Re: [rprsg] (Terms & Defn) topology terms
Bob,
Should it not be possible to preclude the addition of ingress traffic until such
a time as a new station has been provisioned? I believe that some companies wish
to do this.
Using transit is fine by me, I do think it will lead to confusion with transmit.
They are both very similar visually and audibly. However, I have no problem
changing to use whatever term the group decides is best.
Thanks,
Allan.
Bob Sultan wrote:
>
> Brian, Allan,
>
> I agree that the disruption time should not be specified. Using the definition I suggested as a base,
> this would leave us with:
>
> plug-and-play: The property that a station be operational some time after physical insertion of the
> station into the ring and power-on of the station, without a requirement for explicit station
> provisioning or configuration .
>
> Allan,
>
> I think it simplifies the definition to use the separately defined term 'operational'. I'm not sure why
> the work 'optional' is needed for ingress traffic (although I do remember that this was discussed in the
> meeting). If the station has ingress traffic and there is a default provisioning and the traffic is
> consistent with that provisioning, then I would assume that an operational station would transmit that
> traffic consistent with the rules for ingress traffic. Also, I normally expect that a plug-and-play
> device would be fully operational with respect to control activities (not just the ability to insert
> control messages).
>
> Your posting raises another terminology issue. You refer to 'tandem' traffic, rather than 'transit'
> traffic. The term 'tandem' has the advantage that it is less likely to be mistaken for the term
> 'transmit' than is the case with 'transit'. On the other hand, 'transit' seems more descriptive and
> 'tandem' has an association with telephony.. This is clearly a key term, how do others in the group
> feel about this?
>
> Bob
>
> Allan Pepper wrote:
>
> > Brian, Bob,
> >
> > I would prefer a definition for plug and play that avoids mentioning specific times for protection
> > switching caused by inserting a station into a ring.
> >
> > The original intent of the term plug and play was to indicate that a new station could be inserted
> > and pass tandem frames, insert control frames, and optionally insert data frames without any
> > operator
> > provisioning.
> >
> > Including Brian's suggestion, this would make the definition for plug-and-play:
> > The property that a station be able to recieve and transmit tandem frames (and optionally insert
> > data
> > frames) some time after physical insertion of the station into the ring and power-on of the station,
> > without a requirement for explicit station provisioning or configuration.
> >
> > Thanks,
> > Allan Pepper
> >
> > Brian Holden wrote:
> > >
> > > Bob,
> > >
> > > Good definitions.
> > >
> > > The phrase "without disruption to transit traffic" in your definition of plug-and-play is TBD in
> > > the standard. Unless we add specific capabilities in the standard, it is likely that there will
> > > be at least 50 ms of disruption when you break the ring to put a new station in, and maybe more
> > > when the ring is restored. Your definition can be changed to reflect the current state of the
> > > motions by just dropping the words "without disruption to transit traffic and". Another
> > > possibility is to change "without disruption" to "with minimal disruption" - either works for me.
> > >
> > > Thanks,
> > > Brian H.
> > >
> > >
> > >
> > > _______________________________________________
> > > Brian Holden PMC-Sierra, Inc.
> > > 3975 Freedom Circle, Santa Clara CA USA
> > > +1.408.239.8123 Fax +1.408.492.9862
> > > brian_holden@xxxxxxxxxxxxxx http://www.pmc-sierra.com
> > >
> > > -----Original Message-----
> > > From: Bob Sultan [mailto:Bob.Sultan@xxxxxxxxxxxxxxx]
> > > Sent: Wednesday, May 23, 2001 8:30 AM
> > > To: stds-802-rprsg@xxxxxxxx
> > > Subject: Re: [rprsg] (Terms & Defn) topology terms
> > >
> > > Brian,
> > >
> > > I added your definition of plug-and-play to a new category called 'activation'. I also
> > > added my own alternative, and a definition of 'operational' used in that definition.
> > >
> > > activation
> > > plug-and-play : (Alt. 1) The requirement that a station be capable of Topology
> > > Discovery and optional insertion and drop of user frames without manual intervention
> > > other than the physical connection of the equipment .
> > > (Alt. 2) The property that a station be operational some time after physical insertion
> > > of the station into the ring and power-on of the station, without disruption to transit
> > > traffic and without a requirement for explicit station provisioning or configuration .
> > >
> > > operational : The state of a station in which it transits traffic, inserts traffic consistent
> > > with explicit or default provisioning, copies and/or strips traffic destined for the station, and
> > > performs control activities associated with the steady-state.
> > >
> > > I modified 'topology database' and added 'topology discovery':
> > > topology/routing
> > > topology database : A representation of the connectivity and capabilities of stations and links
> > > on the ring.
> > > topology discovery : The process by which the connectivity and capabilities of the stations and
> > > links on the ring is discovered by a newly added station.
> > > protection (resilience)
> > > I replaced the definitions of steering and wrapping:
> > >
> > > steering: Placement of a frame on the outer ring or inner ring at the ingress data-station based
> > > on knowledge of the ring topology . Steering provides resiliency by directing frames on a path
> > > that does not transit a failed transmission link or node.
> > >
> > > wrapping: The transit of a frame such that it is received on one transmission ring and
> > > retransmitted on the opposing ring. Wrapping provides resiliency by allowing traffic to bypass a
> > > failed transmission link or node on the ring.
> > >
> > > steering : The placement of a frame on a specific ringlet at the ingress station based on
> > > knowledge of the ring topology .
> > >
> > > wrapping: The transit of a frame such that the frame is received on one ringlet and retransmitted
> > > on the opposing ringlet . (footnote: The definition describes the case of a dual-ring as agreed
> > > in the May meeting. In the case of a multi-ring, this might be changed to 'an opposing ringlet' or
> > > 'a different (or alternate) ringlet'. It might also be unchanged, depending on what is considered
> > > to be a useful definition of wrapping in the multi-ring environment.)
> > >
> > > Keep those definitions coming, I will repost the doc after we have some more.
> > > Bob
> > >
> > >
> > > Brian Holden wrote:
> > >
> > > > How about:
> > > >
> > > > Topology Database: A representation of the connectivity and capabilities of the stations and
> > > > links on the ring.
> > > >
> > > > (Inevitably we will end up with at least one bit of standards-based optional capability which
> > > > will need to be stored in the database.)
> > > >
> > > > Topology Discovery: The process by which the connectivity and capabilities of the stations and
> > > > links on the ring is discovered by a newly added station.
> > > >
> > > > and a new one from the motions
> > > >
> > > > Plug and Play: The requirement that a station be capable of Topology Discovery and optional
> > > > insertion and drop of user frames without manual intervention other than the physical connection
> > > > of the equipment.
> > > >
> > > > Brian H.
> > > >
> > > > _______________________________________________
> > > > Brian Holden PMC-Sierra, Inc.
> > > > 3975 Freedom Circle, Santa Clara CA USA
> > > > +1.408.239.8123 Fax +1.408.492.9862
> > > > brian_holden@xxxxxxxxxxxxxx http://www.pmc-sierra.com
> > > >
> > > > -----Original Message-----
> > > > From: Bob Sultan [mailto:Bob.Sultan@xxxxxxxxxxxxxxx]
> > > > Sent: Tuesday, May 22, 2001 3:17 PM
> > > > To: stds-802-rprsg@xxxxxxxx
> > > > Cc: Allan Pepper; Brian Holden
> > > > Subject: Re: [rprsg] (Terms & Defn) In definitions of steering and
> > > > wrapping s/b ringl ets instead of rings
> > > >
> > > > Brian,
> > > > I agree with your corrections, but we probably need to correct these further.
> > > >
> > > > Allan,
> > > > After seeing Brian's email, but before seeing your email, I made a nearly
> > > > identical correction. I omitted the words 'and link failures' as I assumed that
> > > > 'ring topology' means 'current ring topology' and already includes any failed
> > > > links. Let me know if you disagree.
> > > >
> > > > Wrapping is more interesting. In the case of a dual-ring, 'different ringlet'
> > > > and 'opposing ringlet' would have the same meaning. So, if the definition is
> > > > specific to a dual-ring, I prefer 'opposing ringlet'. I think you intended your
> > > > definition to be sufficiently general to cover the multi-ring case. The
> > > > definition would allow 'wrapping' by shifting frames from one clockwise ringlet
> > > > to another clockwise ringlet. This could be exactly what people have in mind for
> > > > wrapping on a multi-ring, but I'm not sure.
> > > >
> > > > So, should our definitions be specific to the dual-ring case (and we could update
> > > > them if the standard includes multi-rings) or should they all be sufficiently
> > > > general to include the multi-ring case (and we could update them to make them
> > > > specific to the dual-ring case if multi-rings are not supported)? My bias is
> > > > towards describing the dual-ring case (but it is a bias).
> > > >
> > > > If we define our terms based on a multi-ring, I think I would need some
> > > > understanding of how steering, wrapping, discovery, etc. are described in the
> > > > multi-ring environment. If someone thinks we should define terms general enough
> > > > for a multi-ring, can that person volunteer a description of how this works?
> > > >
> > > > Bob
> > > >
> > > > Allan Pepper wrote:
> > > >
> > > > > I belive the term node should also be replced with station. Additionaly, the
> > > > > definition does not need to explain why the mechanism works. These changes
> > > > > would make the following definitions.
> > > > >
> > > > > steering: placement of a frame on a ringlet by the ingress station based on
> > > > > knowledge of ring topology and link failures.
> > > > >
> > > > > wrapping: the transit of a frame such that is is received by a station on one
> > > > > ringlet and re-transmitted on a different ringlet.
> > > > >
> > > > > Thanks,
> > > > > Allan Pepper
> > > > > Nortel Networks
> > > > >
> > > > > Brian Holden wrote:
> > > > > >
> > > > > > Bob, Group,
> > > > > >
> > > > > > In the definitions of Steering and Wrapping, the
> > > > > > word "ring" should be replaced by "ringlet" except in
> > > > > > the phrases "ring topology" and "node on the ring".
> > > > > > The phrase "node on the ring" could also be replaced
> > > > > > by "node".
> > > > > >
> > > > > > Thanks,
> > > > > > Brian H.
> > > > > >
> > > > > > _______________________________________________
> > > > > > Brian Holden PMC-Sierra, Inc.
> > > > > > 3975 Freedom Circle, Santa Clara CA USA
> > > > > > +1.408.239.8123 Fax +1.408.492.9862
> > > > > > brian_holden@xxxxxxxxxxxxxx http://www.pmc-sierra.com
> > > >