general_configuration

General configuration

We use several configuration files to configure the mini-Internet and define its topology at the different layers. The configuration files must be in the config directory. They are organized in the following way:

config/
├── aslevel_links.txt            [inter-AS links and policies] 
├── aslevel_links_students.txt   [inter-AS links for students] 
└── AS_config.txt                [per-AS topology & config]
    ├── l3_router.txt            [L3 internal topology]
    ├── l3_links.txt             [L3 internal topology]
    ├── l2_switches.txt           ^
    ├── l2_hosts.txt              |   [L2 topology]
    └── l2_links.txt              v   

You must keep the filenames written above, except for the layer-3 configuration files, for which you can use different filenames because they are referred in the AS_config.txt file.

AS_config.txt

ℹ️ We automatically generate this file using a script, which we will explain in a following section.

The AS_config.txt is the main configuration file. It lists all the ASes and IXPs in the mini-Internet as well as the configuration files to use for every AS. The following table shows an example of this configuration file.

C1      C2      C3              C4                              C5                              C6              C7              C8
--------------------------------------------------------------------------------------------------------------------------------------------
1	AS	Config  	l3_routers_krill.txt	        l3_links_krill.txt	        empty.txt	empty.txt	empty.txt
2	AS	Config  	l3_routers_tier1_and_stub.txt	l3_links_tier1_and_stub.txt	empty.txt	empty.txt	empty.txt
3	AS	NoConfig	l3_routers.txt	                l3_links.txt             	l2_switches.txt	l2_hosts.txt	l2_links.txt
4	AS	NoConfig	l3_routers.txt	                l3_links.txt             	l2_switches.txt	l2_hosts.txt	l2_links.txt
5	AS	Config  	l3_routers_tier1_and_stub.txt	l3_links_tier1_and_stub.txt	empty.txt	empty.txt	empty.txt
6	AS	Config  	l3_routers_tier1_and_stub.txt	l3_links_tier1_and_stub.txt	empty.txt	empty.txt	empty.txt
11	AS	Config  	l3_routers_tier1_and_stub.txt	l3_links_tier1_and_stub.txt	empty.txt	empty.txt	empty.txt
12	AS	Config  	l3_routers_tier1_and_stub.txt	l3_links_tier1_and_stub.txt	empty.txt	empty.txt	empty.txt
13	AS	NoConfig	l3_routers.txt	                l3_links.txt             	l2_switches.txt	l2_hosts.txt	l2_links.txt
14	AS	NoConfig	l3_routers.txt	                l3_links.txt             	l2_switches.txt	l2_hosts.txt	l2_links.txt
15	AS	Config  	l3_routers_tier1_and_stub.txt	l3_links_tier1_and_stub.txt	empty.txt	empty.txt	empty.txt
16	AS	Config  	l3_routers_tier1_and_stub.txt	l3_links_tier1_and_stub.txt	empty.txt	empty.txt	empty.txt
80	IXP	Config  	N/A	                        N/A	                        N/A	        N/A	         N/A
81	IXP	Config  	N/A	                        N/A	                        N/A	        N/A	         N/A
82	IXP	Config  	N/A	                        N/A	                        N/A	        N/A	         N/A

Below you find the description for each column:

• C1: AS number.
• C2: Type of the network (either AS or IXP).
• C3: Config means the AS will be automatically configured (VLANs, OSPF, BGP, ...) whereas NoConfig means the AS is started without configuration (i.e., important for student ASes). Note: an IXP must be configured by default.
• C4: Name of the configuration file that lists the layer 3 routers within the AS and their parameters.
• C5: Name of the configuration file that describes the layer 3 internal topology.
• C6: Name of the configuration file that lists the layer 2 switches and their parameters.
• C7: Name of the configuration file that lists the hosts within the layer 2 network with their parameters.
• C8: Name of the configuration file that describes the layer 2 topology

In this example, the platform will build a mini-Internet comprising 12 ASes and 3 IXPs. Every AS comes preconfigured but AS 13 and 14.

ℹ️ At ETH Zürich, we use different topologies for the Tier1/Stub ASes (which are operated by the TA team) and the transit ASes (which are operated by the students) to limit the amount of resources used on our server. This is why we use different configuration files for these two types of ASes. By default, we also set krill (the Certificate Authority used for RPKI) in AS1.

⚠️ You can only configure the layer-2 networks in the configuration files l2_switches.txt, l2_hosts.txt and l2_links.txt (and only in those files). On the contrary, for the layer 3 networks, you can use different configuration files to define different layer-3 networks (like we do above).