[rbridge] RBridge: a case of study

[Zhi-Hern Loh]

Donald,

In addition to Eric's questions, could you (or anyone else) explain what would happen in the following scenario?

Toplogy:

                RBa
                /
              VID a
               /
   RBn-link X-----VID b------RBb

Problem:

  RBn is connected to 2 VLANs on link/port X. Connectivity to RBa is via VLAN a, and connectivity to RBb is via VLAN b.

  Suppose that RBa and RBb are in the multi-destination distribution tree from RBn. For a multi-destination frame going out link/port X on RBn to RBa and RBb, what is the VID on the outer VLAN tag? Or could there be need to send 2 frames, one with VID a and another with VID b?



Thanks,
Hern
Fulcrum Microsystems


----- Original Message -----
From: "Eric Gray" <eric.gray at ericsson.com>
To: "Eastlake III Donald-LDE008" <Donald.Eastlake at motorola.com>, "Zhi-Hern Loh" <zloh at fulcrummicro.com>
Cc: "Developing a hybrid router/bridge." <rbridge at postel.org>
Sent: Wednesday, October 31, 2007 4:16:33 AM (GMT-0800) America/Los_Angeles
Subject: RE: [rbridge] RBridge: a case of study

Donald,

	When you say "would all have the same Outer [VID]"
- do you mean:

1) all frames MUST have the same VID within the an RBridge 
   campus, 
2) all frames forwarded from a (physical) port on one RBridge 
   to a (physical) port on another RBridge MUST have the same
   VID, or 
3) something else?

--
Eric Gray
Principal Engineer
Ericsson  

> -----Original Message-----
> From: rbridge-bounces at postel.org 
> [mailto:rbridge-bounces at postel.org] On Behalf Of Eastlake III 
> Donald-LDE008
> Sent: Wednesday, October 31, 2007 12:22 AM
> To: Zhi-Hern Loh
> Cc: Developing a hybrid router/bridge.
> Subject: Re: [rbridge] RBridge: a case of study
> 
> Hi,
> 
> Yes, as noted in protocol draft -05, the pseudo code was 
> unchanged from
> -04 and is out of date.
> 
> As currently being discussed, the TRILL encapsulated data being
> forwarded out a particular physical port would all have the same Outer
> VLAN ID.
> 
> Thanks,
> Donald
> 
> -----Original Message-----
> From: rbridge-bounces at postel.org 
> [mailto:rbridge-bounces at postel.org] On
> Behalf Of Zhi-Hern Loh
> Sent: Tuesday, October 30, 2007 10:54 PM
> To: Anoop Ghanwani
> Cc: Developing a hybrid router/bridge.; Radia Perlman; James Carlson
> Subject: Re: [rbridge] RBridge: a case of study
> 
> 
> ----- "Anoop Ghanwani" <anoop at brocade.com> wrote:
> > > -----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
> > itself
> > >       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.
> > 
> 
> Anoop, I'm reading the RBridge protocol specification version 5 and it
> seems to me that your comment is inconsistent with the spec. 
> In section,
> 5.2.2.3, the spec says that the outer VLAN tag of TRILL data 
> frames has
> the same VID as the inner tag. Is this section going to be changed?
> 
> Futhermore, if we were to use different VIDs on outer VLAN 
> tags then we
> would need to handle the multi-destination case where one 
> would need to
> send a multi-destination frame per outer VID to communicate 
> with the RBs
> in the distribution tree which are using different VIDs. Is this
> correct?
> 
> Thanks,
> Hern
> Fulcrum Microsystems
> 
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