MPLS forwarding table outgoing interface drop?

Deniz AYDIN · ‎09-29-2009

Hi,

what is mean outgoing interface drop in the output of

show mpls forwarding-table

command output

XXXX#show ip route vrf YYY 192.168.1.0

Routing entry for 192.168.1.0/24

Known via "bgp 6000", distance 200, metric 0, type internal

Last update from 192.168.128.77 00:06:59 ago

Routing Descriptor Blocks:

* 192.168.128.77 (Default-IP-Routing-Table), from 192.168.128.39, 00:06:59 ago

Route metric is 0, traffic share count is 1

AS Hops 0

MPLS Required

XXXX#

XXXX#show ip bgp vpnv4 vrf YYY 192.168.1.0

BGP routing table entry for 6000:5300:192.168.1.0/24, version 15713

Paths: (1 available, best #1, table YYY)

Not advertised to any peer

Local, imported path from 6000:4250:192.168.1.0/24

192.168.128.77 (metric 29) from 192.168.128.39 (192.168.128.39)

Origin IGP, localpref 100, weight 32768, valid, internal, best

Extended Community: RT:6000:4250 RT:6000:4800

Originator: 192.168.128.77, Cluster list: 0.0.0.10

mpls labels in/out nolabel/16

XXXX#

XXXX#show mpls forwarding-table vrf YYY 192.168.1.0 detail

Local Outgoing Prefix Bytes Label Outgoing Next Hop

Label Label or VC or Tunnel Id Switched interface

None No Label 192.168.1.0/24[V] \

0 drop

MAC/Encaps=0/0, MRU=0, Label Stack{}

VPN route: YYY

No output feature configured

XXXX#

Giuseppe Larosa · ‎09-29-2009

Hello Deniz,

the vpnv4 route looks like imported in VRF YYY.

I would check

sh mpls forw 192.168.128.77 to see if LSP is correct to BGP next-hop.

>> MPLS required

This is the first step to do in my opinion.

Second note:

sh ip bgp vpnv4 vrf YYY 192.168.1.0 shows out label 16

but sh mpls forw vrf YYY 192.168.1.0 shows an empty label stack it should show the BGP label 16.

Hope to help

Giuseppe

Deniz AYDIN · ‎09-29-2009

Hi Giuseppe ,

It has correct next-hop record ,

XXXX#show mpls forwarding-table 192.168.128.77 detail

Local Outgoing Prefix Bytes Label Outgoing Next Hop

Label Label or VC or Tunnel Id Switched interface

118 No Label 192.168.128.77/32 0 Gi0/3.201 192.168.122.2

MAC/Encaps=18/18, MRU=1504, Label Stack{}

0019E28498DB001380479319810000C90800

No output feature configured

XXXX#

router gets the correct bgp label (i checked it from the other vpn nodes also) it seems it getting the correct tag from the downstream router. But its not installing it.

Giuseppe Larosa · ‎09-30-2009

Hello Deniz,

I see

No Label as outgoing label for 192.168.128.177:

local label 118 but outgoing label no label

it should be a label value or pop tag.

check if you have a filter for label association and if LDP sessions are up with

sh mpls ldp discovery

Hope to help

Giuseppe

ananto yudi hendrawan · ‎01-12-2012

Hello Deniz

I also faced the same problem here

R1#sho ip route vrf ZZZ 10.5.82.242

Routing Table: ZZZ

Routing entry for 10.5.82.242/32

Known via "static", distance 1, metric 0

Redistributing via bgp 65000

Advertised by bgp 65000

Routing Descriptor Blocks:

* 10.5.82.97

Route metric is 0, traffic share count is 1

R1#sho mpls forwarding-table vrf Gn_VRF 10.5.82.242

Local Outgoing Prefix Bytes Label Outgoing Next Hop

Label Label or VC or Tunnel Id Switched interface

None No Label 10.5.82.242/32[V] 0 drop

I still trying to find the explanation about this on the internet, but I could solved this problem with action below

R1#conf t

Enter configuration commands, one per line. End with CNTL/Z.

R1(config)#interface loopback 100

R1(config-if)#ip vrf forwarding ZZZ

R1(config-if)#ip address 10.5.82.242 255.255.255.255

R1(config-if)#no interface loopback 100

R1(config-if)#^Z

R1#sh mpls forwarding-table vrf Gn_VRF 10.5.82.242

Local Outgoing Prefix Bytes Label Outgoing Next Hop

Label Label or VC or Tunnel Id Switched interface

250 No Label 10.5.82.242/32[V] 42318 Gi3/29 10.5.82.97

German Tomkowicz · ‎11-12-2013

HI, I have the same problem now, but with several networks.

Do you found an explanetion for this behaviour ?

Alessio Andreoli · ‎11-17-2013

Hi,

assuming you are using LDP to bind your prefixes you should try :

sh mpls ldp nei

#this is to check that your PE has an effective label distribution process

sh mpls for vrf YYY

#check what is happening inside your VRF in terms of mplsforwarding

sh ip cef vrf YYY A.B.C.D detail

#check the next hop in the CEF table.

Make sure the CEF table is on.

sh ip route vrf YYY

# check the routes inside your VRF

sh bgp vpnv4 uni all

# check the prefixes sourced by VPNv4

sh bgp vpnv4 uni all summ

#check the status of your BGP VPNv4 session

Alessio

Jan Linhart · ‎01-17-2014

Is "ip cef" turned on? this is typical example how router behaves when cef is off.