topic Re: issue about sdwan bgp routing in General Topics

issue about sdwan bgp routing

miaocongcong — Tue, 27 Aug 2024 15:51:18 GMT

HI , Bro

I setup a hub-spoke sdwan on my pnet lab

Hub can learn site1 and site2 internal routing , but it can not pass these routing entry between site1 and site2.
which cause hub and spoke(site1 and site2) can access each other , but the spoke (site1 and site2) can not access each other.

Re: issue about sdwan bgp routing

TomYoung — Wed, 04 Sep 2024 14:58:06 GMT

Hi @miaocongcong ,

What is the next hop for the prefixes in the Local RIB on the spokes? Is that IP address in the routing table? If the BGP next hop is not reachable, the prefix will not be added to the routing table.

https://knowledgebase.paloaltonetworks.com/KCSArticleDetail?id=kA10g000000ClL1CAK&refURL=http%3A%2F%2Fknowledgebase.paloaltonetworks.com%2FKCSArticleDetail

Thanks,

Tom

Re: issue about sdwan bgp routing

sridic — Thu, 26 Sep 2024 14:49:06 GMT

@miaocongcong by default hub will not pass branch routes to all other branches. in hub/spoke topology assumption is that for any branch to talk to another branch, it has to travers hub so in this case a summary route for all branch subnets advertised from branch is adequate and can direct traffic between branches.
If you need to pass branch routes to each other via hub you can create BGP import rule on hub to append hub specific community string on all received routes. This community is hashed from hub specific loopback, so it is unique for each site. More details on this are available here: https://docs.paloaltonetworks.com/content/dam/techdocs/en_US/pdf/sd-wan/experts/pan-os-sd-wan-auto-provisioning-primer.pdf