Restrictions For L2Vpn; Standards And Rfcs - Cisco 10000-2P2-2DC Software Configuration Manual

Chapter 20 Configuring L2 Virtual Private Networks

Restrictions for L2VPN

The L2VPN feature has the following restrictions:
•
•
•

Standards and RFCs

L2VPN conforms to the industry standards and RFCs listed in
Table 20-2
Standard or RFC
draft-martini-l2circuit-trans-mpls-08.txt
draft-martini-l2circuit-encap-mpls-04.txt
RFC 3032
RFC 3036
OL-2226-23
Address format: Configure the LDP router ID on all PE routers to be a loopback address with a
/32 mask. Otherwise, some configurations might not function properly.
The size of maximum transmission unit (MTU) must be the same at both ends of the circuit. To
avoid fragmentation of the packets along the way, ensure that the size of MTU at both end of the
circuit is smaller than the size of MTU in the core.
The following L2VPN features are not supported:
– ATM cell switching of any kind
ATM AAL5 PDU mode
–
Fragmentation and reassembly, as defined in "PWE3 Fragmentation and Reassembly,"
–
draft-ietf-pwe3-fragmentation-05.txt, February 2004
– Sequence number support in the control word
Tunnel stitching
–
Pseudowire termination
–
Standards and RFCs Supported by L2VPN
Table 20-2.
Title
Transport of Layer 2 Frames over MPLS
Encapsulation Methods for Transport of Layer 2
Frames over MPLS
MPLS Label Stack Encoding
LDP Specification
Cisco 10000 Series Router Software Configuration Guide
Restrictions for L2VPN
20-5