RE: Suppression of Downstream Alarms...

[Jonathan Lang <[e-mail]>]

Carmine,
  Please see inline.

Thanks,
Jonathan

> -----Original Message-----
> From: Carmine Daloia [mailto:[e-mail]]
> Sent: Monday, November 19, 2001 6:44 AM
> To: [e-mail]
> Cc: [e-mail]; [e-mail]
> Subject: LMP: Suppression of Downstream Alarms...
> 
> 
> Hi all,
> 
> As I read through Section 6 "Fault Management", one issue that it seems 
> to be addressing is "Suppression of Downstream Alarms".
> 
> In section 6.2, it states that "If data links fail between two PXCs, the 
> power monitoring system in all of the downstream nodes may detect LOL 
> and indicate a failure. To avoid multiple alarms stemming from the same 
> failure, LMP provides a failure notification through the ChannelStatus 
> message...".
> 
> I agree that the suppression of downstream alarms is an important issue.
great!

> 
> If we look at standard networks (both SONET/SDH and OTN), this 
> capability is already provided by the overhead in SDH/SONET and G.709 
> OTN. G.709 OTN handles suppression of alarms in both all-optical 
> networks as well as opaque networks. I don't think we need to burden the 
> control plane with such functions when the transport plane handles this 
> in standard networks. In fact the transport plane handles suppression of 
> alarms on all equipment in the network (not just cross-connects).
> 
> If we look at a pre-OTN ("non-standard") scenario consisting of 
> Cross-connects, Optical Line Systems, and Optical Amplifiers supporting 
> a DWDM networked solution, we can analyze two scenarios. One scenario is 
> an opaque network (e.g., the OLS supports 3R). In this scenario, the 
> downstream Cross-connects would not detect LOL upon faults occurring 
> upstream. The 3R points on the OLS Line Systems would insert some type 
> of signal downstream. Therefore the mechanism described in Section 6.2 
> does not apply. Another scenario is an all-optical pre-OTN network. Note 
> that other equipment besides Cross-connects (e.g., Optical Amplifiers) 
> in an all-optical network may alarm due to upstream faults. These alarms 
> also need to be suppressed. LMP seems to only address the suppression of 
> downstream alarms on cross-connects without taking into consideration 
> the network that sits between the cross-connects. Is LMP also expected 
> to have to be processed on Optical Amplifiers? This seems to be 
> undesirable, especially given all the various applications that seem to 
> be included into the LMP protocol that would not have anything to do 
> with Optical Amplifieris.
For interaction between cross-connects and Line Systems, please see OLI
Requirements document
(http://search.ietf.org/internet-drafts/draft-many-oli-reqts-00.txt) and
corresponding LMP-WDM protocol document (new version to be uploaded
tomorrow, but old version can be found at
http://search.ietf.org/internet-drafts/draft-fredette-lmp-wdm-02.txt).

> 
> Any other views?
> 
> Carmine
>