Cisco IOS Wide-Area Networking Configuration Guide - Free Books

• FRF.9 process switched payload compression is not supported.• IETF encapsulation must be used with FRF.9.• FRF.16 is supported only between the CE and the PE routers.• HDLC restrictions for protocol demultiplexing:– IP must be enabled on the interface if you want to configure protocol demultiplexing using thexconnect command.– IPv6 cannot be enabled on the interface at the same time as the xconnect command (with orwithout protocol demultiplexing).– Payload compression is not supported.• Cisco 12000 series router restrictions for protocol demultiplexing:– If a Cisco 12000 series router is acting as the PE with IPv6 protocol demultiplexing using PPP,the remote PE must also be a Cisco 12000 series router.– IPv6 protocol demultiplexing for Ethernet encapsulation on Engine-5 line cards is onlysupported with Version-2 Ethernet SPAs. It is not supported with Version-1 Ethernet SPAs.– IPv6 protocol demultiplexing is not supported on the SIP-400 Engine-3 line card.• IPv6 protocol demultiplexing with PPP encapsulation must be configured in the following order toensure a working tunnel session:1. Configure the IP address on the interface.2. Enter the encapsulation PPP command.3. Enter the PPP ipv6cp id proxy command.4. Enter the xconnect command with the match protocol ipv6 command.If this configuration order is not followed, the tunnel session cannot operate until you issue ashut/no shut command on the protocol demultiplexing interface or do an OIR.L2TPv3 Control Message Hashing Restrictions• L2TPv3 control channel authentication configured with the digest command requires bidirectionalconfiguration on the peer routers, and a shared secret must be configured on the communicatingnodes.• See Table 8 for a compatibility matrix of all the L2TPv3 authentication methods available inCisco IOS Release 12.0(29)S and Cisco IOS Release 12.2(27)SBC and later releases.L2TPv3 Digest Secret Graceful Switchover Restrictions• This feature works only with authentication passwords configured using the L2TPv3 ControlMessage Hashing feature. L2TPv3 control channel authentication passwords configured with theolder, CHAP-like authentication system cannot be updated without tearing down L2TPv3 tunnelsand sessions.• In Cisco IOS Release 12.0(30)S, a maximum of two passwords can be configured simultaneouslyusing the digest secret command.25