The MPLS-OPS Archive

[<Nihal.Samaraweera@vf.vodafone.co.uk>]

(1) Yes a hybrid approach, but you could implement both techniques
independently.  An online process could be implemented to handle short-term
(minuets, hours) optimisation requirements, while off line method will
periodically (weeks, months interval) plan and optimise network.

(2) An online method uses constrained based routing to compute paths (one
example toward (but not exactly) this approach is Cisco Autobandwidth
allocator).  An offline tool may use a hybrid of an inventory based method
(e.g., keeping a spread sheet of bandwidth values (as well as the current
use) of all links in the network) and a constrained based routing method
(e.g., to compute exact optimum paths using loose routes derived from the
inventory based method).

Pl. correct me if I am wrong,

Nihal

-----Original Message-----
From: Antoine Bagula [mailto:bagula@cs.sun.ac.za]
Sent: 22 October 2001 11:26
To: Nihal.Samaraweera@vf.vodafone.co.uk
Cc: mpls-ops@mplsrc.com
Subject: RE: Off-line Versus ON-line routing



> Please correct me if I am wrong.
> 
> An offline or online routing is a way of optimising the network 
> resource, by periodically measuring and monitoring the status of
> the network.  An online process learns the status of the network
> using the additional information provided by the routing protocol.  
> 
> The route (e.g., LSP path) computation based on online method will 
> not use a deterministic approach, and the path establishment 
> depends only on the current state of the network. 
> 
> This lack of pre planing capability could be overcome using an 
> offline process. An offline optimisation process requires a set 
> of monitoring tools (to learn the status of the network), and a 
> set of network configuration management tools to compute and 
> configure an optimum set of routs (e.g. LSP paths).

1) By lack of preplanning capability which is overcome using an offline
process, Do you mean an hybrid approach combining on-line and off-line
routing? If so, how is such routing model implemented? 

2) do you (or someone else) know the difference between these two
approaches besides the performance  parameter.

Thanks in advance

Antoine B.

> 
> Nihal Samaraweera
> 
> 
> -----Original Message-----
> From: Antoine Bagula [mailto:bagula@cs.sun.ac.za]
> Sent: 22 October 2001 10:39
> To: mpls-ops@mplsrc.com
> Subject: Off-line Versus ON-line routing
> 
> 
> Dear All,
> 
> I would like to know what is the major difference between off-line and
> on-line routing as well as the relative gains and disadvantages of these
> two approaches. 
> 
> Antoine
> 
> 
> 
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