10-29-2020 03:17 AM
This is basic MPLS-VPN LaB i am practicing on GNS3. topology Diagram is attached.
I am unable to ping from PE(R-2) to PE(R-4). routes are showing in neighbor table of BGP but not in routing table.
Please help. I am attaching config files of PE(R2) , PE (R4) and P (R3) routers.
#bgp #Eigrp #MPLS #MPLSVPN #MP-BGP
Solved! Go to Solution.
10-29-2020 06:44 AM - edited 10-29-2020 06:47 AM
Hello @luqman_khalid ,
in order to build a working configuration in the MPLS forwarding plane you need ip ospf network point-to-point to advertise in OSPF a /24 loopback address. Otherwise there is a mismatch between IGP that advertises a /32 and LDP that advertises a /24 and instead of POP action you get show mpls forwarding action UNTAGGEd this breaks the MPLS L3 VPN connectivity.
interface Loopback0
ip address 4.4.4.4 255.255.255.0
ip ospf network point-to-point
!
Do the the same on R2 PE and on P nodes this is a specific issue of OSPF when dealing with loopback interfaces with subnet masks different then 255.255.255.255
Hope to help
Giuseppe
10-29-2020 04:03 AM
Hello,
at first glance, you are missing the 'bgp redistribute-internal' command under the BGP process on R2 and R4...
10-29-2020 04:39 AM
Still not working.
same result. is there any limitation of GNS ?
10-29-2020 05:33 AM
Hello,
post the full configs of all 5 routers so we can lab this...
10-29-2020 06:44 AM - edited 10-29-2020 06:47 AM
Hello @luqman_khalid ,
in order to build a working configuration in the MPLS forwarding plane you need ip ospf network point-to-point to advertise in OSPF a /24 loopback address. Otherwise there is a mismatch between IGP that advertises a /32 and LDP that advertises a /24 and instead of POP action you get show mpls forwarding action UNTAGGEd this breaks the MPLS L3 VPN connectivity.
interface Loopback0
ip address 4.4.4.4 255.255.255.0
ip ospf network point-to-point
!
Do the the same on R2 PE and on P nodes this is a specific issue of OSPF when dealing with loopback interfaces with subnet masks different then 255.255.255.255
Hope to help
Giuseppe
10-31-2020 10:48 AM
Thank you dear , it worked by two different methods.
1: converting Loopback address from /24 to /32.
2: solution proposed by You.
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