[arin-ppml] ARIN 2-Byte ASN inventory and issuance

Owen DeLong owen at delong.com
Mon Apr 11 20:09:03 EDT 2016

> On Apr 11, 2016, at 15:59 , Michel Py <michel at arneill-py.sacramento.ca.us> wrote:
>> Owen DeLong wrote :
>> However, if you have a configuration using extended communities and full support of modern ASNs enabled on
>> your router, then all ASNs are treated as 32-bit ASNs and there is no fundamental difference remaining.
> Big if, and in reality this is simply untrue. For large and /or heterogeneous networks, there will be a need to deal with both for quite a number of years. Event with compliant gear, there is always some legacy stuff somewhere else that has not been upgraded yet. Using extended communities is just the same as operating dual-stack : twice the number of things to manage, and a bridge to build between the old ones and the new ones.
> Two different configuration lines. Two sets of regexp to match. Limitations in extended communities that did not exist with the old ones.
> I gave examples recently. Show me in the real-world where old-style BGP communities have been completely deprecated.
> Moving to extended communities is time consuming, prone to mistakes, and not simple. Trying to argue that you can treat all AS numbers the same way is the same as trying to pretend that operating an IPv6-only network is simple. Let's not make with extended communities and 4-byte ASNs the same mistake we made with IPv6 : for the foreseeable future, we will have to deal with 2-byte ASNs, non-extended communities, and IPv4.

Operating an IPv6-only network is actually a lot simpler than operating an IPv4-capable network. The only draw-back being the inability to reach the fraction of the internet that has not yet deployed working IPv6.

I admit that today, that is a huge limitation for an IPv6-only network rendering doing so quite impractical, but as to the simplicity of doing so, that’s quite well established.

However, there’s a lot less of an issue with communities as there isn’t really an inability to reach providers that don’t support extended communities if you start using them.

> Here is the real question : do we want a grey market for 2-byte ASNs ? because as long as they are easier to use than 4-byte ones, there will be a value attached to them.

I’m simply not going to dignify another bogey-man argument.


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