support is for 10-bit DLCI addresses. Frame Relay Extended Addressing is notsupported.• Multipoint DLCI is not supported.• The keepalive is automatically disabled on interfaces that have an xconnect applied to them, exceptfor Frame Relay encapsulation, which is a requirement for LMI.• Static L2TPv3 sessions do not support Frame Relay LMI interworking.VLAN-Specific Restrictions• A PE router is responsible only for static VLAN membership entries that are manually configuredon the router. Dynamic VLAN membership entries, entry aging, and membership discovery are notsupported.• Implicit tagging for VLAN membership operating on the other layers (such as at Layer 2,membership by MAC address or protocol type, at Layer 3, or membership by IP subnet) is notsupported.• Point-to-multipoint and multipoint-to-point configurations are not supported. There is a 1:1relationship between an attachment circuit and an L2TPv3 session.ATM VP Mode Single Cell Relay over L2TPv3 Restrictions• The ATM VP Mode Single Cell Relay over L2TPv3 feature is supported only on the Cisco 7200 andCisco 7500 series routers with ATM Deluxe PA-A3 interfaces.• After the ATM VP Mode Single Cell Relay feature is configured for a virtual path connection(VPC), no other permanent virtual circuits (PVCs) are allowed for the same virtual path identifier(VPI).23