RE: [T1X1.5] Re: Suppression of Downstream Alarms...

["George Young" <[e-mail]>]

A couple of my mail message on this subject were bounced whilst I was 
in the process of changing email address to correspond with my company's
new name.

2 Attachments:

 <<RE: [T1X1.5] Re: Suppression of Downstream Alarms...>>  <<RE:
[T1X1.5] Re: Suppression of Downstream Alarms...>> 

--- Begin Message ---

Hello Carmine,
 
For span protection, LMP can stand on its own, localizing the fault,
making sure
that both ends of the fault span know about the failure.
 
In a transparent network (which is where my company is focused), the
node at the receive
end of a faulty link, and any nodes downstream (in the data flow
direction) become aware 
of the fault, so one end of the path knows almost immediately.
 
For path protection, there would still be a need for signalling to the
other end. The benefit 
of using LMP to localize the fault, is that only one node need initiate
the signalling to the 
head and the tail of the connection to toggle to the backup path.
 
Regards,
George R. Young
Meriton Networks Inc. 
329 March Rd., Kanata, ON, Canada, K2K 2E1 
phone: [phone] Ext 287 
fax: [phone] 

-----Original Message-----
From: Carmine Daloia [mailto:[e-mail]]
Sent: Wednesday, November 21, 2001 9:23 AM
To: George Young
Cc: [e-mail]
Subject: Re: [T1X1.5] Re: Suppression of Downstream Alarms...


Hi George,

Thanks for the pointer to your draft. I will definitely read over it.
Just looking at it quickly and understanding what is in LMP, it seems
that even under path protection/restoration, there is an intermediate
node that detects a failure (and localizes the failure to ensure that
the failure occured on that particular link) and then signals over the
control plane to the head-end and tail-end nodes of the
protection/restoration domain to initiate protection/restoration.

It seems to me that the tail-end and head-end nodes themselves would be
able to detect the defect in the transport/user plane since the defect
occured between the two ends and they can then coordinate switching for
protection/restoration without having to wait for any notification
message sent from an intermediate NE.  This should improve the
protection/restoration time since the head-end and tail-end won't need
to wait for intermediate nodes to localize a fault and then signal over
a control plane requesting a proteciton/restoration switch. Any
thoughts?

Thanks
Carmine

George Young wrote:


Hello Carmine,
 
Meriton Networks intends to use LMP as a fault localization mechanism in
a network of
our transparent optical switches, currently in the pre-production phase.
 
I've done some discrete event simulation work to characterize the
performance of an IP
network in support LMP management signals, and the resulting signalling
messages needed
to initiate protection/restoration, and based on the results, have not
seen any need to change 
our design direction.
 
I've also written and submitted an IETF draft 
http://search.ietf.org/internet-drafts/draft-young-opt-nni-prot-issues-0
0.txt 
dealing with the importance of control network performance, particularly
when extended across 
multiple networks, and would appreciate any comments you might have.
 
Regards,
George R. Young
Meriton Networks Inc.
329 March Rd., Kanata, ON, Canada, K2K 2E1
phone: [phone] Ext 287
fax: [phone]

-----Original Message-----
From: Carmine Daloia [ mailto:[e-mail]]
Sent: Wednesday, November 21, 2001 8:29 AM
To: Carmine Daloia
Cc: Jonathan Lang; [e-mail]; [e-mail]; [e-mail]
Subject: Re: [T1X1.5] Re: Suppression of Downstream Alarms...


Jonathan,

Forgot to mention, that the performance aspects of carrying OAM type
signals over an IP based control channel in LMP-WDM would have to be
analyzed. It is possible that the IP Control Channel will not provide
fast enough transfer to actually suppress downstream alarms, however
that needs to be analyzed as part of LMP-WDM.

Thanks
Carmine

Carmine Daloia wrote:


Jonathan,

The LMP-WDM document specifies the signaling between the Cross-connect
and OLS, assuming they are from different vendors. If they are from
different vendors, then a standard interface is needed to exchange some
information. One type of information that would need to be exchanged is
some OAM signals. Maarten described some of these signals in his VBI
document. However, I don't see why OAM signals would have to be
exchanged directly between the cross-connects themselves via LMP.

Let's look at the following network.

OXC1 --- OLSA --- OXC2 --- OLSB --- OXC3 --- OLSC --- OXC4

Note that the OLS consists of DWDM Mux/Dmux Terminals and Optical
Amplifiers.

Let's assume a failure on OLSA. OLSA via overhead within an OSC
suppresses alarms within OLSA. OAM messages (e.g., Optical Channel FDI)
could be carried over the LMP-WDM control channel to OXC2. OXC2 will
have to forward the FDI signals downstream over the LMP-WDM control
channel to OLSB. OLSB will then forward these FDI signals over its OSC
and then over the LMP-WDM control channel to OXC3..... etc...

Note that OXC2 does not need to directly forward these FDI signals to
OXC3. So it is possible, that in LMP-WDM, we may need to define messages
corresponding to FDI signals to suppress downstream alarms, however we
don't need to define such messages in LMP.

Thanks
Carmine

Jonathan Lang wrote:


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

 Cha
nn
elStatus 
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

 dow
ns
tream. 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

--- End Message ---

--- Begin Message ---

Hello Carmine,
 
Meriton Networks intends to use LMP as a fault localization mechanism in
a network of
our transparent optical switches, currently in the pre-production phase.
 
I've done some discrete event simulation work to characterize the
performance of an IP
network in support LMP management signals, and the resulting signalling
messages needed
to initiate protection/restoration, and based on the results, have not
seen any need to change 
our design direction.
 
I've also written and submitted an IETF draft 
http://search.ietf.org/internet-drafts/draft-young-opt-nni-prot-issues-0
0.txt
dealing with the importance of control network performance, particularly
when extended across 
multiple networks, and would appreciate any comments you might have.
 
Regards,
George R. Young
Meriton Networks Inc. 
329 March Rd., Kanata, ON, Canada, K2K 2E1 
phone: [phone] Ext 287 
fax: [phone] 

-----Original Message-----
From: Carmine Daloia [mailto:[e-mail]]
Sent: Wednesday, November 21, 2001 8:29 AM
To: Carmine Daloia
Cc: Jonathan Lang; [e-mail]; [e-mail]; [e-mail]
Subject: Re: [T1X1.5] Re: Suppression of Downstream Alarms...


Jonathan,

Forgot to mention, that the performance aspects of carrying OAM type
signals over an IP based control channel in LMP-WDM would have to be
analyzed. It is possible that the IP Control Channel will not provide
fast enough transfer to actually suppress downstream alarms, however
that needs to be analyzed as part of LMP-WDM.

Thanks
Carmine

Carmine Daloia wrote:


Jonathan,

The LMP-WDM document specifies the signaling between the Cross-connect
and OLS, assuming they are from different vendors. If they are from
different vendors, then a standard interface is needed to exchange some
information. One type of information that would need to be exchanged is
some OAM signals. Maarten described some of these signals in his VBI
document. However, I don't see why OAM signals would have to be
exchanged directly between the cross-connects themselves via LMP.

Let's look at the following network.

OXC1 --- OLSA --- OXC2 --- OLSB --- OXC3 --- OLSC --- OXC4

Note that the OLS consists of DWDM Mux/Dmux Terminals and Optical
Amplifiers.

Let's assume a failure on OLSA. OLSA via overhead within an OSC
suppresses alarms within OLSA. OAM messages (e.g., Optical Channel FDI)
could be carried over the LMP-WDM control channel to OXC2. OXC2 will
have to forward the FDI signals downstream over the LMP-WDM control
channel to OLSB. OLSB will then forward these FDI signals over its OSC
and then over the LMP-WDM control channel to OXC3..... etc...

Note that OXC2 does not need to directly forward these FDI signals to
OXC3. So it is possible, that in LMP-WDM, we may need to define messages
corresponding to FDI signals to suppress downstream alarms, however we
don't need to define such messages in LMP.

Thanks
Carmine

Jonathan Lang wrote:


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 Cha

nn
elStatus 
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 dow

ns
tream. 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

--- End Message ---