Network model input file (simple ASCII) for SNDlib




This page describes the ASCII file format for the network model file. See the format overview page for a description of the other input and output files.

Summary

The general properties of a particular network planning instance are described by a so-called network model, which comprises a specification of


Demand model

UNDIRECTED
Each demand is routed without direction between its end-nodes. In this case, the link model must be UNDIRECTED. This case corresponds to a triangular traffic matrix.
DIRECTED
Each demand is routed from source to target. In this case, every link model is admissible. The directed links can only be used in their direction. Accordingly, capacity is consumed in this direction. This case corresponds to an unsymmetric traffic matrix.



Link model

UNDIRECTED
Links are undirected, that is, the installed routing capacity can be used in both directions to route communication demands. The sum of the flows in both directions must not exceed the installed capacity.
BIDIRECTED
Links are bidirectional, that is, the installed routing capacity can be used in both directions to route communication demands. The maximum of the flows in both directions must not exceed the installed capacity. If the link model is bidirected, the demand model should be DIRECTED.
DIRECTED
Links are directed, that is, the installed routing capacity can be used in the direction from the source node to the target node. The flow in this direction must not exceed the installed capacity. If the link model is directed, the demand model should be DIRECTED as well.



Link capacity model

LINEAR_LINK_CAPACITIES
Any non-negative (fractional or integer) capacity can be installed on the links.
SINGLE_MODULAR_CAPACITIES
Only the module type with the smallest capacity can be installed, i.e. only its capacity variable can be nonnegative and integer. All others have to be 0.
MODULAR_LINK_CAPACITIES
All non-negative integer combinations of the base capacities specified for the link are admissible.
EXPLICIT_LINK_CAPACITIES
An explicit list of all admissible capacities on a link is provided. At most one of them may be installed, and only once.



Fixed charge model

YES
Take the fixed charge cost specification of the links into account.
NO
Ignore the fixed charge cost specification of the links (i.e., assume fixed charge cost 0 for all links).



Routing model

CONTINUOUS
Any fraction of a demand can be carried on any admissible path for the demand. A bifurcated routing is allowed.
INTEGER
Integer multiples of the routing unit of a demand can be routed on any admissible path for the demand. A bifurcated routing is allowed.
SINGLE_PATH
Each demand must be completely routed over a single admissible path.
OSPF_SINGLE_PATH
Planned for a later version.
OSPF_EQUAL_SPLIT_PATH
Planned for a later version.



Admissible path model

ALL_PATHS
For each demand, all paths satisfying the hop limits can be used. Any explicit list of admissible paths is ignored.
EXPLICIT_LIST
For each demand an explicit list of admissible paths must be specified. Only these paths are admissible (provided that they satisfy the given hop limits).



Hop limit model

INDIVIDUAL_HOP_LIMITS
Use only those admissible paths (either given by an explicit list or implicitly) which satisfy the hop limit specified for each demand.
IGNORE_HOP_LIMITS
Ignore the hop limit specification of the demands, i.e., routing paths are not length-restricted.



Node model

NO_NODE_HARDWARE
No hardware like multiplexers, cross-connects, line-cards, etc. is considered in the current version.
NODE_HARDWARE
Planned for Version 2.0 (multiplexers, cross-connects, line-cards, ports).



Objective model

MINIMIZE_TOTAL_COST
Minimize total network cost, which is the sum of link capacity cost, fixed-charge cost, routing cost, and (from Version 2.0 on) hardware cost.



Survivability model

NO_SURVIVABILITY
No survivability needs to be ensured in the routing.
ONE_PLUS_ONE_PROTECTION
The routing of every demand must satisfy the conditions of 1+1 dedicated path protection. That is, each demand must be routed on a single working path in the normal operating state, and a single link-disjoint backup path must be provided to protect the demand against single link failures.
SHARED_PATH_PROTECTION
For each demand, a working path routing for the non-failure state and an end-to-end backup path for each single link failure must be provided. In each failure state, all non-affected working paths must be maintained. The backup capacity is shared among the different demands as well as between the network states, i.e., the backup path may depend on the specific link failure. The capacity of failing working paths is released and can be reused in failure states.
UNRESTRICTED_FLOW_RECONFIGURATION
For each demand, independent routings must be provided for the non-failure state as well as for all single link failure states. The routings of a demand in the different states are not coupled in any way.


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