[c-nsp] Best Practices to make one BGP link prefer for egrees and ingress traffic of one subnet

[Arie Vayner]

Muhammad,

As you mention specific destinations that you seem to own/manage on both
ends, wouldn't it make more sense to run some overlay here, with tunnels
taking all available paths, and some simple SD-WAN-like routing policies
selecting the correct overlay for the relevant traffic?

Tnx
Arie

On Mon, Feb 23, 2026, 8:03 AM Muhammad Atif Jauhar <atif.jauhar at gmail.com>
wrote:

> Hi,
> Thank you both for your feedback.
>
> Basically, one subnet is for backup environment and other link is for
> normal user traffic toward Data center.
>
> If we use one link most of the bandwidth captured by backup to avoid any
> bandwidth issue and slowness faced by users, we acquired one link for only
> backup and replication.
>
> Now want to segregate traffic on both link to avoid any bandwidth issue.
>
> Regards,
>
> Muhammad Atif Jauhar
> (+966-5600-04985)
>
> On Mon, Feb 23, 2026, 17:36 Arie Vayner <ariev at vayner.net> wrote:
>
>> Muhammad,
>>
>> To add to Gert's comment about symmetry... Can you please try and explain
>> why you have that requirement?
>>
>> I think this may be a case of reassessing the requirements before going
>> into solution mode.
>>
>> Tnx,
>> Arie
>>
>> On Mon, Feb 23, 2026, 5:36 AM Gert Doering via cisco-nsp <
>> cisco-nsp at puck.nether.net> wrote:
>>
>>> Hi,
>>>
>>> On Mon, Feb 23, 2026 at 02:50:55PM +0300, Muhammad Atif Jauhar via
>>> cisco-nsp wrote:
>>> > However, for outbound traffic, we are presently relying on Policy-Based
>>> > Routing (PBR) to steer traffic via the preferred uplink. While this
>>> > approach is functional, we would prefer to achieve the desired path
>>> > selection using BGP-native mechanisms, if possible, to ensure better
>>> > scalability and operational simplicity.
>>>
>>> There is none.  BGP does not care about packet source addresses.
>>>
>>> (That said, you could trick around with VRFs, but it's questionable
>>> if that will be more satisfactory in the end)
>>>
>>> Symmetric traffic is an illusion, and trying to achieve that in
>>> "the Internet" is time not spent well.
>>>
>>> gert
>>> --
>>> "If was one thing all people took for granted, was conviction that if
>>> you
>>>  feed honest figures into a computer, honest figures come out. Never
>>> doubted
>>>  it myself till I met a computer with a sense of humor."
>>>                              Robert A. Heinlein, The Moon is a Harsh
>>> Mistress
>>>
>>> Gert Doering - Munich, Germany
>>> gert at greenie.muc.de
>>> _______________________________________________
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>>>
>>