In a centrally-routed bridging (CRB) fabric the access switches only bridge; all Layer-3 first-hop gateway interfaces (SVIs/IRB) reside on the centralized VTEPs in the distribution (or core) tier.

Edge-routed bridging (ERB) moves both the VTEP and the SVI/IRB to the access leaf switches so that routing is performed at the edge. Therefore, when migrating from CRB to ERB, the default-gateway for every VLAN is relocated from the distribution layer to the access layer.

A. from access to distribution – CRB→ERB moves gateway toward the edge, not toward the distribution layer.

B. from distribution to core – Gateway already central; ERB does not push it further inward.

D. from core to distribution – Still centralised; ERB explicitly places gateway on edge access switches.

1. Juniper Networks, “EVPN-VXLAN Campus Fabric Design Guide,” Rev. 2023-04, Section “CRB vs. ERB,” pp. 7-10.

2. Juniper TechLibrary, “Understanding Campus Fabric Edge-Routed Bridging,” Junos OS Documentation, §‘First-hop gateway location’.

3. Juniper Day One Guide “Deploying Campus Fabrics with EVPN-VXLAN,” Ch. 2, pp. 18-21 (“In ERB the IRB interface is instantiated on the access-layer switch, unlike CRB where it is on the distribution/core device”).