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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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