4A0-D01: Nokia Data Center Fabric Fundamentals

An IP-VRF is a Layer 3 routing instance with separate route tables and a FIB. A shared Layer 2 subnet or broadcast domain is implemented by a mac-vrf, which can be associated with an IP-VRF through an IRB interface; an IP-VRF alone does not provide the shared-subnet connectivity described.

A configured next-hop group can be referenced by multiple static routes. SR Linux next-hop groups can contain one or more next hops, and referenced static routes use the group’s forwarding or blackhole behavior.

A MAC entry of type duplicate is created when the MAC moves across interfaces more times than the configured threshold during the configured monitoring window. The duplicate entry retains a learned destination, but that destination does not make the MAC a statically configured MAC on the interface. Static MACs are a separate bridge-table entry type.

BGP does not automatically discover neighboring BGP speakers. Peering is established through explicit configuration, including the neighbor address and autonomous system details. Its maturity, dual IPv4/IPv6 support, and scalable control-plane characteristics are valid reasons it is commonly used in data-center networks.

Leaf routers normally peer with spine routers, not directly with other leaf routers. Locally connected server prefixes are advertised from each leaf to the spines, and the spines re-advertise those routes to other leaves; thus, remote server prefixes are learned through the spine layer.