Routing
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Routing

Hierarchical Route Reflectors

[ Edited ]
‎06-14-2020 04:59 PM

Hey guys,

I have a question regarding Hierarchical RR design. my topology is as attached. when I peer RR-1 and RR-2 together everything works, but when I try to deploy using the hierarchical design I see unexpected behavior.  Each PE has the following 2 instancens:

Instance-A

Instance-B 

 

When RR-1 and RR2 are directly peered with eachother both instances are populated with routes just fine. below is how I configure them. so far so good. 

RR-1 Cluster id: 1.1.1.1, neighbors/clients in the same group as cluster id config: PE1-Market1/ RR2

RR-2 Cluster id: 2.2.2.2, neighbors/clients in the same group as cluster id config: PE1-Market2/ RR1

 

However the hierarchical Route Reflectors are causing some odd behavior. here is the setup:

 

RR-Main Cluster id: 9.9.9.9,neighbors/clients in the same group: RR-1, RR-2

 

RR-1 peers as a client to RR-Main with no cluster-id in this bgp group

RR-1 Cluster id: 1.1.1.1, neighbors/clients in the same group: PE1-Market1

 

RR-2 peers as a client to RR-Main with no cluster-id in this bgp group

RR-2 Cluster id: 2.2.2.2, neighbors/clients in the same group: PE1-Market2

 

Here is where things become interesting....

PE1-Market1/PE1-Market2 can see eachothers Instance-A route, so far so good. 

PE1-Market1 sees PE1-Market-2 routes for Instance-B

PE1-Market2 DOES NOT see PE1-Market-1 routes for Instance-B.

 

Instance A and B both have other PEs in each market, (both instance work correctly within each market), and this issue seems to only be related to inter-market reflection as soon RR-Main is used. the weird thing is its only one-way. the only thing thtas different between Instance-A/B is that B is using an autonomous-system that is different from global table, and I am using independent-domain on Instance-B. I dont suspect this is an issue because PE1-Market1 sees PE1-Market2 routes but not the other way around. 

 

I appologize in advance, I wont be able to share config but tried explaining the problem as detailed as possible. any suggestion is highly appreciated. thanks! 

2 REPLIES 2
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Routing

Re: Hierarchical Route Reflectors

[ Edited ]
‎06-14-2020 08:54 PM

Hello,

 

Check if You have the same RD for instance B on both PEs. These types of issues typically occur when using the same RD and the rest of BGP attributes are equal so the BGP path selection decision falls down to router-id.

 

HTH

Thx

Alex

 

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Routing

Re: Hierarchical Route Reflectors

‎06-15-2020 10:28 AM

Hi Alex, that doesnt seem to be the problem. I have Unique RD on those instances. 

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