- DMVPN Phase 1
- mGRE on Hub and p-pGRE on spokes
- No direct spoke to spoke communication.
- Routing
- Summarization and default at hub is allowed.
- Next-hop on spokes is always changed by the hub.
- mGRE on Hub and p-pGRE on spokes
- DMVPN Phase 2
- mGRE on hub and spokes
- NHRP required for spoke registration to hub.
- NHRP required for spoke to spoke resolution.
- Spoke to spoke tunnel triggered by spoke.
- Routing
- Summarization/default not allowed at hub.
- Next hop on spokes is always preserved by hub.
- Multi-level hierarchy requires hub daisy-chaining.
- mGRE on hub and spokes
- DMVPN Phase 3
- mGRE on hub and spokes.
- NHRP required for spoke registration to hub.
- NHRP required for spoke to spoke resolution.
- When a hub hairpins out same interface:
- Send NHRP redirect message to packet source.
- Forward original packet down to spoke via RIB.
- Routing
- Summarization and default at hub is recommended.
- Results in NHRP routes for spoke to spoke tunnel.
- With no-summary, NHO is performed for spoke to spoke tunnel.
- Next-hop is changed from hub IP to spoke IP.
- Next hop on spokes is always changed by the hub
- NHRP resolution triggered by hub.
- Multi-level hierarchy works without daisy-chaining.
- Summarization and default at hub is recommended.
- mGRE on hub and spokes.
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