Subject: (ngtrans) questions on SIIT

From: Kazu Yamamoto (山本和彦) <[email-masked]>
Date: Thu, 13 Jan 2000 19:34:37 +0900

I have two questions on the motivation of SIIT. The 08 ID says:

---
   However, there are other potential solutions in this area:
  (1) If there is no IPv4 routing inside the network i.e., the cloud
      that contains the new devices, some possible solutions are to
      either use the translators specified in this document at the
      boundary of the cloud, or to use Application Layer Gateways (ALG)
      on dual nodes at the cloud's boundary.  The ALG solution is less
      flexible in that it is application protocol specific and it is
      also less robust since an ALG box is likely to be a single point
      of failure for a connection using that box.

  (2) Otherwise, if IPv4 routing is supported inside the cloud and the
      implementations support both IPv6 and IPv4 it might suffice to
      have a mechanism for allocating a temporary address IPv4 and use
      IPv4 end to end when communicating with IPv4-only nodes.  However,
      it would seem that such a solution would require the pool of
      temporary IPv4 addresses to be partitioned across all the subnets
      in the cloud which would either require a larger pool of IPv4
      addresses or result in cases where communication would fail due to
      no available IPv4 address for the node's subnet.
---

(Q1) When we provide "a mechanism for providing routing (perhaps using
*IPv6* in IPv6 tunneling)" for SIIT, isn't it a single point of
failure?  So, is the observation (1) appropriate?

(Q2) Let's consider "a mechanism for allocating a temporary address
IPv4 and use IPv4 end to end when communicating with IPv4-only nodes"
in (2).

Suppose that we provide both "a mechanism for the IPv6-only node to
somehow acquire a temporary IPv4 address" and "a mechanism for
providing routing (perhaps using *IPv4* in IPv6 tunneling)" for this
mechanism.

In this case, is the observation (2) appropriate? I think this can
solve the routing problem described in (2).

--Kazu