FORE/IP over SPANS

Types of ATM connections

ATM supports two types of SPANS connections: SVCs (switched virtual circuits) and PVCs (Permanent Virtual Circuits).

Use of SVCs

The filer dynamically assigns SVCs when interoperating with ATM hosts and with switches that support the FORE IP/SPANS protocols.

Use of PVCs

You use ATM PVCs to interoperate with ATM hosts and with switches that do not support FORE IP/SPANS. For example, if you are not using a FORE systems switch, PVCs can connect FORE equipment at each end through non-FORE switches.

Note: Data ONTAP currently supports only FORE/IP 5.3. The following differences from previous versions are significant:

The name of a SPANS interface in Data ONTAP 5.3 is fan (where n is a number); in previous versions of data ONTAP it was an. This means that you must change the interface names in your /etc/rc and /etc/hosts files.
In Data ONTAP 5.3, you use the new command atmconfig to configure PVCs.

For further information about the differences between FORE/IP 5.3 and older versions, consult FORE documentation.

PVCs are static; for each destination, you must establish (attach the IP layer to) a PVC explicitly and delete (detach the IP layer from) the PVC explicitly.

For each destination that needs to establish a PVC with the filer, you must establish an outgoing and an incoming PVC in at least three places:

On the filer
On the destination ATM host
On all interconnecting ATM switches

SPANS interfaces

For each physical ATM interface, the filer creates a FORE/IP interface, called fa, at boot time. The fa interface supports FORE/IP on top of SPANS signaling. FORE/IP allows communication as follows:

Using AAL4 or AAL5 ATM adaptation layer types with no encapsulation
Using a broadcast ARP (Address Resolution Protocol) for SPANS address resolution
Using direct communication of all hosts on a physical ATM network without the use of IP routers

Note: NetApp doesn't support FORE/IP load balancing or failover options.

Establishing an outgoing FORE/IP PVC on the filer

To establish an outgoing FORE/IP PVC on the filer, use the following filer command:

atmarp -s hostname pvc iface vpi vci [aal [encap [addr]]]


Variable	Description
hostname	Name or IP address of the remote host.
iface	Name of the ATM interface This is usually fan, where n is a number.
vpi	VPI (virtual path identifier); this must be 0.
vci	VCI (virtual channel identifier); this number must have the following properties: It must not be in use on your filer. It must be less than 1,024. It must obey the limits of the destination host and interconnecting devices.
aal	ATM adaptation layer type. It must be 4 or 5, and should be the AAL type supported by the destination host, which is typically 5. The default is 5.
encap	Encapsulation type. Specify one of the following encapsulation types: null (no encapsulation; this is the default) llc_routed (IEEE LLC encapsulation for routed PDUs) llc_bridged_8023 (IEEE LLC encapsulation for Ethernet/802.3 bridged PDUs) It should also be the same as the encapsulation type used by the destination host. If the encapsulation type is llc_bridged_8023, you must include addr.
addr	Six-byte colon-separated destination MAC address.

Establishing an incoming FORE/IP PVC on the filer

To establish an incoming FORE/IP PVC on the filer, use the following command at the filer:

atmarp -l pvc iface vpi vci [aal [encap]]

Use the variables as described in the previous section.

Establishing a FORE/IP PVC on the remote ATM host

Set up a FORE/IP PVC on the remote ATM host according to the documentation for that host.

Establishing a FORE/IP PVC on interconnecting ATM switches

On the interconnecting ATM switches, assign virtual channels corresponding to the VPI and VCI entries made on the filer and the remote ATM host according to the documentation for those switches.

Displaying information about a FORE/IP PVC

To display information about all FORE/IP PVCs and other interfaces on a host, use the following command:

atmarp hostname

hostname is the name of a host.

To display information about all the current FORE/IP PVCs, use the following command:

atmarp -a

A display similar to the following appears:

atmarp -a

iface=a5 switch.port=f21a2420.56 vpi.vci=0.114 aal=5

    encapsulation=NULL

iface=a5 switch.port=f21a2420.25 vpi.vci=0.113 aal=5

    encapsulation=NULL

Deleting a FORE/IP PVC

You can delete outgoing and incoming FORE/IP PVCs.

Deleting an outgoing FORE/IP PVC

To delete an outgoing FORE/IP PVC entry, use the following command:

atmarp -d hostname

hostname is the name or IP address of the remote host.

Deleting an incoming FORE/IP PVC

To delete an incoming FORE/IP PVC for a remote host, use the following command:

atmarp -x iface vpi vci

iface is the name of the interface

vpi and vci have the values of the VPI and VCI of the FORE/IP PVC to be deleted for the specified interface.

Part No. 210-02334
File: atm8.htm
Last updated: 02/24/99 12:16:13