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Re: Lambda LSP Forwarding Adjacency Doubt
Manoj,
The transport plane is a multi layer network as described in G.805 and its
technology specific recommendations G.803, G.872 and I.326. Each layer network
operates independent from each other layer network. Each layer network uses the
transport service provided by its server layer networks, and represents this
transport service as (G.805) links within its own layer network.
In your example with nodes A, B, C and D, nodes A and D could operate on the
ODUk layer network (i.e. having an ODUk fabric) and nodes B and C would operate
on the OCh layer network (i.e. having an OCh fabric). Nodes A and D may have
also OCh fabrics, but this is not necessary; OCh termination points would
already be sufficient.
Let me give a 3 node example (4 nodes don't fit the page width in this email) in
which a STM-N signal is to be transported through A, B and C. At C the STM-N
signal leaves the network within an OTM-0.m signal.
node A node B node C
|<----------->|<------------------------------>|<------------------------->|
STM-N ----
|
------
|ODUk|
|port|
------
|
-------------- --------------------
| ODUk | | ODUk |
| Fabric | | Fabric |
-------------- --------------------
||...|....||| |||...|....||...|...
------ ------ ------
|OTUk| |OTUk| |OTUk|
|OCh | |OCh | |Och |
|port| |port| |port|
------ ------ ------
| ||....|...| |
| ---------------------------- ------------- |
| | OCh | | OCh | |
| | Fabric | | Fabric | |
| ---------------------------- ------------- |
||||||||||| ||||||||||| ||||||||| ||||||||| |
----------- ----------- --------- --------- -------
| OTM-n | | OTM-n | | OTM-n | | OTM-n | |OTM-0|
| port | | port | | port | | port | |port |
----------- ----------- --------- --------- -------
| | | | |
| | | | |
------------------- ---------------------- ------
The above network can be represented by means of its ODUk and OCh layer networks
as follows:
node A node B node C
|<----------->|<------------------------------>|<------------------------->|
STM-N ----
|
------
|ODUk|
|port|
------
|
-------------- --------------------
| ODUk | | ODUk |
| Fabric | | Fabric |
-------------- --------------------
|||| ||||||||| |||||||||| ||||||
| | | | | | | |
-- | | ---------------------------------------- | | ------
| | ODUk Link | | ODUk Link
----- --------------------------------------------------------- -----------
As you can see at the ODUk layer network, nodes A and C are neighbors. The
intermediate node B is totally invisible. ODUk signalling takes place therefore
between nodes A and C. The ODUk Connection Controllers (CC) (refer to G.8080) in
nodes A and C are connected with each other via the signalling communication
network.
| | |
------ ------ ------
|OTUk| |OTUk| |OTUk|
|OCh | |OCh | |Och |
|port| |port| |port|
------ ------ ------
| ||....|...| |
| ---------------------------- ------------- |
| | OCh | | OCh | |
| | Fabric | | Fabric | |
| ---------------------------- ------------- |
||| ||||||| ||||||||| ||||||||| ||||||||| ||||||
| | | | | | | | | | | |
-- | | --------- | | -------------- | | ---
| | OCh Link | | OCh Link | |
----- ----------------------- ------------------------------ --------
As you can see at the OCh layer network, nodes A and B and nodes B and C are
neighbors. OCh signalling takes place therefore between nodes A, B and C. The
OCh CCs in nodes A, B and C are connected with each other for this purpose via
the signalling communication network.
In the above 3-node example network, you will be able to setup ODUk connections
when the ODUk link is setup first. The ODUk link is created as part of network
planning and/or (distributed) network engineering. The ODUk link will exist when
one or more OCh trails are setup in the OCh layer network.
So when you want to setup an ODUk [i.e. a TDM LSP] connection you can ignore the
Lambda level.
Same principles apply of course to the SDH/SONET layer networks... i.e. you will
have a LOVC/VT layer with LOVC/VT links and a HOVC/STS layer with HOVC/STS
links.
This multi-layer principle doesn't require to stack labels.
Regards,
Maarten
manoj juneja wrote:
>
> Hi All,
> If there are 4 nodes say A, B, C and D. There is a Lambda FA
> established from A to D and if a new TDM LSP request comes to node A
> which is to be tunneled through the already established lambda FA-LSP
> then the node A sends the Path/label request message directly to node
> D. What label the node D will send back to node A in the RESV/label
> mapping message since the FA-LSP is just one label (lambda) ? Does it
> mean that all the LSPs which are tunneled through the lambda FA-LSP
> will be allocated the same label by node D to node A ?
>
> Please help.
>
> Regards,
> manoj.
>
> _________________________________________________________________
> Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp
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