Re: [Isis-wg] draft-noguchi-isis-protocol-topology-00.txt

 ] 
 ] 	So M-ISIS routers which follows draft-ietf-isis-ip-interoperable-00.txt
 ] 	section 13 MUST advertise IP Interface Address TLV
 ] 	if they want to make adjacent with legacy IPv4 routers on a LAN
 ] 	even if M-ISIS routers only support IPv6 IS-IS routing.
 ] 
 ] 	Is this correct?

correct. in specific, it's needed for those legacy IPv4 routers check
on those subnets(not all the legacy IPv4 routers do that).

 ] > as your neighbors. as far as i know, there is no ipv6 only routers yet,
 ] > get an ipv4 address on the LAN interface does not mean the router
 ] > need to switch ipv4 traffic, it can still be a ipv6 only M-ISIS node.
 ] 
 ] 	I don't think this is a good assumption.

please give one example of an existing "ipv6 only" router. we are talking
about transition, and legacy software does not stay forever. by the time
we see this kind of "ipv6 only" router widely used, we may not find those
legacy software based ipv4 routers around in networks.

but if you have to insert the "ipv6 only" router into the LAN which has a
mix of ip protocols, then:

 - have a knob in isis to maually inject an IPv4 address in the LAN IIH,
   only isis knows about this address internally. it's just software.
   ipv6 RFCs do not say it's illegal to type an ipv4 address inside
   an ipv6 only router.

 - upgrade the IPv4 only router software not to check the ipv4 subnet for
   ipv6 only neighbor, so it is not a "legacy" anymore.

 - don't put it into that LAN, ethernet is so cheap, setup another LAN.

thanks.

 ] 
 ] 	We are talking about "IPv6 only" IS-IS routers so we don't know
 ] 	the routers has IPv4 address on the interface or not.
 ] 
 ] 	If they don't have the IPv4 address on the interface, then
 ] 	how to encode the IP Interface Address TLV?
 ] 
 ] > for any new routing scheme, we can not expect a flag day to upgrage
 ] > all the nodes with new software. any scheme HAS to co-exist with the
 ] > current/legacy software. new software has the flexibility to do "tricks"
 ] > to work with the old software.

- Naiming
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