For broadband services in Metro Networks, MPLS or BGP tunnel will
cause too much cost. So they are not widely used for broadband services.
But ISPs may provide MPLS or BGP tunnel for enterprise users.
B. R.
Tina
http://tinatsou.weebly.com
On Nov 8, 2010, at 6:53 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.
1) is BGP tunneling not applicable because these devices don't
support BGP? or not support MPLS?
2) my concern with using 6rd for this purpose is that while
automatic tunneling by encoding the tunnel end point in the payload
address is convenient. offering a 'sensible' sized IPv6 prefix to
end users is going to be problematic. note this is purely a concern
from a deployment perspective. I have no doubt that you can _use_
6rd this way. just because we _can_, _should_ we?
can you give some examples of how you deliver e.g. /56 or /64 to end
users, using gi-6rd? (without expecting the SP to have a /16 of v6
space obviously).
cheers,
Ole
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