6 ms·

> A state actor would (and could trivially) pad the wrong directions This isn't how BGP works. An AS-PATH isn't the path the traffic will follow; it's the pat

by mlyle 9mo ago

> A state actor would (and could trivially) pad the wrong directions This isn't how BGP works. An AS-PATH isn't the path the traffic will follow; it's the path that this overall announcement has allegedly tranversed and is (one of many attributes) used to judge the quality of route. The next hop tells our peer where they should send the data if they like this route. Putting more things in the AS path makes the route less attractive. Leaking a new route isn't going to magically make some other route become more preferred.

darig 9mo ago
[dead]
Fiveplus 9mo ago
You're spot on regarding the mechanics. It's important to reinforce that in BGP, AS-PATH length is a cost metric and not a steering wheel.
geocar 9mo ago
> This isn't how BGP works This is exactly how BGP works. https://bgplabs.net/policy/7-prepend/ https://bgplabs.net/policy/7-prepend/ > Leaking a new route isn't going to magically make some other route become more preferred. Not magic, but technology can look like magic when you don't understand it.
- mlyle 9mo ago
  > > > That's presumptuous: A state actor would (and could trivially) pad the wrong directions to flow traffic down to pops that are not making new announcements > > Leaking a new route isn't going to magically make some other route become more preferred. > Not magic, but technology can look like magic when you don't understand it. Please let me know of the scenario where route A is preferred, undesirable, long-path route B is advertised/leaked, and as a result traffic flows over route C. I've used BGP for over 25 years, so I'm really curious what you're thinking. Or if you're describing something else, you're being really unclear. Or if you're just describing withdrawing a route and replacing it with a really undesirable route -- sure, we do that all the time. But that doesn't match this scenario and isn't going to get flagged as a routing anomaly. > https://bgplabs.net/policy/7-prepend/ https://bgplabs.net/policy/7-prepend/ You know what's really toxic? Not explaining what you mean and just sending some introductory lab documentation about what the other person has already clearly shown they understand. I don't even know what you mean by a lot of these things.. e.g. > > > As soon as I peer with two big sites that don't peer directly with each-other, they both gotta let me forward announcements unfiltered across them. A straightforward reading of "forward" doesn't work for this sentence. I should not take a route from peer A and send it to peer B. Peering isn't transitive. If I try, it should be filtered. Peering means to give your own routes (and your transit customers' routes) to someone else. Not your other peers routes.
  - geocar 9mo ago
    > Please let me know of the scenario where route A is preferred, undesirable, long-path route B is advertised/leaked, and as a result traffic flows over route C. > ... I'm really curious what you're thinking That the actor actually wanted the traffic to flow over route C. > You know what's really toxic? Not explaining what you mean and just sending some introductory lab documentation about what the other person has already clearly shown they understand. I think perhaps you and I have different ideas of what is "clear", for example when you said something that is totally covered in introductory lab documentation, I thought it was clear that you did not understand. > I don't even know what you mean by a lot of these things That is clear! But confusing! How can you clearly understand but not know what I mean? > Peering means to give your own routes (and your transit customers' routes) to someone else. That's exactly what's happening here: Not every transit customer peers with every other transit customer.
    - mlyle 9mo ago
      > > Please let me know of the scenario where route A is preferred, undesirable, long-path route B is advertised/leaked, and as a result traffic flows over route C. Yes, but how does advertising undesirable route B make traffic go over route C? This is why I think you're confused. > That's exactly what's happening here: Not every transit customer peers with every other transit customer. I am not understanding what you're saying at all. You said: > > > > As soon as I peer with two big sites that don't peer directly with each-other, they both gotta let me forward announcements unfiltered across them. This is the thing you are supposed to never do as a peer, and the thing that I have a whole bunch of filtering to prevent my peers from inadvertently doing. Are you misusing the word "peer"? It's hard to talk about BGP and routing policy without using these words correctly. I think I'm going to give up here.
      - geocar 9mo ago
        > This is why I think you're confused. I think you're confused. > I am not understanding what you're saying at all. And that is why; You seem to have a very strong opinion about something that you don't understand "at all" and frankly I cannot understand how that can work. > This is the thing you are supposed to never do as a peer So you say, but that's what I did when back in the early 2000s, and that's what the parties in the news were doing, and if you're not totally lying to me, you know this because it's the default in BGP, that's why you would say you need to: > I have a whole bunch of filtering to prevent my peers from inadvertently doing. because that's how BGP works. Duh. > It's hard to talk about BGP without using these words correctly. and I am flabbergasted you continue to persist at it, when I have even offered you "introductory lab documentation" to help.
deleted 9mo ago
[deleted]
codexon 9mo ago
Actually many networks will prefer routing over a cheap AS path no matter how long it is.
- mlyle 9mo ago
  > > and is (one of many attributes) used to judge the quality of route
  - codexon 9mo ago
    Lower cost usually means lower quality and is an example of how a long path being leaked can result in traffic flowing away from high quality path to the leaked path. Not saying that this is the case with Venezuela, just explaining the reality of BGP where path prepends are often ignored.
    - mlyle 9mo ago
      His claim-- as best as I can read it-- is that B leaking a long-length route changes where traffic is routed, but not to B. It's possible he's saying something else, but I can't figure out, and he hasn't clarified.

by mlyle 9mo ago

darig 9mo ago

[dead]

Fiveplus 9mo ago

You're spot on regarding the mechanics. It's important to reinforce that in BGP, AS-PATH length is a cost metric and not a steering wheel.

geocar 9mo ago

> This isn't how BGP works This is exactly how BGP works. https://bgplabs.net/policy/7-prepend/ https://bgplabs.net/policy/7-prepend/ > Leaking a new route isn't going to magically make some other route become more preferred. Not magic, but technology can look like magic when you don't understand it.

mlyle 9mo ago
> > > That's presumptuous: A state actor would (and could trivially) pad the wrong directions to flow traffic down to pops that are not making new announcements > > Leaking a new route isn't going to magically make some other route become more preferred. > Not magic, but technology can look like magic when you don't understand it. Please let me know of the scenario where route A is preferred, undesirable, long-path route B is advertised/leaked, and as a result traffic flows over route C. I've used BGP for over 25 years, so I'm really curious what you're thinking. Or if you're describing something else, you're being really unclear. Or if you're just describing withdrawing a route and replacing it with a really undesirable route -- sure, we do that all the time. But that doesn't match this scenario and isn't going to get flagged as a routing anomaly. > https://bgplabs.net/policy/7-prepend/ https://bgplabs.net/policy/7-prepend/ You know what's really toxic? Not explaining what you mean and just sending some introductory lab documentation about what the other person has already clearly shown they understand. I don't even know what you mean by a lot of these things.. e.g. > > > As soon as I peer with two big sites that don't peer directly with each-other, they both gotta let me forward announcements unfiltered across them. A straightforward reading of "forward" doesn't work for this sentence. I should not take a route from peer A and send it to peer B. Peering isn't transitive. If I try, it should be filtered. Peering means to give your own routes (and your transit customers' routes) to someone else. Not your other peers routes.
- geocar 9mo ago
  > Please let me know of the scenario where route A is preferred, undesirable, long-path route B is advertised/leaked, and as a result traffic flows over route C. > ... I'm really curious what you're thinking That the actor actually wanted the traffic to flow over route C. > You know what's really toxic? Not explaining what you mean and just sending some introductory lab documentation about what the other person has already clearly shown they understand. I think perhaps you and I have different ideas of what is "clear", for example when you said something that is totally covered in introductory lab documentation, I thought it was clear that you did not understand. > I don't even know what you mean by a lot of these things That is clear! But confusing! How can you clearly understand but not know what I mean? > Peering means to give your own routes (and your transit customers' routes) to someone else. That's exactly what's happening here: Not every transit customer peers with every other transit customer.
  - mlyle 9mo ago
    > > Please let me know of the scenario where route A is preferred, undesirable, long-path route B is advertised/leaked, and as a result traffic flows over route C. Yes, but how does advertising undesirable route B make traffic go over route C? This is why I think you're confused. > That's exactly what's happening here: Not every transit customer peers with every other transit customer. I am not understanding what you're saying at all. You said: > > > > As soon as I peer with two big sites that don't peer directly with each-other, they both gotta let me forward announcements unfiltered across them. This is the thing you are supposed to never do as a peer, and the thing that I have a whole bunch of filtering to prevent my peers from inadvertently doing. Are you misusing the word "peer"? It's hard to talk about BGP and routing policy without using these words correctly. I think I'm going to give up here.
    - geocar 9mo ago
      > This is why I think you're confused. I think you're confused. > I am not understanding what you're saying at all. And that is why; You seem to have a very strong opinion about something that you don't understand "at all" and frankly I cannot understand how that can work. > This is the thing you are supposed to never do as a peer So you say, but that's what I did when back in the early 2000s, and that's what the parties in the news were doing, and if you're not totally lying to me, you know this because it's the default in BGP, that's why you would say you need to: > I have a whole bunch of filtering to prevent my peers from inadvertently doing. because that's how BGP works. Duh. > It's hard to talk about BGP without using these words correctly. and I am flabbergasted you continue to persist at it, when I have even offered you "introductory lab documentation" to help.

deleted 9mo ago

[deleted]

codexon 9mo ago

Actually many networks will prefer routing over a cheap AS path no matter how long it is.

mlyle 9mo ago
> > and is (one of many attributes) used to judge the quality of route
- codexon 9mo ago
  Lower cost usually means lower quality and is an example of how a long path being leaked can result in traffic flowing away from high quality path to the leaked path. Not saying that this is the case with Venezuela, just explaining the reality of BGP where path prepends are often ignored.
  - mlyle 9mo ago
    His claim-- as best as I can read it-- is that B leaking a long-length route changes where traffic is routed, but not to B. It's possible he's saying something else, but I can't figure out, and he hasn't clarified.