1. LISP usage for DC migration
Patrice Bellagamba
Max Ardica

2. Enable LISP for Migration
PxTR
MS/MR
ETR
Using ASR1K as PxTR
No modification of existing DC
Need LISP PxTR in the flow
Using Nexus 7K ETR with Mobility
LISP ETR (using M1-32) can be either at aggregation or in Octopus
Brownfield DC
Greenfield DC

3. Control-plane event
MS cache:
/24
/32
PiTR cache:
/24 send map-request
/24 forward-native
/28 forward-native
/32 complete
ETR dyn EID cache:
Vlan1300
/32
‘Send-map request’ is data-plane driven and triggers after ‘forward-native’ times out every 30s

4. Packet flow for North-West
Ingress flow is tunnelled by PiTR toward Greenfield
Return flow is in clear, using IP path
PxTR
Asymetric flow (ingress LISP, egress IP) is optimal if no Firewall between WAN edge & PiTR)

5. Packet flow for North-West
Existance of a Firewall between WAN edge & PxTR requires symatrical flow
 Use PeTR
PeTR
PeTR allows return flow to go thru LISP Path, nevertheless it requires ETR to work with default routing

6. Packet flow for West-East
Need a /32 (today manually) to enable
proxy-ARP
Inter-subnet routing
Still option of return traffic using PeTR
Need a /32

7. Convergence testing Any failure on Browfield (PxTR side) is sub-second
Failure on Greenfield (ETR with mobility side):
If no default routing
Sub second convergence
But vPC peer-link failure (requires EEM script to get sub-second)
If default routing:
Requires RLOC Probing per EID  60s

8. Caveat PxTR is not (yet?) advertizing map-cache entries to routing
Moved VM is not know in Brownfield
Requires a manual /32
Route watch is not working with default routing
But there is always in general a default route
RLOC probing is per EID (scale ?) and slow (60s)
LSB bits is not working with Nexus 7K
vPC peer-link failure is not handled well
Workaround using script
Globally the solution works well and is deployable