And even with those things being in-band, we now have authentication for BGP and the IGPs to try and constrain the ability to send control signals. SS5/CCITT5 w

And even with those things being in-band, we now have authentication for BGP and the IGPs to try and constrain the ability to send control signals. SS5/CCITT5 would probably have played out a lot differently had they hand the ability to do that sort of thing like we do now.