Company ASNs

[D. Strout]

As I've learned about networks and peering and such, I can't help but notice that some companies will have one ASN that they use for everything, while others will have several - sometimes in excess of half a dozen. For example, Hurricane Electric is AS6939. That's it. (Yeah, they also have AS6427, but they don't use it at all.) Google, on the other hand, has around 13 ASNs, though some are unused or gone entirely. My home ISP has ten, whereas Quadranet has two, with one unused. The trend seems to be more towards many ASNs, (Google, Level3, Cogent, etc.), but why? Why not save those numbers and keep everything in one place?

 

[MannDude]

Great question.

The answer: I have no idea.

Hoping someone comes along and hits us with some knowledge.

 

[texteditor]

Kinda depends on when they acquired their networks and how divided their network is.

 

[rds100]

Some used different ASes for different purposes - i.e. like a different AS for different continents. Some just bought / merged other networks. There are many reasons why a company could have multiple AS numbers.

 

[Wintereise]

Routing policies from NSP-grade providers are usually reliant on AS-sets instead of singular ASNs -- so to say they can have as many as they want.

As to why this is done, it's mainly to individualize a certain set of services from others -- or acquisitions; depends entirely on the situations of that particular company.

 

[concerto49]

Some have 1 ASN to hide the fact they don't have that much traffic / carriers over all locations.

E.g. maybe you have Cogent in Buffalo and TiNET in Chicago. You have 1 ASN that has Cogent AND TiNET - looks multi-home. Cool?

Quadranet's ASN works that way. Doesn't it look impressive? Colocrossing too.

Additional ASNs also cost money - minor but does.

Those that have multiple ASN actually do the right thing (if required) as it shows what they have per location.

Some that are big and have 1 ASN are because they can afford to have the exact same carriers in all locations and having 1 ASN is easier to manage.

End of day, most of it is marketing. See those that go, look at bgp.he.net and woah lots of carriers, when reality is different.

 

[RyanD]

Some that are big and have 1 ASN are because they can afford to have the exact same carriers in all locations and having 1 ASN is easier to manage.

End of day, most of it is marketing. See those that go, look at bgp.he.net and woah lots of carriers, when reality is different.

THIS^^

We have a few ASN from aqusitions and legacy networks, run a single ASN, 46562 on our primary network in all locations, we have the same carriers in virtually all locations, etc.

With coming any-cast and global load balanced services, it makes things significantly easier to manage

 

[vampireJ]

Ok sorry to take on the role of the troll- but how many ASNs do CC / CVPS have?

 

[concerto49]

Ok sorry to take on the role of the troll- but how many ASNs do CC / CVPS have?

1 for all locations.

 

[Deleted]

Route reflectors, easier to use MEDs/prefix lists based on default zone (big cities)

Just remember, SOME ASN's used to be OLD companies that were bought (adelphia <-> comcast)