I'm doing some tests in my lab preparing for CCIE R&S and I'm diving into how MPLS works and I ran into a issue with getting traceroute to display the label path in it's output. I have not found out why this is not working.

I can ping fine between the CE's.

this is the setup.

CE1 - PE1 - P1 - P2 - PE2 - CE2

P1/P2 only have OSPF enabled with OSPF mpls autoconfig for area 0

CE-PE protocol is BGP

here is the PE2 BGP config:

router bgp 100
 bgp router-id
 bgp log-neighbor-changes
 no bgp default ipv4-unicast
 neighbor remote-as 100
 neighbor update-source Loopback0
 address-family ipv4
  redistribute ospf 1
  neighbor activate
  neighbor send-community
 address-family vpnv4
  neighbor activate
  neighbor send-community extended
 address-family ipv4 vrf CPE2
  redistribute connected
  redistribute ospf 1010
  neighbor remote-as 20
  neighbor activate
  neighbor next-hop-self


ip vrf CPE2
 rd 20:20
 route-target export 200:200
 route-target export 700:700
 route-target import 100:100
 route-target import 700:700

and here are show commands

PE2#show ip bgp vpnv4 vrf CPE2 
BGP table version is 31, local router ID is
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, 
              r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter, 
              x best-external, a additional-path, c RIB-compressed, 
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

     Network          Next Hop            Metric LocPrf Weight Path
Route Distinguisher: 20:20 (default for vrf CPE2)
 *>i                 0    100      0 ?
 *>i                 0    100      0 10 ?
 *>            0             0 20 ?
 *>                  0         32768 ?
 *                      0             0 20 ?
 *>i                 0    100      0 10 ?
 *>            0             0 20 ?

and here is the mpls forwarding table

PE2# show mpls forwarding-table 
Local      Outgoing   Prefix           Bytes Label   Outgoing   Next Hop    
Label      Label      or Tunnel Id     Switched      interface              
1200       Pop Label      0             Et0/0   
1201       Pop Label    0             Et0/0   
1202       Pop Label     0             Et0/0   
1203       Pop Label     0             Et0/0   
1204       Pop Label     0             Et0/0   
1205       Pop Label     0             Et0/0   
1206       202      0             Et0/0   
1207       203      0             Et0/0   
1208       204     0             Et0/0   
1209       205     0             Et0/0   
1210       206     0             Et0/0   
1211       207     0             Et0/0   
1212       208     0             Et0/0   
1213       No Label[V]   \
                                       0             Et1/0
1214       No Label[V]   \
                                       3420          aggregate/CPE2 
1215       No Label[V]   \
                                       696           Et1/0

PE2# show ip bgp vpnv4 vrf CPE2
BGP routing table entry for 20:20:, version 12
Paths: (1 available, best #1, table CPE2)
  Advertised to update-groups:
  Refresh Epoch 2
  20 from (
      Origin incomplete, metric 0, localpref 100, valid, external, best
      Extended Community: RT:200:200 RT:700:700
      mpls labels in/out 1215/nolabel
      rx pathid: 0, tx pathid: 0x0

CPE2#traceroute source lo0
Type escape sequence to abort.
Tracing the route to
VRF info: (vrf in name/id, vrf out name/id)
  1 1 msec 0 msec 0 msec
  2  *  *  * 
  3  *  *  * 
  4  *  *  * 
  5 [AS 100] 1 msec *  0 msec

the Loopbacks of CE1 / CE2 are and So you see that I have the local lable for - that is going from PE2->CE2 non mpls - but what I don't see are labels for the that is going to go over the P routers. the BGP points to and that has a label.

so is this normal - or do I have to make some changes to get the router to create labels for every route - perhaps I'm missing some point here.

  • benni
  • Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you could provide and accept your own answer.
    – Ron Maupin
    Aug 11, 2017 at 15:12

2 Answers 2


but what I don't see are labels for the that is going to go over the P routers. the BGP points to and that has a label - If you have configured PE1 as with next-hop-self then that is how the routes should look.

I suggesst you read more about BGP behaviour for MPBGP sessions and sending labeled updates for IPV4 unicast and VPNV4 etc.


I'm certainly nowhere near the IE level yet, but when I've run into this issue at work, it has usually been that "mpls oam" was not enabled. Your label distribution is working as intended, that's the only reason I could imagine you're not seeing the labels


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