layer2_configuration

Layer-2 configuration

You can define one or more layer-2 networks inside every AS. You can do this through three configuration files that describe these layer-2 networks. These configuration files are applied on one or more ASes, according to the AS_config.txt file. In the following, we explain each configuration file and give an example.

l2_switches.txt

This file lists the switches in the layer-2 networks included in an AS. The following table shows an example of this configuration file.

C1     C2     C3           C4          C5
------------------------------------------
DCN    S1    ZURI   11:11:11:11:11:11   1
DCN    S2    BASE   22:22:22:22:22:22   2
DCN    S3    N/A    33:33:33:33:33:33   3
DCS    S4    GENE   44:44:44:44:44:44   4

Below is the description of each column.

C1: Name of the layer-2 networks. Here DCN (resp. DCS) means Data Center North (resp. South). 
C2: Name of all the layer-2 switches.
C3: Router to which every layer-2 switch is connected to (or N/A if the switch is not connected to a router).
C4: The MAC address to use on every the switch and that will serve as an 'ID'.
C5: The bridge ID to use for every switch in the spanning tree computation.

Note that a router can only be connected to one L2 network, but a layer 2 network can be connected to one or more routers.

ℹ️ When a switch is connected to a router, it must also be indicated in the third column of the l3_router.txt configuration file, which list the L3 routers. In the l3_router.txt configuration file, the name of the L2 network must always be preceded by L2-.

l2_hosts.txt

This file lists the hosts that are in the layer 2 network along with their parameters. The following table shows an example of this configuration file.

C1                   C2         C3    C4     C5      C6     C7
---------------------------------------------------------------
FIFA_1   miniinterneteth/d_host DCN   S1    10000   1000    10
UEFA_1   miniinterneteth/d_host DCN   S1    10000   1000    20
vpn_1    miniinterneteth/d_host DCN   S1    10000   1000    30
FIFA_2   miniinterneteth/d_host DCN   S2    10000   1000    10
UEFA_2   miniinterneteth/d_host DCN   S2    10000   1000    20
vpn_2    miniinterneteth/d_host DCN   S2    10000   1000    30
FIFA_3   miniinterneteth/d_host	DCN   S3    10000   1000    10
UEFA_3   miniinterneteth/d_host DCN   S3    10000   1000    20
vpn_3    miniinterneteth/d_host DCN   S3    10000   1000    30
FIFA_4   miniinterneteth/d_host DCS   S4    10000   1000    10
UEFA_4   miniinterneteth/d_host DCS   S4    10000   1000    20

Below is the description of each column.

C1: Name of the host.
C2: Docker image to use for this host.
C3: The name of the Data Center into which this host is located.
C4: The name of the switch to which to host is connected.
C5: The throughput of the link between the host and the switch.
C6: The delay of the link between the host and the switch.
C7: The VLANs to which the host belong to.

ℹ️ Observe that a host can be a VPN server, in which case its name must start with vpn_. In the example above, there are three VPNs (vpn_1, vpn_2 and vpn_3), all in DCN.

l2_hosts.txt

l2_topology.txt

layer2_links_config.txt: This file indicates how the l2 switches are interconnected. For instance by default ETHZ is connected to CERN and EPFL, etc. The last two columns indicate the throughput and the delay of the link, respectively. The first and third columns indicate the name of the L2 network in which the switches in the second and fourth columns are, respectively. The L2 names should be identical since it is not possible to connect two switches that are in two different L2 network.