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Multi-site DCI and anycast gateways

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Walkthrough

Inter-POD L2 via VXLAN stitching

Selective L2 stretch: leaf → local fabric → interconnect gateway stitches EVPN/VXLAN toward the remote POD. Juniper documents global vs translational VNI stitching.

Step 1 / 3
Host A · POD-ALeaf A · VTEPSpine AiGW-A1iGW stitchiGW-A2WAN / DCI underlayDCI underlay IPiGW-B1iGW stitchiGW-B2Spine BLeaf B · VTEPHost B · POD-B

POD-A and POD-B keep local leaf–spine fabrics. Interconnect gateways (iGWs) stitch selected VNIs across the WAN instead of a full leaf-to-leaf mesh between sites.

Roles and CLI follow Juniper NCE/interconnect docs — not a universal vendor default.

Walkthrough

Anycast gateway on local leaves

Hosts ARP a shared anycast gateway IP/MAC; the local leaf answers so first-hop stays on-POD. Juniper documents do-not-advertise patterns to avoid conflicting GW MAC via EVPN.

Step 1 / 3
Host A · POD-ALeaf A · VTEPanycast GW IP/MACSpine AiGW-A1iGW-A2WAN / DCI underlayiGW-B1iGW-B2Spine BLeaf B · VTEPsame anycast GWHost B · POD-B

Edge-routed designs often place the same IRB/VGA IP (and consistent MAC where required) on leaf gateways so every host shares one logical default gateway.

Walkthrough

Single interconnect gateway fails

With redundant all-active iGW peers at a site, losing one gateway keeps stitched paths via the peer. Losing both iGWs isolates that site’s stitched VNIs.

Step 1 / 3
Host A · POD-ALeaf A · VTEPSpine AiGW-A1all-active peeriGW-A2all-active peerWAN / DCI underlayiGW-B1iGW-B2Spine BLeaf B · VTEPHost B · POD-B

POD-A runs iGW-A1 and iGW-A2 as interconnect peers (all-active multihoming / iESI patterns in Juniper interconnect docs).