I85PREP
⌘ K
Nokia VPRN study materials
Nokia VPRN study resources

Nokia VPRN: Data Center Gateway with VPRN and EVPN

Nokia VPRN · Work through your exam, one topic at a time.

All guide sections

Data Center Gateway with VPRN and EVPN

What this domain tests

The data center gateway domain tests how a Nokia SR OS VPRN connects an EVPN-VXLAN data center fabric to the IP/MPLS WAN. Expect EVPN route types, VXLAN termination, symmetric IRB, and route-target design.

Core rules

  • The DC gateway VPRN terminates VXLAN tunnels and peers BGP-EVPN with leaf switches; the same VPRN can also have WAN interfaces and MP-BGP VPNv4/v6 sessions.
  • EVPN type-2 routes carry MAC/IP reachability; type-5 routes carry IP prefixes. A gateway may use type-5 for prefix advertisement and type-2 for host routes.
  • Symmetric IRB uses an L3 VNI and a shared route-target so traffic is routed on both ingress and egress gateways.
  • Anycast gateway uses the same IP and MAC on multiple leaves or gateways, with EVPN synchronization.
  • MTU must account for VXLAN encapsulation; under-sized core MTU causes silent drops for large flows.

Worked example

A tenant VPRN on the DC gateway has VXLAN VNI 10000 and import/export RT 65000:10000. Leaf1 advertises 10.20.0.0/24 as an EVPN type-5 route with that RT. The gateway imports it, installs it in the VPRN, and re-advertises it as a VPNv4 route to the WAN with the WAN RT. Return traffic from the WAN follows the same VRF and VNI mapping.

Traps

Mismatched RTs between EVPN and VPNv4 silently break the stitch. Asymmetric IRB designs can work but require careful routing; symmetric IRB is easier to scale. Forgetting VXLAN overhead in MTU planning is a common failure.