NEXUS DC · MPLS · LDP

Nexus: MPLS with LDP over IS-IS

Five Nexus switches (9504 and 7704 chassis) already run IS-IS Level-2 under tag CORE, with the MPLS feature set enabled. Turn on LDP: every router needs the feature, a stable router ID and mpls ip on its core interfaces. PE1 then reaches PE2’s loopback on a label-switched path.

Nexus DC track · Cisco Nexus (NX-OS-style) · 5 objectives

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Objectives

The simulator ticks each one as soon as the network meets it.

On every switch enable feature mpls ldp (the feature set is already on: show feature-set).
Under mpls ldp configuration, set router-id Loopback0 force on every switch.
Enable mpls ip on every core interface.
LDP sessions are up and PE1 has a label for 5.5.5.5 (show mpls ldp neighbor, show mpls switching).
Ping 5.5.5.5 from PE1: PE1’s LSP uses LDP.

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Before you start

NX-OS keeps MPLS behind a feature set, a step before ordinary features: install feature-set mpls once, feature-set mpls to enable it, and only then feature mpls ldp. mpls ip needs a routed port, so no switchport comes first. The LDP router ID must be reachable through IS-IS, which is why it is a loopback.

Concept

MPLS on NX-OS: a feature set, then features

NX-OS keeps MPLS behind a feature set, one step above ordinary features. The set is installed once and then enabled, and only then do feature mpls ldp, feature mpls traffic-engineering and feature mpls segment-routing exist. Each one in turn makes its own commands appear. The protocols themselves work as on any Cisco router: IS-IS carries the routes, TE data and SIDs, and labels are swapped hop by hop.