Cisco ASR 9000 Series Configuration Manuallines page 252

Implementing Multipoint Layer 2 Services
GRE Deployment Scenarios
Figure 31: GRE tunnel configured between PE to PE routers
Figure 32: GRE tunnel configured between P to P routers
Figure 33: GRE tunnel configured between P to PE routers
Note
These deployment scenarios are applicable to VPWS and VPLS.
L2VPN and Ethernet Services Configuration Guide for Cisco ASR 9000 Series Routers, IOS XR Release 6.3.x
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