RE: [EFM] OAM - Faye's seven points
Faye,
Unless you get a bit error that "garbages" an octet, once a message is
encoded and transmitted, it does not get dropped while it is in the
link. Full duplex does not even have to worry about collisions. If the
OAM messaging is in an "out-of-band" channel there is not even the conflict
of competing with the data stream for insertion. There is no need for
priority queuing of the OAM messages in that type of PHY.
At 04:54 PM 9/18/01 -0700, Faye Ly wrote:
>Geoff,
>
>Some OAM traffic is more critical than others. For example -
>
>OAM command like 'reset' (in our case, reset CPE) should not be
>retried. Certainly don't want to reset the CPE a couple of times
>just because network is slow. Giving up means sending a technician
>to the field to actually toggle the power button on the CPE. This
>is very expensive. The whole reason of requesting for a dedicated
>OAM channel/IPG/whatever is to gurantee that no acutal human
>needs to be sent to the field. Maybe this is not do-able but we
>ought to try our best.
>
>On a side note -
>
>Can you please clarify the statement "P2P PHYs do not drop packets"?
>This is good. I don't need to keep all those dropped packets/bytes
>error counters then. Thanks.
>
>-faye
>
>
> : Geoff Thompson
> Sent: Tue 9/18/2001 2:38 PM
> To: bob.barrett
> Cc: Faye Ly; Geoff Thompson; fkittred; stds-802-3-efm
> Subject: RE: [EFM] OAM - Faye's seven points
>
>
> Bob-
>
> At 11:25 AM 9/18/01 +0100, Bob Barrett wrote:
>
>
> Faye,
>
> I think your re-stating these seven points is very
>timely. If we were at a
> meeting I would suggest that we had a straw poll on each
>of them. I would
> add an eighth i.e.
>
> 8. What kind of OAM&P traffic requires guaranteed
>delivery?
>
>
> 1) We don't do "P". We have already agreed that provisioning is
>declared to be outside our scope
> 2) There is no such thing as guaranteed delivery
> 3) P2P PHYs do not drop packets
> 4) Properly designed CSMA/CD LANs do not lose packets. At worst
>they try to send for awhile and if they don't get through they give up.
>
> Geoff
>
>
>
>
> Short answer: All of it.
>
> Slight need for clarification: Bob Barrett (me) is an
>equipment designer,
> not a service provider. I just happen to have been
>designing and selling
> access equipment for the past ten years, rather than
>enterprise equipment. I
> learnt about the OAM needs of my customers the hard way,
>by building-in what
> I thought were reasonable OAM systems and then being
>advised that I had not
> got it quite right (and they don't buy what is not quite
>right).
> Nevertheless, I will answer the seven points as I see
>them, see below,
>
> Bob Barrett
>
> > -----Original Message-----
> > From: Faye Ly [mailto:faye@xxxxxxxxxx]
> > Sent: 17 September 2001 18:32
> > To: bob.barrett@xxxxxxxxxxxxxxx; Geoff Thompson;
>fkittred@xxxxxxx
> > Cc: stds-802-3-efm@ieee.org
> > Subject: RE: [EFM] OAM developing Geoff's observation.
> >
> >
> > Bob,
> >
> > This largely depends on the requirements. What kind
>of OAM&P traffic
> > requires
> > guaranteed delivery? And also what kind of
>intelligence we require from
> > the
> > CPE and still maintain the low cost. If you can tell
>me what is the
> > requirements
> > for each of the OAM&P traffic listed below: (This is
>the minimum list
> > of
> > OAM&P traffic I can think of)
> >
> > 1. Reset command
>
> Mandatory
>
> > 2. Link failure/status
>
> Mandatory
>
> > 3. CPE registration or inventory (The former is the
>action and the later
> > is
> > the results).
>
> Some form of registration, even if it is operator driven
>is mandatory.
> Auto registration is desirable.
>
> > 4. Connectivity diagnose (ping etc) - This is divided
>into link
> > connectivity which
> > can be covered by 2 and subscriber line connectivity.
>
> Mandatory for the link, up to a point as close to the
>subscriber interface
> as possible e.g. copper loop back on the connector side
>of the IC, in the
> last output stage of the IC (most PHY ICs support this
>already).
>
> Tests to the subscriber equipment are outside of the
>scope of EFM, but in
> real terms the service provider will probably PING
>something on the
> subscriber network, given access rights.
>
> > 5. Subscriber activation and deactivation (or
>generally referred to as
> > provisioning)
>
> Mandatory - at the level of EFM this is probably no more
>then turning a
> subscriber port on and off, and may be changing an
>interface from 10M to
> 100M to 1GE. Anything else is above the scope of EFM I
>would think.
>
> > 6. CPE maintanence (upgrade, backup ...)
>
> Desirable - possibly an area where EFM defines a cooms
>channel but not the
> protocol or methodology that vendors implement over it
>????
>
> > 7. Accounting information on the subscriber line -
>optional since some
> > of
> > the accounting data is actually collected at the
>aggregated box.
>
> I agree that this function is not required within the
>CPE. However, RMON
> type stats might be useful within the CPE as history for
>diagnostics, but
> not required as a source of relable data for billing
>information. I think
> this will be a vendor specific thing. The existing
>standards define what can
> be done. The vendors will choose what they implement.
>The customers will
> choose equipment that has the right balance of features
>and commercial terms
> for them.
>
> >
> > This will be really helpful for the vendors that are
>building these
> > equipements
> > to justify for the need or the size of a dedicated
>OAM&P channel.
>
> Sometimes as vendors we have to make inspired guesses
>:-).
>
> On Sanjeev Mahalawat's point in an email to/from Faye -
>I think it is highly
> desirable that some form of head-end proxy server is
>used to translate the
> rather complex management requirements of the NOC NMS
>systems into simpler
> commands for the EFM systems. And also take simple alarm
>and status messages
> from EFM CPE and create SNMP traps and browser pages for
>the human
> interface. Consolidating the 'presentation intelligence
>and processing' in a
> head end proxy server shares the cost of the engine
>across multiple CPE
> nodes. The CPE needs only a micro-controller (or less),
>rather than an
> engine with a full IP stack. Low cost embedded JAVA
>processors are coming,
> but they are taking their time :-).
>
> The EFM technical point is:
>
> 'keep EFM OAM simple; vendors can implement the cleaver
>stuff; economically
> this will probably at the head end; there is an
>opportunity for silicon to
> do this at the CPE end, but that may take a while'.
>
> Bob Barrett
>
> > -faye
> >
> > -----Original Message-----
> > From: Bob Barrett [mailto:bob.barrett@xxxxxxxxxxxxxxx]
> > Sent: Saturday, September 15, 2001 5:36 AM
> > To: Geoff Thompson; fkittred@xxxxxxx
> > Cc: stds-802-3-efm@ieee.org
> > Subject: RE: [EFM] OAM developing Geoff's observation.
> >
> >
> >
> > I'm late in on this thread, so there may be a similar
>comment further up
> > my
> > in-box from somebody else.
> >
> > Geoff's observation is pretty fundamental:
> >
> > > My expectation is that the demarcation device will
>probably end
> > > up with an IP address in order to support:
> > > SNMP for OA&M
> > > Firewall services for the subscriber
> > >
> > > (That issue is, of course, beyond our scope)
> >
> > The logical conclusion of this observation is that EFM
>should make the
> > OAM
> > at layer two as simplistic as possible fulfilling only
>the basic
> > requirements i.e. limited number of managed objects
>and limited echo (L2
> > ping) test. Vendors can then leverage ietf standards
>(note: the users
> > tends
> > to like these) to implement ietf style 'standard'
>management functions.
> > Isn't that what we all have in mind anyway :-).
> >
> > The open question then is will the service provider
>market accept
> > in-band
> > management i.e. management IP frames mixed with user
>traffic, or is
> > there a
> > real requirement for a side-band channel. If EFM does
>need to include a
> > side
> > band channel then all that it needs to be is a
>communications channel
> > (bit
> > stream), probably squeezed in the preamble or the IPG
>(we can debate
> > that
> > choice for a while). Vendors can then implement either
>a standards based
> > method of comms over that channel or do there own
>thing. Personally I
> > would
> > expect vendors to choose something like IP over PPP
>for this.
> >
> > I can wrap this all up in a presentation for the next
>meeting if
> > required.
> >
> > (Just seen Geoff's comment on this in response to
>Roy's thread; as a
> > vendor
> > we will probably want to support both in-band and
>side-band,
> > standardised or
> > not, but we would prefer a standard for side band as
>part of EFM).
> >
> > Bob Barrett
> >
> > > -----Original Message-----
> > > From: owner-stds-802-3-efm@majordomo.ieee.org
> > > [mailto:owner-stds-802-3-efm@majordomo.ieee.org]On
><mailto:owner-stds-802-3-efm@majordomo.ieee.org%5DOn> Behalf Of Geoff
> > > Thompson
> > > Sent: 04 September 2001 23:03
> > > To: fkittred@xxxxxxx
> > > Cc: stds-802-3-efm@ieee.org
> > > Subject: Re: [EFM] OAM loop back / echo server
>function
> > >
> > >
> > >
> > > Fletcher-
> > >
> > > I don't think this is a stupid question.
> > > I don't think we need an IP level PING
> > > A L2 ping would do, perhaps even better, the demarc
>would look for
> > PING
> > > type and then just swap SA & DA.
> > > My expectation is that the demarcation device will
>need a MAC address
> > > My expectation is that the demarcation device will
>probably end
> > > up with an
> > > IP address in order to support:
> > > SNMP for OA&M
> > > Firewall services for the subscriber
> > >
> > > (That issue is, of course, beyond our scope)
> > >
> > > Geoff
> > >
> > > At 03:47 PM 9/4/01 -0400, Fletcher E Kittredge
>wrote:
> > > >On Fri, 31 Aug 2001 14:11:54 -0700 "Geoff
>Thompson" wrote:
> > > > > As I have said before, I do believe that we will
>need a
> > > demarcation device
> > > > > that has the capability to host OA&M functions.
> > > > > We have talked about "loop back" from this point
>in the network.
> > > > > Let us forevermore make that "PING"
> > > >
> > > >Geoff;
> > > >
> > > > Apologies if this is a stupid question,
>but does PING in
> > this
> > > >context mean the utility that sends an IP ICMP ECHO
>REQUEST packet
> > and
> > > >listens for an ECHO REPLY packet? If so, am I
>correct in thinking
> > this
> > > >means the demarcation device would require an IP
>address?
> > > >
> > > >thanks!
> > > >fletcher
> > >
> >