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On 2/8/2011 8:46 PM, Lee Howard wrote:
<blockquote cite="mid:381659.9803.qm@web63301.mail.re1.yahoo.com"
type="cite">
<pre wrap="">
John, Tony, you are saying, "There is no way to avoid extensive deployment of
large-scale NAT44 in ISP networks"?
I have a hard time accepting that, since nobody wants it. It runs contrary to
everyone's interest. It is a temporary solution at best, so companies have to
deal with both LSN and IPv6, instead of just IPv6. Is everyone really resigned
to this?
</pre>
</blockquote>
<br>
This isn't universal, but there will be significant amounts of
NAT(of various flavors) in ISP networks, especially telco networks.
There are as many issues with infrastructure gear as there are with
customer side equipment and largely for the exact same reasons
(economics). This is especially true of telco based networks since
in many cases the equipment has been in place for a decade or so and
has been EoL'ed for >=5 years. This _shouldn't_ be a problem but
is because someone involved in earlier DSLAM design decided that any
IPv6 traffic must be from bogons and decided to drop any frames with
IPv6 (<span class="Apple-style-span" style="border-collapse:
separate; color: rgb(0, 0, 0); font-family: sans-serif; font-size:
16px; font-style: normal; font-variant: normal; font-weight:
normal; letter-spacing: normal; line-height: normal; orphans: 2;
text-indent: 0px; text-transform: none; white-space: normal;
widows: 2; word-spacing: 0px;"><span class="Apple-style-span"
style="border-collapse: collapse; font-family:
monospace,'Courier New'; font-size: 13px; line-height: 19px;">0x86DD)
in the EtherType field. Whoever first made the decision at this
point doesn't matter because that was copied by several
different manufacturers so now there a ton of DSLAMs (and I
suspect early PON FTTx gear) that simply won't pass layer 2
frames carrying IPv6 traffic unless its tunneled over 4. Whats
worse because the gear is so old there isn't a firmware/software
fix available and in most cases simply won't be. This doesn't
include problems with DSL modems, most of which are routers,
which can't be upgraded remotely (if there is an upgrade) unless
the telco was very forward thinking and implemented TR-069.
This also doesn't include the fact that some of the most common
lines of PPoE/oA termination devices (Redback SMS line and AFAIK
Nortel Shasta lines) don't have an upgrade path. Redback (now
owned by Ericsson) gleefully points providers to their new line
of gear (SmartEdge line) if they want IPv6 functionality. <br>
<br>
The equipment cost for one _small_ telco, ~3,000 DSL ports, can
easily exceed $1.75 million and that doesn't count the time and
expense (and customer disruption) to actually replace the gear.
If they have to replace modems on a large scale the cost will be
at least triple that. That means as the squeeze for IPv4
addresses starts to bite the cost for doing CGNAT is far less
than trying to actually fix the problem and the vendors at least
are claiming that most end users won't notice.<br>
</span></span>
<pre class="moz-signature" cols="72">--
Scott Helms
Vice President of Technology
ISP Alliance, Inc. DBA ZCorum
(678) 507-5000
--------------------------------
<a class="moz-txt-link-freetext" href="http://twitter.com/kscotthelms">http://twitter.com/kscotthelms</a>
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