[netmod] Address Family versus Address Family

[tom petch <[e-mail]>]

I have always thought of Address Family as something that BGP created
and that others have used.  In fact, I find that there is an IANA
registry of Address Families which RFC8294 has turned into a YANG
module, but one using enumeration and not identity, which would seem to
limit its utility.

Indeed, while the lsr WG uses that module, I2RS does not with
 draft-ietf-i2rs-rib-data-model
defining
   identity address-family {description  "Base identity from which all
RIB      address families are derived.";  }

identity - good; RYO definition - um.

BGP also goes its own way with
  identity AFI_SAFI_TYPE { description
         "Base identity type for AFI,SAFI tuples for BGP-4";
       reference "RFC4760 - multi-protocol extensions for BGP-4";  }

And then there is RFC8349 with
  identity address-family {
    description  "Base identity from which identities describing address
          families are derived.";      }
and which defines ipv4 and ipv6, and which ties the concept firmly to a
RIB in a 1:1 correspondence.

When I raised this on the rtgwg list, the response was that the concept
of an address family is particular to a protocol, so there is no reason
for ospf and BGP to share anything, which is how it seems.

So, is there any reason for anyone to use the definition in RFC8349? or
the IANA module?

Tom Petch