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LISP usage for DC migration

Patrice BellagambaMax Ardica

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Enable LISP for Migration

Using ASR1K as PxTRNo modification of existing DCNeed LISP PxTR in the flow

Using Nexus 7K ETR with MobilityLISP ETR (using M1-32) can be either at aggregation or in Octopus

PxTR

ETR

MS/MR

Brownfield DC Greenfield DC

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Control-plane event

/32

PiTR cache:10.17.0.0/24 send map-request10.17.0.0/24 forward-native10.17.0.0/28 forward-native10.17.0.31/32 complete

ETR dyn EID cache:10.17.0.31 Vlan1300

MS cache:10.17.0.0/2410.17.0.31/32

‘Send-map request’ is data-plane driven and triggers after ‘forward-native’ times out every 30s

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Packet flow for North-West1. Ingress flow is tunnelled by

PiTR toward Greenfield2. Return flow is in clear,

using IP path

Asymetric flow (ingress LISP, egress IP) is optimal if no Firewall between WAN edge & PiTR)

PxTR

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Packet flow for North-West

PeTR

Existance of a Firewall between WAN edge & PxTR requires symatrical flow

Use PeTR

PeTR allows return flow to go thru LISP Path, nevertheless it requires ETR to work with default routing

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Packet flow for West-EastNeed a /32 (today manually) to enable 1. proxy-ARP2. Inter-subnet routing

Still option of return traffic using PeTR

Need a /32

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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

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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