[rbridge] Use of 802.1ah Encaps

[Don Fedyk]

Hi Eric 

> -----Original Message-----
> From: Gray, Eric [mailto:Eric.Gray at marconi.com] 
> 
> Ali/Don,
> 
> 	The use of 802.1ah encapsulation does not intuitively 
> suggest itself in the TRILL problem domain for at least two
> reasons:
> 
> 1)	Provider Back-bone Bridging intuitively seems out of
> 	place in solutions aimed at enterprise networks - and
> 	this would seem to be even more true for solutions 
> 	aimed at "plug-and-play" applicability.
Hmmm Trill spent 1.5 years coming up with a header that looks remarkably
like 802.1ah. A fact many of us have pointed out before.  If you are
using an IEEE 802.1 Ethernet data plane your baseline choices are 802.1Q
or 802.1ah. 

> 
> 2)	Use of 802.1ah encapsulation assumes "bridging" of the
> 	tunneled frame transparently from edge-to-edge - and
> 	this would seem to go counter to the idea of using a
> 	link-state routing protocol for shortest path routing
> 	of MAC frames.
Encapsulation and the use of link state are orthogonal concepts so I
disagree. 

> 
> 	That said, the minute that we start suggesting that an 
> enterprise is large enough to require using service provider
> (like) solutions (in particular, requiring a substantial 
> back-bone capacity, and assuming static configuration as a 
> means to ensure deterministic network behavior) - OR that we 
> might in fact use some form of spanning tree forwarding - it 
> then becomes clear that we should consider using 802.1ah.  It 
> is certainly the case that we should not be defining another 
> Ethernet encapsulation explicitly to solve the same problem.

What we should be worried about is solutions for commoditized
encapsulated header. Ethernet has benefited in the past by having a wide
applicability: enterprise to carrier for chips and software that were
produced.  

Regards,
Don 


> 
> --
> Eric
> 
> > -----Original Message-----
> > From: rbridge-bounces at postel.org 
> > [mailto:rbridge-bounces at postel.org] On Behalf Of Ali 
> Sajassi (sajassi)
> > Sent: Wednesday, December 06, 2006 2:39 AM
> > To: Don Fedyk; Developing a hybrid router/bridge.
> > Subject: Re: [rbridge] Draft minutes posted
> > 
> >  
> > 
> > 
> > Yes, if there is any reason as to why .1ah encap cannot be 
> > used, then I
> > would like to hear it.
> > 
> > -Ali 
> > 
> > 
> > 
> > > -----Original Message-----
> > > From: rbridge-bounces at postel.org 
> > > [mailto:rbridge-bounces at postel.org] On Behalf Of Don Fedyk
> > > Sent: Tuesday, December 05, 2006 10:17 AM
> > > To: Developing a hybrid router/bridge.
> > > Subject: Re: [rbridge] Draft minutes posted
> > > 
> > > Hi Erik
> > > 
> > > In the minutes: 
> > > 802.1ah header synergy?  On this point myself, and I recall 
> > > Ali Sajassi and Donald Oconnor all stood up and said that 
> > > 802.1ah is going to be a standard encapsulation header. My 
> > > point was Trill should see what it could deliver on this 
> > > encapsulation before inventing similar but different headers.
> > > 
> > > Regards,
> > > Don  
> > > 
> > > > -----Original Message-----
> > > > From: rbridge-bounces at postel.org
> > > > At http://www3.ietf.org/proceedings/06nov/minutes/trill.txt
> > > > 
> > > > Any corrections?
> > > > 
> > > >     Erik