Configuring ATM Networks
To establish a PVC, the following steps must be performed.
On the workstation, add an ATM ARP entry on each node specifying the PVC (vpi.vci pair) used to connect to each of the other hosts.
Create the PVC on the switch.
As an example, the following commands executed on the appropriate host will set up a PVC between nodes named node1 and node2, on interface 0, using a vpi of 0 and a vci of 70:
node1: atmarp -s node2 0.0.70
node2: atmarp -s node1 0.0.70
The commands above tell node1 to communicate with node2 over PVC 0.0.70 and for node2 to communicate with node1 over PVC 0.0.70. The atmarp command links the IP address of the target host to the PVC. You could choose a different PVC for each connection, but it is simpler to think in terms of one PVC connecting two machines.
The vpi.vci pair must not be in use on the host. Also, any ATM ARP cache entries must be deleted for the target host before creating the PVC. (These cache entries are created when SVCs are opened to the destination host.) To delete an ARP cache entry on node1 for node2, you would use this command:
node1: atmarp -d node2
Next, the switch must be configured to complete the PVC between the hosts. It is helpful to understand the port naming convention used by the Fore switch. The port names consist of three identifiers:
Board: the number of the switch board (same as the SCP number); each SCP controls one switch board.
Network Module: the slot (A, B, C, or D) in the switch board containing the port.
Port: the physical port number on the network module.
You must now create the virtual channels on the ATM switch. In our example, you would enter these commands on SCP 1:
localhost::> conf vcc localhost::configuration vcc> new 1a1 0 70 1a2 0 70 localhost::configuration vcc> new 1a2 0 70 1a1 0 70
1a1 is the switch port for node1 and 1a2 is the switch port for node2.
The switch completes the PVC based on the input port to output port virtual channel connection (VCC) mapping. Note that the PVC vpi.vci (0.70) matches the vpi.vci given to the atmarp commands on the hosts.
The above commands will connect two ports on the same ATM switch board. The Fore ASX-1000 switch has up to four switch boards. If you are connecting machines on different switch boards, the procedure is more complicated, as you must connect each port to the switch fabric and connect the fabric to each port. Thus, if you wish to connect a machine on port 1a1 to a machine on port 3a1, the following commands are required:
On SCP 1:
localhost::> conf vcc localhost::configuration vcc> new 1a1 0 70 1e3 0 70 localhost::configuration vcc> new 1e3 0 70 1a1 0 70
On SCP 3:
localhost::> conf vcc localhost::>configuration vcc> new 3a1 0 70 3e1 0 70 localhost::>configuration vcc> new 3e1 0 70 3a1 0 70On the Fore switch, the fabric connections are slot e. Therefore, port 1e3 refers to a connection from switch board 1 to switch board 3. Likewise, 3e1 refers to a connection from switch board 3 to switch board 1. Fore refers to these ports as “intra-fabric” ports.
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