Information About Layer 2 Tunnel Protocol Version 3; L2Tpv3 Operation - Cisco CRS Configuration Manual
Ios xr virtual private network
Hide thumbs
Also See for CRS:
- Configuration manual (430 pages) ,
- User manual (304 pages) ,
- Command reference manual (155 pages)
Table of Contents
Advertisement
Information About Layer 2 Tunnel Protocol Version 3
• You must enable Simple Network Management Protocol (SNMP) notifications of L2TP session up and
A cross-connection is expressed as xconnect in the CLI.
Note
Information About Layer 2 Tunnel Protocol Version 3
To configure the L2TPv3 feature, you should understand the following concepts:
L2TPv3 Operation
The following figure shows how the L2TPv3 feature is used to set up VPNs using Layer 2 tunneling over an
IP network. All traffic between two customer network sites is encapsulated in IP packets carrying L2TP data
messages and sent across an IP network. The backbone routers of the IP network treat the traffic as any other
IP traffic and needn't know anything about the customer networks.
Figure 25: L2TPv3 Operation
In the above figure the PE routers R1 and R2 provide L2TPv3 services. The R1 and R2 routers communicate
with each other using a pseudowire over the IP backbone network through a path comprising the interfaces
int1 and int2, the IP network, and interfaces int3 and int4. The CE routers R3 and R4 communicate through
a pair of cross-connected Ethernet or 802.1q VLAN interfaces using an L2TPv3 session. The L2TPv3 session
tu1 is a pseudowire configured between interface int1 on R1 and interface int4 on R2. Any packet arriving
on interface int1 on R1 is encapsulated and sent through the pseudowire control-channel (tu1) to R2. R2
decapsulates the packet and sends it on interface int4 to R4. When R4 needs to send a packet to R3, the packet
follows the same path in reverse.
Cisco IOS XR Virtual Private Network Configuration Guide for the Cisco CRS Router, Release 6.1.x
146
session down events.
Implementing Layer 2 Tunnel Protocol Version 3
Advertisement
Table of Contents
