how many BGP routers, how many ASes

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1

Hi all,

I have scouted around for this information, but not get very far. I'm
hoping someone will have answers at hand.

What I want to know is roughly how many :

1. ASes there are in the world today?
2. BGP routers there are, for intra-domain as well as inter-domain routing,
in total in the world?
3. BGP routers do the largest ASes have?

Really interesting would then be to say either how fast the above numbers
are growing, or to give estimates for what the answers to 1-3 will be in 5
years time.

An Internet source that provides the above information would be most useful
- though I can't seem to find it with google.

I'd be grateful for answer to be sent to me directly, whether you also post
to NANOG is up to you.

thanks in advance.

irfan

2

Hi Irfan,

Take a look at the Team Cymru page here:
http://www.cymru.com/BGP/summary.html

Thanks,
John

3

You obviously didn't look very hard. The answer to the first question is posted to this very list every Friday:

    <http://www.cidr-report.org/as2.0/>

The last two are probably not really knowable with any precision, but you might find some estimates. Although I'm not really sure what utility the number is.

4

Irfan,

This is sent weekly to the list:

Routing Table Report 04:00 +10GMT Sat 09 May, 2009

Report Website: http://thyme.apnic.net
Detailed Analysis: http://thyme.apnic.net/current/

Analysis Summary

5

The weekly routing table summary posted here will give you a good approximation,
but it does not include AS's that aren't announced on the public Internet. This
may or may not be an issue, depending what you are doing with the numbers (for
instance, allocated but not announced ASs may not matter if you're looking at
BGP performance - but they *do* matter if you're trying to estimate a drop-dead
date for 32-bit ASN deployment).

6

What I want to know is roughly how many :

1. ASes there are in the world today?

Hi Irfan,

A little over 31,000. See http://www.cidr-report.org/as2.0/

2. BGP routers there are, for intra-domain as well as inter-domain routing,
in total in the world?

I know of no authoritative source for this information. I used 150k
for my estimate when I prepared
http://bill.herrin.us/network/bgpcost.html last year; that fell more
or less in the middle of the educated guesses I got here on nanog and
in the other places I asked.

Figure every AS must have at least one BGP router, the vast majority
will have at least two, many will have more than two, and at least
some will have more than 100. Figure also that there are fewer BGP
routers in use than there are prefixes in the table. Gives you a lower
bound of around 70k and an upper bound around 290k.

3. BGP routers do the largest ASes have?

Decide what you mean by largest, identify which AS that is on the CIDR
report and then go ask them.

Really interesting would then be to say either how fast the above numbers
are growing, or to give estimates for what the answers to 1-3 will be in 5
years time.

http://www.potaroo.net/tools/asn32/
Figure 7 offers a handy graph from which you should be able to project a trend.

Regards,
Bill Herrin

7

you might want to have a look at:
http://irl.cs.ucla.edu/topology

--Ricardo

8

How are you certain that there are fewer BGP routers than prefixes?

At all my previous employers we have had more routers than prefixes we advertised to the global table (which is where you get your 290k number).

9

Wow, wish *I* had a group of people willing to do my thesis paper research
for me ..