MPLS Config

Unanswered Question
Apr 10th, 2009

I want to create one scenario using L3 VPN MPLS.Can any one tell me what config is require on R1,R2,R3,R4 in MPLS cloud.

So that i can ping CE2 from CE1.

Pls find the attachment.


I have this problem too.
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Giuseppe Larosa Sat, 04/11/2009 - 08:26

Hello Arjun,

the following steps are required:

a) building the network infrastructure using an IGP: for example OSPF

Allocate /32 loopbacks on all R1-R4.

For example:

Ri : Loop0 ip address 10.250.250.i/32

int loop0

ip address 10.250.250.i

desc loop used as LDP router-id, BGP RID

network infrastructure:

let's suppose we use with subnettting for all backbone links between R1-R4

OSPF config

router ospf 10

router-id 10.250.250.i

network area 0

network 10.250.250.i area 0

verify you can ping from loopback to loopback using extended ping

b) enable MPLS on all routers

ip cef

mpls ip

mpls label protocol ldp

mpls ldp router-id loop0 force

on all backbone interfaces with ip addresses in add

int type x/y

mpls ip

verify again connectivity of loopbacks

verify with

sh mpls forwarding 10.250.250.i

what action is associated to each loopback

c) enable iBGP multiprotocol

let's use AS 65000

router bgp 65000

bgp router-id 10.250.250.i

no bgp default ipv4-unicast

neigh 10.250.250.j remote-as 65000

neigh 10.250.250.j update-source loop0

! do it for all three other routers

address-family vpnv4

neigh 10.250.250.j activate

neigh 10.250.250.j send-community both

! again do this for all three routers


sh ip bgp vpvn4 all summary to check

every router should see 0 prefixes from the other three

d) create the VRF

ip vrf TEST

rd 65000:101

route-target export 65000:1001

router-targer import 65000:1001

associate the link to CE with the VRF

int type x/y

ip vrf forwarding TEST

! caution you need to retype the ip address command as desired

router bgp 65000

address-family ipv4 vrf TEST

red connected

no sync

do this on both R1 and R2

now if you do

sh ip bgp v a s you should 1 prefix advertised by R1 and 1 by R2.


there can be some syntax errors

I wrote on the fly


to be able to ping from LAN to LAN you need to decide how PE and CE should communicate.

the simplest solutions are:

static routes

or an eBGP session to be configured on the PE side under

router bgp 65000

address-family ipv4 vrf TEST

for static routes:

red static

for eBGP session:

neighbor CE-address remote-as 65200

for static routes the keyword vrf TEST has to be added to the command

Hope to help


arjunsawant Sun, 04/12/2009 - 19:26

Hi Giuseppe ..

Thanks a Lot..!

This is very usefull to me.

Once again Thankx...


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