Category Archives: L3 VPN

The Corner Case of the Missing MPLS Labels in Traceroute Output on an ISR G2 CE Router!

Life comes at you fast…so do the results from the traceroute command when trying to see exactly which hops across a provider MPLS L3 VPN network you are transiting! But what happens when your Customer Edge (CE) router is an ISR G2-series and your traceroute output shows NO MPLS labels in its output??? I know, I know, you are thinking that the Provider Edge (PE) router must have the ‘no mpls ip propagate-ttl’ command configured…that’s what I thought it was too! Not so fast my friends!

In this video tutorial I go over the ‘corner case’ recently encountered by a colleague where he saw the MPLS provider core router hops, but with no MPLS labels to speak of and why, irrespective of whether you are actually running MPLS on the CE router, you won’t see any MPLS labels if you don’t have the ‘DATAK9’ license installed! Crazy, I know…