Skip to main content

MPLS Troubleshooting Tips

Anyone of you having difficulty in troubleshooting MPLS as a beginner?
I did some research and take notes for myself and now it is for you to do reference as well.

MPLS troubleshooting can be divided into two main steps:

1) Verify routing information flow
2) Verify proper data flow

- Routing information flow troubleshooting requires verification of end-to-end routing information propagation between CE routers.
- Verification of the routing information flow should be done systematically, starting at the routing ingress CE and moving to the egress CE.
- Verification of the data flow should be done systematically, starting at the data flow ingress CE and moving to the egress CE.

There are three things to perform basic MPLS troubleshooting.
They are,
1) Preliminary steps in MPLS VPN Troubleshooting:
- Is CEF enabled?
- Are labels for IGP routes generated and propagated?
- Are large labeled packets propagated across the MPLS backbone (maximum transmission unit issues)?

2) Verify the routing information flow:
- Are CE routes received by a PE?
- Are routes redistributed into MP-BGP with proper extended communities?
- Are VPNv4 routes propagated to other PE routers?
- Is the BGP route selection process working correctly?
- Are VPNv4 routes inserted into VRFs on other PE routers?
- Are VPNv4 routes redistributed from BGP into the PE-CE routing protocol?
- Are IPv4 routes propagated to other CE routers?

3) Verify proper data flow:
- Is CEF enabled on the ingress PE router interface?
- Is the CEF entry correct on the ingress PE router?
- Is there an end-to-end label switched path tunnel (LSP tunnel) between PE routers?
- Is the LFIB entry on the egress PE router correct?

Do you have/know something that I missed out in my above list? Please assist me by letting know. Thanks.

Have a good day.
(Be knowledgeable, pass it on then)


  1. SkyPakistan providing latest update about Pakistan dramaz Pakistan Showbiz technology, bollywood, hollywood, lollywood, sport's stars, pakistan showbiz & gossips PakistanDramaz.

  2. movers and packers in dubai marina Noor Ahmad Transport is a Mover and Packer service provider in Dubai Marina. Pickup Truck Rental Dubai 1/3 Ton - 7/10 Ton Truck with Tail Lift. Home/Office Shifting, Man with van service in Dubai. Call: 050 651 2943


Post a Comment

Popular posts from this blog

Fortigate guide for Begineer - 6

I would like to explaine how to troubleshoot the Fortigate Unit configured by Transparent Mode in step by step this time. Let's assume, you have one Fortigate Unit that configured as Transparent Mode. But devices from Internal/Private Network unable to access Internet/Public Network through your Fortigate Unit. OK. Let's troubleshoot with following steps, 1) Check the physical network connections between the network and the FortiGate unit, and between the FortiGate unit and the Internet. 2) Check the router and ISP-supplied equipment to make sure it is operating correctly. 3) Verify that you can connect to the internal interface by connecting to the management IP address of the FortiGate unit from the Internal network. From the internal network, attempt to ping the management IP address. If you cannot connect to the internal interface, verify the IP configuration of the PC and make sure the cables are connected and all switches and other devices on the network are powered on a

Solving the "A general system error occured:Invalid fault" error in vSphere 4

Below error was come out when you try to migrate VM to other host for some reason. Below error was come out when you try to edit VM setting. Below error was come out when you power on the VM. How to solve those error? Here is how I resolve the error! Login to the Host that errored VM exist by using Terminal or Direct Console. Enter below command and press enter. restart Wait until all VMware Services are restarted. After that try to Power On/Edit Settings or Migrate the errored VM and you will see all you can do without any error pop-up. This kind of errors can occur if you shutdown/restart VM unproperly or shutdown/restart the Host unproperly that VM exist. You can check log file deeply if you willing to know precisely on this. May you all be happy. (Be knowledgeable, pass it on then)

Link Aggregating with Synology NAS and Cisco Switch

I’d like to share how to setup Link Aggregating between Synology NAS and Cisco Switch. I’ve got one Synology NAS with 4 Network Ports and I’m going to use 2 of them. Both Network Port to be as one Logical Link, Fault Tolerance and Load Balancing. To do that, I need to configure Link Aggregating on Synology NAS and EtherChannel with LACP on Cisco Switch. Below is brief steps to do to meet with my requirements. - Get connected Synology NAS and Cisco Switch as shown in picture. - Bonding two Network Ports of Synology NAS and assign IP Address - Configure EtherChannel with LACP in Cisco Switch and add two physical ports as Member. OK. Let’s begin from Synology NAS. - Login to the Synology and go to Control Panel>Network>Create>Create Bond - Select IEEE 802.3ad to get Fault Tolerance and Load Balancing Featureyou’re your switch not support 802.3ad you can only select Fault Tolerance only feature). After that click “Next”. - Choose the network port f