Phase 2:

When SPOKE wants to communicate with another SPOKE, a dynamic SPOKE to SPOKE tunnel will get created!

CEF table for SPOKE2 from SPOKE1 route will be incomplete and will be in incomplete adjacancy

Therefore the SPOKE1 sends a NHRP request to the HUB and when HUB replies, the SPOKE2 route will become valid

During resolution request, CEF won't be used - Process Switching using Routing table will be used

Routing table will get updated in SPOKE1 and SPOKE2

Temporary/Dynamic Tunnel valid for 2 hours by default!

Phase 3:

Advantages: Summarization can be done in HUB, but in Phase 2 since we preserve the next hop, we cannot do summarization

Problems in Phase 1:

No dynamic SPOKE to SPOKE tunnel

CPU utilization high on HUB

Problems in Phase 2:

No Summarization possible

Until the resolution reply, process switching is used instead of CEF

Therefore in Phase 3, we combine summarization and exclude process switching and form Dynamic Spoke to Spoke Tunnels

CEF Table is valid before resolution and after resolution