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> ...it is true that when you have a peering point with unbalanced traffic flows, the side sending more traffic is supposed to pay the side receiving more traff

> ...it is true that when you have a peering point with unbalanced traffic flows, the side sending more traffic is supposed to pay the side receiving more traffic. Up until very recently the only time you paid for peering was when you were actually buying transit. Level 3 is definitely on the right side of this argument, not only logically - but also from the perspective of precedence. Anybody interested in learning how the internet actually works should read "The Internet Peering Playbook".

kentonv 12y ago
Hmm, I guess I don't understand why sending packets to an end user over an ISP is not "transit", but I'll go ahead and admit I know very little about this subject and am probably wrong.
- benaiah 12y ago
  It seems that the peering arrangements typically pay for transfer through one network to another, not to get data to the end consumer. I don't know enough about the issue to say whether that's true or not, but that seems to be the argument they're making.
- nitrogen 12y ago
  If it were considered "transit" in the same sense as delivering packets from one network to another across large distances, then consumer Internet access should be free because it's always biased in favor of receiving rather than transmitting bytes. Verizon should even be paying its customers to accept the extra bits they get.
  - kentonv 12y ago
    That doesn't seem entirely obvious, since last-mile infrastructure is a completely different beast from backbones. But yeah, I clearly don't know what I'm talking about at this point. Sorry.
    - nitrogen 12y ago
      I think you understand more than you admit ;-). The last-mile infrastructure is indeed a completely different beast, and Verizon is last-mile infrastructure. So backbone-to-backbone might be symmetric, but backbone-to-last-mile should never have been expected to be symmetric.
- nishonia 12y ago
  ISPs pay for transit, tier 1 networks do not (by definition). Level 3 is definitely a tier 1 network, but Verizon is acting as both a tier 1 and an ISP. It isn't a very complex problem, tier 1 networks don't pay transit.
  - kentonv 12y ago
    I guess that makes a certain arbitrary kind of sense... :)
- toast0 12y ago
  Peering is when you send packets from your network (or your customers' networks) to my network (or my customers' networks). Transit is when you send packets from your network (or your customers' networks) to my network, and I agree to deliver it, regardless of if it's within my network, my customer's networks or beyond my network (via peering or my own transit connections). Peering is historically settlement free at public exchanges and in private connections with balanced traffic. When a private peering is not balanced, historically the peering would be disconnected, but in the mid 2000's, paid peering started showing up more frequently as an option. Paid peering is often less expensive than transit, but it depends on the networks involved and the volume.
- TheCoelacanth 12y ago
  Transit - I send you data and you deliver it to another ISP or backbone provider. Not transit - I send you data and you deliver it to someone in your own network.
  - kentonv 12y ago
    Yeah, the thing is, I don't consider myself to be part of my ISP's network. I consider my ISP to be "transit"ing packets from the internet to my network. :) But I guess that's not the accepted definition.
toast0 12y ago
I was pretty sure the precedent was that high volume peering was for 'balanced flows'. At a public peering point with a shared LAN, balanced flows aren't usually as required, but capacity would usually be less as well. If Level3 (or Netflix) would read the Peering Playbook, they would see that they need to attract some upload traffic from Verizon to balance their flows, and get Verizon to upgrade the links (then, once the links are in place, they can drop the upload traffic). If I were Level3, I would find a backup service or image/video hosting site and convince them to let me advertise their IPs to Verizon/Comcast to balance the flows. I looked for old level3 peering policies, and actually in 2004 they didn't mention balanced flows which was surprising, because most "Tier 1" networks have required balanced flows for peering for a long time. If you don't like Level 3 paying Verizon/Comcast, consider the situation where Verizon has no backbone, and pays for 100% transit from a hypothetical Tier 1 provider. If Level3 doesn't have balanced flows (within usually a 2:1 or 3:1 ratio), most Tier 1's would depeer them as well (or refuse to upgrade circuits).
- nishonia 12y ago
  Flow ratio balance will fall apart for whoever has the shortest route to Netflix, so it is certainly a very interesting problem. Verizon has demonstrated that it isn't interested in fixing the problem though (by refusing Netflix cache devices). So even if Level 3 were to somehow balance the traffic, you can be sure that Verizon would still screw with Netflix traffic - they're simply using the balance argument as an excuse.

kentonv 12y ago

Hmm, I guess I don't understand why sending packets to an end user over an ISP is not "transit", but I'll go ahead and admit I know very little about this subject and am probably wrong.

benaiah 12y ago
It seems that the peering arrangements typically pay for transfer through one network to another, not to get data to the end consumer. I don't know enough about the issue to say whether that's true or not, but that seems to be the argument they're making.
nitrogen 12y ago
If it were considered "transit" in the same sense as delivering packets from one network to another across large distances, then consumer Internet access should be free because it's always biased in favor of receiving rather than transmitting bytes. Verizon should even be paying its customers to accept the extra bits they get.
- kentonv 12y ago
  That doesn't seem entirely obvious, since last-mile infrastructure is a completely different beast from backbones. But yeah, I clearly don't know what I'm talking about at this point. Sorry.
  - nitrogen 12y ago
    I think you understand more than you admit ;-). The last-mile infrastructure is indeed a completely different beast, and Verizon is last-mile infrastructure. So backbone-to-backbone might be symmetric, but backbone-to-last-mile should never have been expected to be symmetric.
nishonia 12y ago
ISPs pay for transit, tier 1 networks do not (by definition). Level 3 is definitely a tier 1 network, but Verizon is acting as both a tier 1 and an ISP. It isn't a very complex problem, tier 1 networks don't pay transit.
- kentonv 12y ago
  I guess that makes a certain arbitrary kind of sense... :)
toast0 12y ago
Peering is when you send packets from your network (or your customers' networks) to my network (or my customers' networks). Transit is when you send packets from your network (or your customers' networks) to my network, and I agree to deliver it, regardless of if it's within my network, my customer's networks or beyond my network (via peering or my own transit connections). Peering is historically settlement free at public exchanges and in private connections with balanced traffic. When a private peering is not balanced, historically the peering would be disconnected, but in the mid 2000's, paid peering started showing up more frequently as an option. Paid peering is often less expensive than transit, but it depends on the networks involved and the volume.
TheCoelacanth 12y ago
Transit - I send you data and you deliver it to another ISP or backbone provider. Not transit - I send you data and you deliver it to someone in your own network.
- kentonv 12y ago
  Yeah, the thing is, I don't consider myself to be part of my ISP's network. I consider my ISP to be "transit"ing packets from the internet to my network. :) But I guess that's not the accepted definition.

toast0 12y ago

I was pretty sure the precedent was that high volume peering was for 'balanced flows'. At a public peering point with a shared LAN, balanced flows aren't usually as required, but capacity would usually be less as well. If Level3 (or Netflix) would read the Peering Playbook, they would see that they need to attract some upload traffic from Verizon to balance their flows, and get Verizon to upgrade the links (then, once the links are in place, they can drop the upload traffic). If I were Level3, I would find a backup service or image/video hosting site and convince them to let me advertise their IPs to Verizon/Comcast to balance the flows. I looked for old level3 peering policies, and actually in 2004 they didn't mention balanced flows which was surprising, because most "Tier 1" networks have required balanced flows for peering for a long time. If you don't like Level 3 paying Verizon/Comcast, consider the situation where Verizon has no backbone, and pays for 100% transit from a hypothetical Tier 1 provider. If Level3 doesn't have balanced flows (within usually a 2:1 or 3:1 ratio), most Tier 1's would depeer them as well (or refuse to upgrade circuits).

nishonia 12y ago
Flow ratio balance will fall apart for whoever has the shortest route to Netflix, so it is certainly a very interesting problem. Verizon has demonstrated that it isn't interested in fixing the problem though (by refusing Netflix cache devices). So even if Level 3 were to somehow balance the traffic, you can be sure that Verizon would still screw with Netflix traffic - they're simply using the balance argument as an excuse.