Networks ignoring prepends?

Mon Jan 22 23:34:17 UTC 2024

> At which point Centurylink chooses 40676 7489 11875 11875 11875 11875
> 11875 11875 11875.
> 
>> This certainly seems like a reasonable path selection, in the context that 47787 is likely a 3356 customer.
> 
> That's -why- 3356 chooses the paths. 40676 and 47787 are customers,
> 1299 is a peer. You're telling me with a straight face that you think
> that's *reasonable* routing?

The reasons why have been pointed out by others:

This is perfectly reasonable routing _if you're 3356_

In this profit-driven world, expecting 3356 to do something that's unprofitable for them just because it happens to be convenient for you is, well, unreasonable.

Deaggregation offers one loophole out of this Layer 8 problem though, making TCAM slots just the price we pay for "my network, my rules". Convincing 53356 and 47787 to add 3356:70 to your route is another. Have you asked them? I know I would look into it if a customer comes to me with a similar request.

Alex