Subject: Optical Interface MIB [draft 05] - proposal to model band amps.

From: "Rishi Grover" <[email-masked]>
Date: Tue, 25 Jun 2002 10:22:02 -0700

Hi,

Following some email discussions with Kam Lam and Mike Heard regarding the subject of modeling band-amplifiers in the Optical Interface MIB, I am putting forth a proposal for further comment in this mailing list.

ISSUE: 
There is a need to model sub-band amplifiers in the OPT-IF-MIB. The sub-band modeling describes the C and L band wavelengths muxed and amplified seperately before finally being muxed and transported over an OTN.

REQUIREMENT:
There is one set of OMS overhead corresponding to the OTS. So we need to maintain a 1-1 relationship between OTSn and OMSn. 

PROPOSAL:
One possible approach which makes the most efficent use of what is already proposed in the OPT-IF-MIB (draft 5) and at the same time allows us to model the banded amplifiers is described below:

[NOTE: I have taken Figures 5 and 6 from draft-05 and modified them to allow representation of C and L band amps].

        OCh (1 thru 80)
         |
         |               OChGroup1  OMSn
         |                   |       |
         |                   |       |        OTSn
         |                   |       |         |
         V                   |       |   |\    |
 ___|\_________|\      |\    V   |\  V   | \   V
    |/       . | \_____| \_______| \_____|  \______
             . | /     | /      _| /     |  /
           ----|/      |/      | |/      | /
          C-Band MUX   Amp     | Mux  +--|/
                               |      |  
                               |      |
 ___|\_________|\      |\      |     OSC 
    |/       . | \_____| \_____|
             . | /     | /        OSC Add Filter
        ^  ----|/      |/   ^      
        | L-Band MUX   Amp  |
        |                   |
        |                   |
        |              OChGroup2
        |
   OCh (81 through 160)
 
          Figure 1 - Source Side Monitoring Points

       OCh (1 thru 80)
         |
         |               OChGroup1  OMSn
         |                   |       |
         |                   |       |        OTSn
         |                   |       |         |
         V                   |       |         |
                             V       V     /|  V
 __/|__________/|       /|        /|      / |
   \|      .  / |______/ |_______/ |____ /  |_____
           .  \ |      \ |     __\ |     \  |
 __/|__________\|       \|    |   \|     _\ |
   \|   C-Band Demux   Amp    |  Demux  |  \|
                              |         |
                              |         |
 __/|__________/|       /|    |     OSC Drop Filter
   \|      .  / |______/ |____|
           .  \ |      \ |      
 __/|__________\|       \|       
   \|   L-Band Demux   Amp   ^            
                             |
        ^                    |
        |                    |
        |                    |
        |                OChGroup2
        |
   OCh (81 through 160)

         Figure 2 - Sink Side Monitoring Points

  +-----+-----+-----+   +-------+-----+------+  ---
  |OCh1 | ... |OCh80|   | OCh81 | ... |OCh160|   | <-- och ifEntries
  +-----+-----+-----+   +-------+-----+------+  ---
  |    OChGroup1    |   |     OChGroup2      |   | <-- ochGroup ifEntries
  +-----------------+---+--------------------+  ---
  |                 OMSn                     |   |
  +------------------------------------------+   | <-- otn ifEntries
  |                 OTSn                     |   |
  +------------------------------------------+  ---
 
Figure 3 - OCh, OMS, OTS Layering for DWDM Transport using Sub-Bands

If an implementation does not wish to model the banded-amplifiers, the OChGroup layer will be absent and the layering degenerates to what is currently proposed in the OPT-IF-MIB.

By introducing this capability in the MIB, the following changes would be required to draft 05:

- Introduce a new ifType enumeration called "OpticalChannelGroup"
- Define additional group of tables to handle config and performance information for the OChGroup.
- Conformance statements

Any other suggestions that you may have regarding this are most welcome.

Rgds,
Rishi