[rbridge] RBridge: a case of study
sgai at nuovasystems.com
Wed Oct 31 01:45:00 PDT 2007
I agree with Anoop answers
> -----Original Message-----
> From: Anoop Ghanwani [mailto:anoop at brocade.com]
> Sent: Tuesday, October 30, 2007 6:54 PM
> To: James Carlson; Silvano Gai
> Cc: Developing a hybrid router/bridge.; Radia.Perlman at Sun.COM
> Subject: RE: [rbridge] RBridge: a case of study
> > -----Original Message-----
> > From: rbridge-bounces at postel.org
> > [mailto:rbridge-bounces at postel.org] On Behalf Of James Carlson
> > Sent: Tuesday, October 30, 2007 2:37 PM
> > To: Silvano Gai
> > Cc: Developing a hybrid router/bridge.; Radia.Perlman at Sun.COM
> > Subject: Re: [rbridge] RBridge: a case of study
> > Silvano Gai writes:
> > > Radia,
> > >
> > > I have added few slides to the example and I suggest that
> > we use it as
> > > a possible case of study for TRILL (of course, not the only one).
> > >
> > > Let's see if the solutions we have discussed work on this example.
> > >
> > > The complete case of study is at:
> > >
> > > http://www.ip6.com/acme-example-v1.ppt
> > I have a few narrow questions that I think might help me
> > understand this picture a bit better. (I probably have more
> > questions once I know the narrow answers. ;-})
> Let me take a shot at answering these.
> > 1. After the proposed fix, should VLAN 3 on Cloud L be bridged
> > together with VLAN 3 on Cloud R, even though the backbone
> > doesn't directly carry VLAN 3? (I.e., are TRILL packets with
> > outer VLAN ID 7 or 8 and with inner VLAN 3 present on the
> > backbone?)
> Yes, that's pretty much what ends up happening.
> We have effectively extended the bridged LAN.
> > 2. What happened to the routing that once went on? It was
> > previously possible to route between these VLANs, but in the
> > diagram, it's not. Is routing between these networks
> > unimportant, or does it take place elsewhere, or must RBridges
> > both bridge and route in this scenario?
> Routing can continue to happen wherever it was happening.
> The Rbridge by itself doesn't do routing, but there's no
> reason why one cannot build a device that does bridging,
> RBridging, and routing.
> > 3. Suppose we were to configure VLAN 7 within Cloud L. Would you
> > expect H1 to be able to access nodes within the backbone Cloud
> > at that point? (I'm trying to figure out whether the "X" and
> > "Y" interfaces are of fundamentally different types or if the
> > RBridges are just bridges. I suspect they're different.)
> This is where I think would help to introduce some
> additional terminology in the spec. Just like MPLS
> LSRs have ingress, core, and egress functionality,
> I think we should have similar functions for RBridging.
> We could have access ports, trill ports and hybrid
> ports. From access ports, we only accept non-trill
> encap'ed frames, from trill ports, we accept only
> trill-encap'ed frames, and finally, from hybrid ports
> we accept either. Today we only allow hybrid ports
> and perhaps that's OK as a spec.
> Anyway, back to the specifics of your question: If you
> did configure VLAN 7 within cloud L, then the RBridges
> labeled "Router 1" and "Router 2" would have 2 of their
> ports configured to be on VLAN 7 and would simply bridge
> between those ports.
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