Hi,<br><br><div class="gmail_quote">On 18 September 2011 13:24, Usman Latif <span dir="ltr">&lt;<a href="mailto:osmankh@yahoo.com">osmankh@yahoo.com</a>&gt;</span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">

<div><div style="color:#000;background-color:#fff;font-family:arial, helvetica, sans-serif;font-size:10pt"><div><span>I sense the recommendations for /64 assignments even to residential users looks more political than technical.<br>

</span></div><div><br>
It seems that because end-hosts and other systems have already been 
built with more support for stateless autoconfig, this may act as a 
roadblock for us.</div><div><br><span></span></div><div><span>First of all, the RFC-6177 does not give the reasoning behind suggesting /64 as being technically motivated but more from the perspective of growth and scalability - I for one am having a hard time imagining how a &quot;residential site&quot; can grow to such a length that it would need 2^64 address space. ...<br>

</span></div></div></div></blockquote><div><br></div><div>For comparison, look at Netware IPX from the &#39;80s and &#39;90s.</div><div><a href="http://en.wikipedia.org/wiki/Internetwork_Packet_Exchange">http://en.wikipedia.org/wiki/Internetwork_Packet_Exchange</a></div>

<div><div>---</div><div>* Logical networks are assigned a unique 32-bit hexadecimal address in the range of 0x1 - 0xFFFFFFFE.</div><div>* Hosts have a 48-bit node address which by default is set to the network interface card&#39;s MAC address. The node address is appended to the network address to create a unique identifier for the host on the network.</div>

</div><div>---</div><div>32 + 48 = 80 bits c.f. IPv6&#39;s 128 bits.</div><div><br></div><div>Building an IPX network was simple because hosts auto-configured themselves.  No host counting or pre-registration required.</div>

<div>Joining 2 enterprise networks together was problematic because both sides would have used network &quot;1&quot;, &quot;2&quot; ... or &quot;A&quot; &quot;B&quot; ...</div><div><br></div><div>If you were to add 48 bits of Site IPv6 address to IPX you get 48 + 32 + 48 = 128 bits of address.</div>

<div>The split between subnet and host numbers is different from normal IPv6 48 + 16 + 64</div><div>... but network interface identifiers could grow from 48 to 64 bits (e.g. one-wire device ID)</div><div><br></div><div>I think that this shows that 64 bits is not overly excessive for host address number.</div>

<div><br></div><div>    John</div></div>