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Thomas Holterbach edited this page Apr 4, 2022 · 18 revisions

AS-level configuration

The last configuration files describe the AS-level topology and give additional parameters such as which IP prefix to use for a given inter-AS link.

The file aslevel_links.txt is used to build the mini-Internet whereas the file aslevel_links_students.txt is a file that must be shared with the students and that contains useful information for them, such as with which ASes their AS is directly connected to and which IP prefix to use for an inter-AS link.

Automatic generation of the configuration files

These configuration files can be quite long (one line for every inter-AS link) and thus hard to write manually. We thus provide a script called generate_configurations.py that automatically generates these two configuration files. Once generated by our script, just copy the resulting config files in the config directory.

ℹ️ This script also generates the AS_config.txt file.

The pattern of the AS-level topology is however hard coded in this script (different regions interconnected with IXPs, etc). We provide different sizes of the topology, thus you can easily generate a 12-ASes topology or 70-ASes topology (use the NB_ASES variable in the source code to change the size).

If you want to use your own AS-level topology that exhibits a different pattern than the one we use, you will have to build those configurations files yourself (either manually or using a script that you must write).

aslevel_links.txt

We now show and explain the content of this configuration file for a 12-ASes topology and when generated using our generate_configuration.py script. Each line corresponds to an inter-AS link.

C1   C2       C3      C4     C5       C6          C7     C8         C9
---------------------------------------------------------------------------------
1	ZURI	Peer	  12	ZURI	Peer	    100000	1000	179.0.1.0/24
1	ZURI	Customer  3	    BASE	Provider	100000	1000	179.0.2.0/24
1	ZURI	Customer  4	    MUNI	Provider	100000	1000	179.0.3.0/24
1	ZURI	Peer	  80	None	Peer	    100000	1000	1,2,11,12
1	BASE	Peer	  81	None	Peer	    100000	1000	11,12,13,14,15,16
1	ZURI	Peer	  2	    ZURI	Peer	    100000	1000	179.0.4.0/24
2	ZURI	Customer  4	    BASE	Provider	100000	1000	179.0.5.0/24
2	ZURI	Customer  3	    MUNI	Provider	100000	1000	179.0.6.0/24
2	ZURI	Peer	  80	None	Peer	    100000	1000	1,2,11,12
2	BASE	Peer	  82	None	Peer	    100000	1000	11,12,13,14,15,16
11	ZURI	Peer 	  2	    ZURI	Peer	    100000	1000	179.0.7.0/24
11	ZURI	Customer  13	BASE	Provider	100000	1000	179.0.8.0/24
11	ZURI	Customer  14	MUNI	Provider	100000	1000	179.0.9.0/24
11	ZURI	Peer	  80	None	Peer	    100000	1000	1,2,11,12
11	BASE	Peer	  82	None	Peer	    100000	1000	1,2,3,4,5,6
11	ZURI	Peer	  12	ZURI	Peer	    100000	1000	179.0.10.0/24
12	ZURI	Customer  14	BASE	Provider	100000	1000	179.0.11.0/24
12	ZURI	Customer  13	MUNI	Provider	100000	1000	179.0.12.0/24
12	ZURI	Peer	  80	None	Peer	    100000	1000	1,2,11,12
12	BASE	Peer	  81	None	Peer	    100000	1000	1,2,3,4,5,6
3	LYON	Customer  5	    ZURI	Provider	100000	1000	179.0.13.0/24
3	MILA	Customer  6	    ZURI	Provider	100000	1000	179.0.14.0/24
3	LUGA	Peer	  4	    LUGA	Peer	    100000	1000	179.0.15.0/24
3	VIEN	Peer	  81	None	Peer	    100000	1000	11,12,13,14,15,16
4	LYON	Customer  6	    ZURI	Provider	100000	1000	179.0.16.0/24
4	MILA	Customer  5	    ZURI	Provider	100000	1000	179.0.17.0/24
4	VIEN	Peer	  82	None	Peer	    100000	1000	11,12,13,14,15,16
13	LYON	Customer  15	ZURI	Provider	100000	1000	179.0.18.0/24
13	MILA	Customer  16	ZURI	Provider	100000	1000	179.0.19.0/24
13	LUGA	Peer	  14	LUGA	Peer	    100000	1000	179.0.20.0/24
13	VIEN	Peer	  82	None	Peer	    100000	1000	1,2,3,4,5,6
14	LYON	Customer  16	ZURI	Provider	100000	1000	179.0.21.0/24
14	MILA	Customer  15	ZURI	Provider	100000	1000	179.0.22.0/24
14	VIEN	Peer	  81	None	Peer	    100000	1000	1,2,3,4,5,6
5	ZURI	Peer 	  6	    ZURI	Peer	    100000	1000	179.0.23.0/24
5	BASE	Peer	  81	None	Peer	    100000	1000	11,12,13,14,15,16
6	BASE	Peer	  82	None	Peer	    100000	1000	11,12,13,14,15,16
15	ZURI	Peer	  16	ZURI	Peer	    100000	1000	179.0.24.0/24
15	BASE	Peer	  82	None	Peer	    100000	1000	1,2,3,4,5,6
16	BASE	Peer	  81	None	Peer	    100000	1000	1,2,3,4,5,6

Below is the description of each column.

C1: AS number of the AS on one end of the link.
C2: Router within the AS in C1 that is connected to the other AS.
C3: With which type of business relationship the AS in C1 is connected to the neighboring AS in C4. For instance, the second line indicates that AS1 is a provider of AS4, and AS4 a customer of AS1.
C4: Same as C1 but for the other end of the link.
C5: Same as C2 but for the other end of the link.
C6: Same as C3 but for the other end of the link.
C7: The throughput of the link.
C8: The delay of the link.
C9: Two possible cases:
    - When its an AS-to-AS link: IP prefix to use for the eBGP sessions.
    - When its an AS-to-IXP link: which participants of the AS should peer with.

To illustrate, the second line indicates that ZURI in AS1 is connected to BASE in AS3, and AS1 is the provider of AS3.

To reduce the server load, an IXP AS contains only one router. Therefore, C5 is None when there is an IXP. C9 is used to autoconfigure the different networks and have network-wide connectivity when using the Config in the AS_config.txt configuration file.

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