iBGP multipath in ADVPN - SDWAN

[rajamanickam]

Hello, I have 2 spokes and a branch.. 

Spoke 1 and Spoke 2 has 2 MPLS underlays. Hub has 2 MPLS and internet underlay (Internet underlay to handle traffic from other spokes). Spoke1 LAN network 10.1.1.0/24, Spoke2 LAN network 10.11.1.0/24..

I did ADVPN configs with all recommended commands at HUB and spoke (Netdevice disabled at Hub and Netdevice enabled at spoke, auto discovery etc).. Since I have two underlays in each spoke and two MPLS at HUB, I will have 4 tunnels (4paths) from each spoke to Hub. so my spoke 1 advertises 10.1.1.0/24 over 4 tunnels to HUB.. Hub is receiving it and could see 4 routes in the command output of get rotuer info routing table bgp. But when I use the command  get router info bgp network, I could see only 2 routes have been selected as best (instead of 4). This two routes are getting advertised as 6 routes (with same next hop) to spoke 2...  The next hop is not showing in the route table so that ADVPN gets established.. but I could see the IPs of the two dialup tunnel IP (which is not getting selected as best route in ) in the routing table as directly connected route. I am not sure, what config I have missed in BGP to see this behaviour. Due to this my ADVPN not working..

[Anthony_E]

Hello rajamanickam,

Thank you for using the Community Forum. I will seek to get you an answer or help. We will reply to this thread with an update as soon as possible.

Thanks,

[Anthony_E]

Hi Raja,

I have made some research in our Knowledge Base:

https://community.fortinet.com/t5/forums/searchpage/tab/message?searchString=ADVPN&from=0&sortby=_sc...

There is a list of articles which could be useful for you.

Could you please have a look and tell me if it helped you?

If not, we will find another way to reply to your answer.

Regards,

[rajamanickam]

Hi, Let me go through this link...

[akristof]

Hello,

If you didn't check this, check this:

https://docs.fortinet.com/document/fortigate/6.2.0/cookbook/773406/bgp-multiple-path-support

With 4 tunnels, this example should be exactly your scenario.

[rajamanickam]

Thanks for the link, after configuring additional path 4. I could see DC electing 4 best paths which are being advertised to other branches. But however still ADVPN is not working. I have raised a TAC case on this. Since I have all required policies, SDWAN rules, routes but still ADVPN between branches are not working.

Regards

Raja

[martini]

Did you every get this issue resolved? 

[Julien87]

Hello Raja,

Have you a reply from TAC case ? I have a similar problem. Only networks HUB are learn from my branches. 

Thanks for your reply.

Julien

[akristof]

Hi,

Create separate community post and we can check it.

[Julien87]

Hi Adrien,

no problem, i post a new community post.

Best Regards,