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Highlighted
Beginner

Fusion and Border design/tuning for handoff

Hello,

I am configuring the handoff part of the SD-Access for my customer.
To summarize, we have the following VRF/VN :
- GRT/DEFAULT_VN : Underlay
- Corporate_VN

For GRT/DEFAULT_VN and Corporate_VN, the eBGP will finish on fusion routers (catalyst 9500)

1- According to cisco documents, I have initially configured BGP on fusion routers with "maximum-path 2" parameter. But on Border, DNAC do not configure that for the VRF. Do I have to manually add this parameter for each address-family on borders ?

2- On Borders nodes, interconnection subnets (/30) for each VRF are annonced on BGP with network command. For me, it is useless. According to cisco documents, initial configuration of the border (GRT) do not announced interconnection subnets (/30) in GRT.

3- For redundancy, is therebest practices about BGP timers ?

Many thanks for your help.

Regards,

Hugo

2 ACCEPTED SOLUTIONS

Accepted Solutions
Highlighted
Beginner

Re: Fusion and Border design/tuning for handoff

I'll answer your questions inline below:

1- According to cisco documents, I have initially configured BGP on fusion routers with "maximum-path 2" parameter. But on Border, DNAC do not configure that for the VRF. Do I have to manually add this parameter for each address-family on borders ?

ChuckMcF: We manually configured ours (maximum-paths eibgp 2 since our EBNs are connected via iBGP and FRs are eBGP). For clarity, we have dual FR and dual EBNs in our SDA network.

 

2- On Borders nodes, interconnection subnets (/30) for each VRF are annonced on BGP with network command. For me, it is useless. According to cisco documents, initial configuration of the border (GRT) do not announced interconnection subnets (/30) in GRT.

ChuckMcF:we do not have interconnects advertised via network statements. I agree, no point. The only network statements are for those networks in the specific VRFs.

 

3- For redundancy, is therebest practices about BGP timers ?

ChuckMcF: my suggestion would be to leave timers alone and use BFD.

VLAN xxxx

bfd interval 100 min_rx 100 multiplier 3

router bgp xxxxx

neighbor a.b.c.d fall-over bfd

 

HTH,

Chuck McFadden

View solution in original post

Highlighted
Beginner

Re: Fusion and Border design/tuning for handoff

Do I have to manually add this parameter for each address-family on borders ?

 

It depends, you only need this command if you have more than one link. If your Border and Fusion have single connections, you don't need to worry about it.

 

2- On Borders nodes, interconnection subnets (/30) for each VRF are annonced on BGP with network command. For me, it is useless. According to cisco documents, initial configuration of the border (GRT) do not announced interconnection subnets (/30) in GRT.

 

EBGP next hop is changed, iBGP isn't. So that's one thing to consider. If you're using EBGP, the /30's are really only handy for testing. I.E, if you want to ping from one /30 to another /30, you'd need those routes end to end. Going back in to your Shared Ssrvices though, you really need the /32's from each router within your Fabric Domain.

 

3- For redundancy, is therebest practices about BGP timers ?

 

If you own the access network, you can set these really low, plus add BFD.

View solution in original post

4 REPLIES 4
Highlighted
Beginner

Re: Fusion and Border design/tuning for handoff

I'll answer your questions inline below:

1- According to cisco documents, I have initially configured BGP on fusion routers with "maximum-path 2" parameter. But on Border, DNAC do not configure that for the VRF. Do I have to manually add this parameter for each address-family on borders ?

ChuckMcF: We manually configured ours (maximum-paths eibgp 2 since our EBNs are connected via iBGP and FRs are eBGP). For clarity, we have dual FR and dual EBNs in our SDA network.

 

2- On Borders nodes, interconnection subnets (/30) for each VRF are annonced on BGP with network command. For me, it is useless. According to cisco documents, initial configuration of the border (GRT) do not announced interconnection subnets (/30) in GRT.

ChuckMcF:we do not have interconnects advertised via network statements. I agree, no point. The only network statements are for those networks in the specific VRFs.

 

3- For redundancy, is therebest practices about BGP timers ?

ChuckMcF: my suggestion would be to leave timers alone and use BFD.

VLAN xxxx

bfd interval 100 min_rx 100 multiplier 3

router bgp xxxxx

neighbor a.b.c.d fall-over bfd

 

HTH,

Chuck McFadden

View solution in original post

Highlighted
Beginner

Re: Fusion and Border design/tuning for handoff

Many thanks for these clarifications.

 

Highlighted
Beginner

Re: Fusion and Border design/tuning for handoff

Do I have to manually add this parameter for each address-family on borders ?

 

It depends, you only need this command if you have more than one link. If your Border and Fusion have single connections, you don't need to worry about it.

 

2- On Borders nodes, interconnection subnets (/30) for each VRF are annonced on BGP with network command. For me, it is useless. According to cisco documents, initial configuration of the border (GRT) do not announced interconnection subnets (/30) in GRT.

 

EBGP next hop is changed, iBGP isn't. So that's one thing to consider. If you're using EBGP, the /30's are really only handy for testing. I.E, if you want to ping from one /30 to another /30, you'd need those routes end to end. Going back in to your Shared Ssrvices though, you really need the /32's from each router within your Fabric Domain.

 

3- For redundancy, is therebest practices about BGP timers ?

 

If you own the access network, you can set these really low, plus add BFD.

View solution in original post

Highlighted
Beginner

Re: Fusion and Border design/tuning for handoff

Thank for your help
Hugo
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