gt-itm模型生成拓扑结构

终于翻译成中文了,可自己都觉得这译得自己都不太懂.暂时先这样吧
从GT-ITM拓扑产生器产生图表
    下载 GT-ITM Topology Generator软件
    GT-ITM拓扑产生器可以创建一种平面随机的图表和两种层次型的图表,N-level和transit-stub.看看在这个叫Daniel Zappala的主页上的例子(实际上这个超链接已经没用).也看看在GT-ITM目录下的目录的一些文档.我个人觉得看readme之类的文档非常有用.
    例如:我们使用200个节点创建一个transit-stub图表.那么我们先创建一个说明书一样的文件,叫ts200,其代码如下    (?ts200?怎么没有后缀名呢?)
## Comments :
   ## <#method keyword> <#number of graphs> [<#initial seed>]
   ## <#stubs/xit> <#t-s edges> <#s-s edges>
   ## <#n> <#scale> <#edgemethod> <#alpha> [<#beta>] [<#gamma>]
   ## number of nodes = 1*8* (1 + 4*6) = 200
   ts 10 47
   4 0 0
          1 20 3 1.0
          8 20 3 0.8
          6 10 3 0.5
运行命令"itm ts200",10 transit-stub图表,每个图表有200个节点(?),初始种子为47个.
    "4 0 0"
每个transit节点有四个域连接;没有额外的transit-stub边缘和stub-stub边缘.               "1 20 3 1.0"
每个图表有一个transit域
    "8 20 3 0.8 "
每个transit域有平均8个transit节点,在一对节点节有一个边缘(?),这样的概率为0.8.
    "6 10 3 0.42 "
每个stub域有平均6个节点每一对节点有一个边缘(?),这样的概率为0.5

Conversion of GT-ITM output to ns-2 format(变换gt-itm为ns2格式)
配置好gt-itm后使用sgb2ns ts200-0.gb ts200.tcl 命令执行.



注:Transit-Stub模型将AS域划分为Transit类和Stub类.在该模型中,Transit节点彼此互联构成一个节点群,一个或多个Transit节点群构成拓扑图的核心,而Stub节点分布在Transit节点群四周与Transit节点相连.Transit -Stub是GT-ITM(georgia tech Internetwork topology models)软件包的一部分,有时GT-ITM也就是指Transit-Stub模型.

Georgia Tech Internetwork Topology Models
Generating graphs from GT-ITM topology generator.
Download the GT-ITM Topology Generator software.
The GT-ITM topology generator can be used to create flat random graphs and two types of hierarchical graphs, the N-level and transit-stub. Take a look at the examples in Daniel Zappala's homepage. Also look at the documents under docs subdirectory of GT-ITM's distribution.
For example, we need to create a transit-stub graph with 200 nodes. So we create a specification file, say ts200, that goes like this:
   ## Comments :
   ## <#method keyword> <#number of graphs> [<#initial seed>]
   ## <#stubs/xit> <#t-s edges> <#s-s edges>
   ## <#n> <#scale> <#edgemethod> <#alpha> [<#beta>] [<#gamma>]
   ## number of nodes = 1*8* (1 + 4*6) = 200
   ts 10 47
   4 0 0
   1 20 3 1.0
   8 20 3 0.8
   6 10 3 0.5
        
On running 'itm ts200', 10 transit-stub graphs with 200 nodes each will be created starting with initial seed 47. line 4 0 0 means each transit node will have 4 stub domains connected to it;there shall be no extra transit-stub edges and no extra stub-stub edges. Line 1 20 3 1.0 means there will 1 transit domain in each graph. Line 8 20 3 0.8 says each transit domain will have, on an average, 8 transit nodes with an edge between each pair of node with a probability of 0.8 and line 6 10 3 0.42 says every stub domain shall have, on an average, 6 nodes each with an edge between every pair with a probability of 0.5.
For a more complete description of the parameter specification file see models.ps file under docs subdirectory.
The graphs produced are named as ts200-[0 to 9].gb and are in Stanford Graph Base Output format. This needs to be converted to tcl format for ns-2 to interpret it correctly.
Conversion of GT-ITM output to ns-2 format
Download the sgb2ns conversion program. Follow instructions in the README file and create the sgb2ns executible. Note that sgb2ns should be expanded in the gt-itm directory, and its executibles will be placed in gt-itm/bin subdirectory. This distribution also contains ts2ns and sgb2hier as described below.
Modify sgb2ns's Makefile to make macro GT_ITM to point to the right path and correct Stanford Graphics Base library name installed in your system(e.g libgd.a, libgb4.a or libgb5.a etc). The library also comes as a part of gt-itm distribution. Under any circumstance it should reside under gt-itm/lib.
sgb2ns converts the sgb output to tcl output.
Usage : sgb2ns ts200-0.gb ts200.tcl