Traffic ratio of an ISP

Good morning.
I’m a Ph.D. candidate from University of Central Florida. I have a query, I hope you can help me with it or at least point me to the right direction.
I’ve seen from PeeringDB that every ISP reveals its traffic ratio as Heavy/ Mostly Inbound or Balanced or Heavy/ Mostly Outbound.
I’m wondering if there is any specific ratio numbers for them. In Norton’s Internet Peering Playbook or some other literary work, they mention the outbound:inbound traffic ratio as 1:1.2 to up to 1:3 for Balanced. But, I couldn’t find the other values.
I’d really appreciate your help if you can please mention what Outbound:Inbound ratios that network admins use frequently to represent their traffic ratios for

  1. Heavy Inbound:
  2. Mostly Inbound:
  3. Mostly Outbound:
  4. Heavy Outbound:

Thank you.

If you’re asking an ISP, consumers will always be inbound. It’s the end user. The outbound would be where the information is coming from, like data centers.

It kinda depends on the application that’s being used. For example, videogaming has a ratio somewhere around 1:2.5 since you’re only transmitting metadata about the players environment across the wire. The actual video is typically rendered at the end user’s side. So it’s not very bandwidth heavy.

Compare that with a videostream (watching a movie or TV series) and you’re pumping the rendered video across the wire, so there’s a very different ratio. Your return path traffic would pretty much consist of control stuff only (like pushing the pause button).

Some networks are dedicated to serving one type of content, whereas others might have a blend of different kinds of content. Same story for an access network geared to business users which want to use emails and such, vs residential end users looking for the evening’s entertainment.

Best regards,

Hi Prasun,

Ratio only masquerades as a technical term. It’s whatever it takes to convince the other guy to set up settlement-free peering and you’ll tweak your routing adjusting reality to match. The information in peeringdb is just a rough guide to help you figure out who to talk to as you try to adjust your traffic profile so that you can go after the big fish as “balanced.”

Bill Herrin

I run an eyeballs/isp network for about ~50,000 subscribers, and I see about 1:10 ratio at peak time. Last night ~4.5 gbps out, ~45 gbps in. But, I do have local caching of 4 big name cdn cache providers, so that might alter the 1:10 ratio I see on my actual inet links (which do not include the local cdn traffic)

…take Netflix for instance… I see on my local nfx cdn links, 1:100 ratio of in:out. 20 gbps inbound and .2 gbps outbound (during that same timeframe as aforementioned actual inet links)

Numbers based on 21:00 CDT last night.


Hi Martijn and Josh,
Thank you for your detailed explanation. Let me explain my requirement so that you may help me better.According to PeeringDB, Charter (Access), Sprint (Transit), Amazon (Content) all three of them are ‘Balanced’. While, Cable One, an Access ISP says it is Heavy Inbound, while Akamai, Netflix (Content) are Heavy Outbound. On the other hand, Cox, another access ISP, it says that it is Mostly Inbound.
So, my question was more like to understand when an ISP decides to claim itself as any of these (Heavy Outbound/ Inbound or Balanced)? From an ISP’s own point of view, at what point, it says, my outbound:inbound is something, so I’m Heavy Outbound.
Please ignore my lack of knowledge in this area. I’m sorry I should’ve done a better job in formulating my question earlier.
Thank you.

my question was more like to understand when an ISP decides to claim itself as any of these (Heavy Outbound/ Inbound or Balanced)

Maybe I’m missing something but it’s as simple as looking at the interface graphs. We see a whole lot of green for inbound and a little little blue line for outbound. We are an ISP with residential and commercial customers.

Hi William,
Ha ha! Thanks for pointing that out. I’m not related to any ISP at all, so this is something new. I understand, PeeringDB is just a basic guideline and ISPs put their own information about their traffic ratios. I’m interested to know whether ISPs check their own accumulated traffic and then set their own outbound:inbound traffic ratios threshold to declare themselves as Heavy Outbound/ Inbound or Balanced. Or, is there some kind of rough understanding among networking community to treat certain ratios as Heavy/ Mostly Inbound/ Outbound.
Thank you.

That’s great. I’m assuming your traffic is mainly inbound. So, my question is, do you have a threshold that defines your traffic ratio type.
I’m taking an example from this thread. Say, your average incoming traffic is ~45 gbps, and outgoing traffic is ~4.5 gbps. So, your outbound:inbound = 1:10. What are you? Heavy Inbound?
Extending this example, if your ratio is 1:7 or 1:6, then, what would you claim to be? A ‘Mostly Inbound’? Or still call yourself as Heavy Inbound? I’m just trying to understand what is the community practice?
Thank you.

Thank you Aaron,
This is great. This gives an interesting insight regarding CDN as they seem to play a big role here. However, in general, what do you call your ISP as? A 'Heavy Inbound' or 'Mostly Inbound'? Is there any community standard about this ratio (having 1:10 or higher) to be treated as Heavy Inbound? Or this is just a rough estimation?

Thank you.

Seems you just have updated today. Thanks for letting us know.
Last time, I checked was yesterday and based on that I mentioned your traffic ratio being ‘Balanced’.

Prasun Kanti Dey
Ph.D. Candidate,
Dept of Electrical and Computer Engineering,
University of Central Florida

Yes, you seem to misunderstand (at least of what I understand). PeeringDB has categories of ratios to choose from. What has the community decided is acceptable ratios for each category? It’s fairly trivial for any network to determine what their ratio is as a number, but not necessarily as a PeeringDB label.

I’m heavy inbound. Which I think is characteristic of a stub-AS with lots of resi/busi bb … no transit… just a lot of people looking at stuff.

Inbound is of course from the perspective of traffic coming into my AS


Hi Prasun,

It was updated because ‘Balanced’ wasn’t accurate, we didn’t notice that’s what it said until you pointed it out, because it really don’t matter in the whole scheme of things. In regards to:

So, my question was more like to understand when an ISP decides to claim itself as any of these (Heavy Outbound/ Inbound or Balanced)? From an ISP’s own point of view, at what point, it says, my outbound:inbound is something, so I’m Heavy Outbound.

As a residential ISP, we are an eyeball network, we connect to the people using the content on the internet (of course with commercial customers also who host content, but mainly residential). Because of the nature of the users on our network, we are considered Heavy Inbound since most traffic will be going from content providers to users on our network. It’s really as simple as that, we do no calculation to figure out our traffic ratio and update according to some arbitrary ratio number, because none of that matters. That field in PeeringDB is used as additional information for someone who may look at the ASN and try to determine what to expect in general if connecting to them.

TL;DR - There are no hard numbers to give you, it just depends how someone feels that day of the week when setting it.

Hope this helps.

Thank you, Mike.
From an outsider, I don’t have any information of an ISP’s traffic numbers. And this may be confidential unless we are using any measurement platform, which CAIDA is doing. To get a rough idea about any ISP’s traffic outbound:inbound ratio I can only see it’s PeeringDB label. But, the question is whether there is any community decided values against these labels?
1:2 = Balanced
1:5 = Mostly Inbound
1:10 = Heavy Inbound
10:1 = Heavy Outbound
I just came up with these values. They don’t mean anything. I don’t have any solid evidence or source to support them. So, my question is, what people actually use? Or, it totally depends on the ISPs and they vary.

Thank you Aaron for confirming that. This is helpful.

Thank you Steller,
Your response is extremely helpful. I really appreciate your detailed explanation.
While I was looking for these numbers, I couldn’t find any. I thought, as an outsider, these numbers may not be accessible for me. And, as I don’t own an AS, so, I can’t be a member of PeeringDB! Instead I thought, why don’t I ask for your help directly to get a proper guidance. And, this discussion certainly helped me. Thank you again.
On a separate note, I’m happy that my mail drew your attention to update in the PeeringDB. Don’t know if it matters at all!

Pure ISP is heavy inbound. Pure hosting is heavy outbound.

The other categories are for people that have both types of business or who sell transit to both types of business. You are being asked what kind you are most.



ons. 19. jun. 2019 18.50 skrev Prasun Dey <>:

You’re right on that, Baldur. I’m aware of this, but my focus is to know whether there are any exact numbers that community has agreed on.
Thank you for your reply.