Re: [Softwires] ietf-softwire: IPv4 + PSID primary key for lw4over6 binding

Andy Wingo <> Tue, 12 July 2016 12:28 UTC

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From: Andy Wingo <>
To: Linhui Sun <>
References: <> <>
Date: Tue, 12 Jul 2016 14:28:30 +0200
In-Reply-To: <> (Linhui Sun's message of "Tue, 12 Jul 2016 19:40:18 +0800")
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Subject: Re: [Softwires] ietf-softwire: IPv4 + PSID primary key for lw4over6 binding
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Hi Lunhui,

Thank you for your feedback.  I am still developing my YANG instincts

On Tue 12 Jul 2016 13:40, Linhui Sun <> writes:

> [LH]: It seems that you think this would be the situation that an IPv6
> info of lwB4 is corresponding to two or more binding entries. I don't
> know why we need multiple IPv4 addresses for a single lwB4, but IMHO, if
> you do that you can also allocate multiple IPv6 addresses to the lwB4.
> By doing this, we can still have the guarantee that one IPv6 info is
> only mapping to an individual binding entry.

I believe that the use case goes more like this: you have a subscriber
who is allocated a small port set, and this is causing them probems;
they call to complain.  You could move them to an IPv4 address with more
ports per customer (and cause them to renew their lease, etc), or you
could just give them an additional potentially port-restricted
softwire.  This second case would make it useful to associate one B4
with multiple softwires.

I am not an operator however so I don't know how important this would
be.  Perhaps simply causing them to renew their lease is sufficient.