I would like to dedicate this post to MPLS L3 VPNs troubleshooting and more particularly using the Traceroute command. It can be sometimes difficult to find out where is the issue when testing connectivity between sites attaches to a MPLS VPN backbone. I will explain the behavior of Traceroute in MPLS VPN environment which is quite different than in “classical” IP environment. Finally I will talk about the MPLS LSP Ping feature and how to use it to detect break in MPLS LSP.
I am using almost the same topology as the one used in this post: Basic MPLS. I have just added a P router.
Cisco 2691/12.4(15)T11 Adv IP services
The following is already configured:
- MP-iBGP between R2 and R5
- EBGP between R2 and R1, R5 and R6
- OSPF area 0 between R2,R3,R4,R5
- LDP between R2,R3,R4,R5
- R3 and R4 are P routers and R2 and R5 are PE routers
- R1 is representing the CE device at Site A announcing its loopback address 22.214.171.124/32
- R2 is representing the CE device at Site B announcing its loopback address 126.96.36.199/32
In this troubleshooting scenario we want to focus on the loopbacks reachability between Site A and Site B.
I must admit that I had the worst night of my entire life before the lab day! I couldn´t sleep and I was thinking about the lab all the time. I think that at the end I slept 1 hour maybe and I woke hope at six O´clock. I went to the sauna to relax during 1 hour but I couldn´t stop thinking about the lab. I think this time I put too much pressure on myself like if I was not going to pass it will be the end of the world! I had some breakfast and than at 7.45 I walked to the lab location (Brussels). By the way, I am staying at the NH hotel which is a nice hotel but don´t expect to get a fast Internet connection. The internet is free but it is really slow and they are so clever to tell you that if you want a better Internet you have to purchase a premium account for 18 €!!! Basically they just rate limit at the maximum the free Internet. All about business;-)
So I walked to the Cisco lab location in Brussels which is at 5 min walking distance from the NH hotel, so it is nice. It was raining that day and the proctor arrived a bit late to pick us up. It was a nice guy with a British accent although he is from Belgium. He told me that he was a CCIE and that he was previously working at Cisco TAC here in Brussels. He explained us the different procedures regarding the lab and for lunch. And then we started with the TS section -> 2 hours. My heard started to beat quite a lot when I saw the topology but then after solving the first tickets I was getting confident. Actually I tried to do all the 2 points tickets first and left the 3 points for the end. I was going quite fast and everything was going really well until I had only 2 tickets and 40 min left. So I thought, ok cool if I solve one of them I can probably pass the TS section! Unfortunately even with plenty of time left I wasn´t able to solve any of them and it is hard feeling when you are so close. I was trying to troubleshoot but during the last 10 min I think I was not troubleshooting anymore as my concentration was gone and the pressure was getting higher and higher and the count down timer on the screen was decreasing so fast. Then you have to accept that you lost and it is really hard because you still have to go through the configuration section and you may think, what is the point anyway? Well I decided to fight to the end even if I knew that I had maybe failed by one ticket! When we went for lunch I was so disappointed, I was feeling horrible! I was so close but close it not enough.
I have spent so much time studying and training, used a lot´s of my holidays and I haven´t seen my family in a year now, that is just crazy!
I am completely exhausted and I need some rest. I will definitely have to learn how to manage the pressure during the TS and train a lot for this section.
I have got the results this morning and I pass the configuration section but as expected, fail the TS section by 2 tickets.
Thanks for reading,