B. R.
Tina
http://tinatsou.weebly.com
On Nov 8, 2010, at 2:39 PM, Ole Troan wrote:
Tina,
Consider an operator facing a high subscriber growth rate. As a
result of this growth rate, the operator faces pressure on its
stock
of available public IPv4 addresses. For this reason, the
operator is
motivated to offer IPv6 access as quickly as possible.
The backbone network will be the first part of the operator's
network
to support IPv6. The metro network is not so easily upgraded to
support IPv6 since many devices need to be modified and there may
be
some impact to existing services. Thus any means of providing IPv6
access has to minimize the changes required to devices in the metro
network.
what is it that makes existing softwires mesh solutions unsuitable
for crossing the IPv4 only metro network? I'm thinking specifically
on 6PE or BGP tunnels.
Ole, thank you for asking. I didn't say that. IMHO, 6PE or BGP are
more appropriately used in core network. There are fewer uses of MPLS
in metro network. BGP tunnels are also more appropriate for core
network.
Essentially the authors are talking about a situation where 6rd is an
applicable technology, but needs modification to meet the constraints
of maximized savings of IPv4 addresses and no provider access to
customer site equipment. The IPv4 address savings occur only if the
customer site is IPv6-only, but the proposal still works for dual-
stack customer sites. The technical solution is to move the IPv6 in
IPv4 tunnel endpoint to the provider edge rather than have it in
equipment on the customer site, and use the provider gateway IPv4
address in the IPv6 prefix given to the customer site. As Ralph
pointed out, the protocol in RFC 5969 should be able to be applied
without change.
The authors will restructure the draft to illustrate this latter
point. As Ralph suggested, it will be submitted with the intention of
becoming an Informational describing an alternative deployment of 6rd
to meet the constraints we described above. I hope this plan meets
with the chairs' approval.
cheers,
Ole
In contrast to the situation described for basic 6rd [
RFC5569
], the
operator is assumed to be unable to manage IP devices on the
customer
premises. As a result, the operator cannot assume that any of
these
devices are capable of supporting 6rd.
If the customer equipment is in bridged mode and IPv6 is deployed to
sites via a Service Provider's (SP's) IPv4 network, the IPv6-only
host needs a IPv6 address to visit the IPv6 service. In this
scenario, 6to4 or 6RD can be used. However, each IPv6-only host
may
need one corresponding IPv4 address when using 6to4 or 6RD, which
brings great address pressure to the operators.
If the customer equipment is in routing mode
, the operator has an
opportunity to avoid assigning IPv4 addresses to sites running IPv6
only. Some other means is available for routing IPv6 traffic
through
the IPv4 network to that site.
This draft talks about "Some other means".
B. R.
Tina
http://tinatsou.weebly.com
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