Re: [Iotops] Automatically connecting to stub networks...

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Let's me see if I can dissect Ted's arguments against HNCMP in https://tools.ietf.org/html/draft-lemon-stub-networks-ps-00#section-1.3, and if restricting the problem to only allowing stub routers to be connected to a single router helps. (A topology with a single root router and a single level of branches).

1) HNCP only works if all routers in the AS runs it. It's a routing protocol so that's not surprising.
Solutions would have to either participate in routing and a prefix assignment protocol.
The degenerate case for routing is default route upstream and a static route for the assigned prefix downstream.
All traffic to sieblings would go via root router.

Ted also mentions that HNCP does not deal with the case where only a /64 has been delegated to the site.
In homenet we did a conscious choice of requiring a site to get enough addressing to get a /64 for each link.
I do know that the implementation in OpenWRT does support a single /64 (it subnets into /80s and does DHCP address assignment).
How to deal with a case of not enough addresses assigned is not a problem unique to HNCP though.

The degenerate case for addressing is:
a) Split up a /64 in pools of addresses for DHCP
b) If less than a /64 (e.g. already shared) then NAT

2) HNCP is too complex and does too much and is not implemented.
Not enough details to make any arguments for or against this one.
If one standard isn't deployed and implemented is a weak argument for inventing a new protocol and standardising that, that's neither specified, implemented nor deployed.


Question, what are the requirements here?

A) Stub network. Is it possible to restrict the topology to a single root/single level of leafes?
It prohibits multi-homing. What about the case where a node is attached to the stub with a hypervisor and VMs requiring addressing?
Is sending all traffic via the root acceptable? Instead of short-cutting between stub routers?

B) Is it possible to restrict the solution to the site having been delegated enough address space?
Or do you need to handle the cases where the site has:
a) not received enough /64s to number all links
b) have only been delegated a single /64
c) have only a shared /64
d) have only a single address


Cheers,
Ole