Subject: [rbridge] Back to "what is the problem" for SVL/private VLAN/proxy ARP stuff

From: Radia.Perlman at sun.com (Radia Perlman)
Date: Tue, 03 Apr 2007 12:22:34 -0700

I think the reason we are all so confused is that we (especially me) do 
not understand what problem
we are solving. I wrote up in a previous note what I interpreted the 
problem to be. Let's be
really tangible about it. I'll start. Correct me if you disagree. But 
don't use reference to other solutions
or specs. It *can't* be that hard to actually describe it, rather than 
reference a spec, and without
being explicit people won't realize when they are thinking of different 
things.

So...is this the problem?

a) IP address block that has to be subdivided willy-nilly (not in clean 
sub-prefixes) among 4 customers

b) desire separation of the customers. I'd like this expanded. Why? Is 
it because of not wanting
to bother customer B with A's traffic, or that A doesn't want B to see 
A's traffic? Or both maybe.
Do we know what these applications are?

c) we want these communities to share some service node, say a DHCP 
server or an IP router

d) we don't want modify the IP router to do anything special (I suspect 
this is not really true, and that
the solutions people have in mind do require the IP router to know about 
this), or not much special

e) (I'm throwing this one in). We don't want to have to configure 
anything (RBridges or IP routers) to know
static mapping of IP addresses or MAC addresses to VLANs. The only 
configuration will be that an
RBridge (or bridge) will be configured to say "this set of ports of mine 
are VLAN A, this set are VLAN B, ..."
and it's by the tagging of packets transmitted from the port that other 
nodes learn which MAC addresses
(or which IP addresses) are in which VLAN

f) we want an IP endnode E_a in VLAN A to talk to an IP node E_b in VLAN 
B by being forwarded through the IP router. E_a and E_b are vanilla IP 
nodes and think they should be talking directly since they are in the same
IP address block.

g) maybe there are applications other than IP that want to have some 
sort of service node see all
the traffic from all the VLANs, and be able to talk to all the VLANs, 
but not have the VLANs talk to each
other. Is this true?

---

From: eric.gray at ericsson.com (Eric Gray (LO/EUS))
Date: Tue, 3 Apr 2007 16:17:11 -0500

Radia,

	I don't understand why you're asking this question.

	It is - believe it or not - sufficient to say "we're doing
it that way because we like to, and we can."

	Trying to analyze the specific problem that might, or might
not, be solved by using a specific technology is a mistake when
the technology is being used and nobody is especially interested 
in hearing how their problems might be solved a different way.

	I understand your frustration, but I don't see how getting
a grip on the problem is going to make any difference in what we
end up doing - so why waste our time on that particular subject?

--
Eric Gray
Principal Engineer
Ericsson  

> -----Original Message-----
> From: rbridge-bounces at postel.org 
> [mailto:rbridge-bounces at postel.org] On Behalf Of Radia Perlman
> Sent: Tuesday, April 03, 2007 3:23 PM
> To: rbridge at postel.org
> Subject: [rbridge] Back to "what is the problem" for 
> SVL/private VLAN/proxyARP stuff
> 
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