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Sun Enterprise Server Alternate Pathing 2.0.1 User's Guide

Working With Network Pathgroups

To Create a Network Pathgroup
Note -

This procedure should not be used for the primary network. To alternately path the primary network, see "Alternately Pathing the Primary Network Interface".

  1. Use apnet(1M) with the -c option:


    # apnet -c -p le0 -a le2
# apconfig -N -u

metanetwork:    mle0  U
physical devices:
                le2 
                le0  P A

    This apnet(1M) command creates the network pathgroup as well as the metanetwork interface name mle0 for the two physical devices le0 and le2. The metanetwork interface name is derived from the primary controller name (specified by -p).

    The apconfig(1M) command lists the uncommitted network entries in the database. -N specifies that network database entries should be listed. -u specifies that uncommitted entries should be listed.

  2. If you are satisfied with the network pathgroup, commit the entry: 


    # apdb -C
# apconfig -N
 
metanetwork:    mle0 
physical devices:
                le2 
                le0  P A

    apdb -C commits the database entries. apconfig -N lists the committed network entries in the database. The listing appears exactly as it did before, except that the U no longer appears after mle0.

  3. Remove all direct usage of both members of the pathgroup (see ifconfig(1M)).

    1. You may have to unplumb the physical interface, for example:


      # ifconfig le0 down; ifconfig le0 unplumb

      If the interface you will be configuring down is the main network interface, or if it is the interface that you will be using as you use commands to configure the metanetwork, follow one of the procedures in "Alternately Pathing the Primary Network Interface".

      Usually network interfaces are configured during system boot via the file /etc/hostname.xxx, where xxx is the interface name (such as le0). This file contains the IP address or the hostname associated with the interface. You should remove or rename the /etc/hostname.xxx for all interfaces that have been made AP alternates, since direct usage of the alternate must not occur.

    2. Create an /etc/hostname.mxxx file (such as /etc/hostname.mle0) for any metanetworks that you want to configure at system reboot.

      This file should contain the metanetwork's IP address or the hostname for the interface. You can simply rename /etc/hostname.le0 to /etc/hostname.mle0.

      The normal operating state of a network interface is plumbed up when in use, and unplumbed when not in use. When you automatically configure network interfaces by using /etc/hostname.*, the interfaces are left in one of these states. It is possible to leave a network interface in a transitory state of plumbed when you manually configure your network interface. As this is not a normal operational mode it is unlikely that network interfaces will be left in this state. Generally, you should not leave metanetworks in this state during AP network configuration. A network metadevice may be deleted only if it and all other network metadevices of that device type are either in the unplumbed state or the plumbed up state. Otherwise, AP ignores the delete request, and depending on your configuration, may display warning messages of the following form:


      WARNING:mnf_setphyspath: APUNSET busy
WARNING:ap_db_commit: mnf3 not deleted, metadevice returned error 16

      Note -

      If you are using SunFDDI, you must specify a unique Media Access Control IDentifiers (MACIDs) for the metanetwork. The MACID is set by using the ether parameter to the ifconfig(1M) command. You might first examine the MACID for each of the alternates. You can do this by bringing up each alternate and examining the ether field. Then, fabricate a MACID that does not match any of the alternates. The allocation of MACIDs is described in RFC1340, "Assigned Numbers", July 1992. When generating a MACID for your AP network interface, the new 48 bit hardware address should be acquired from the IEEE Standards Office. However, it is possible to "create" a number by transposing digits on an existing MACID of one of the metainterface alternate elements. After creating a number, it is important to verify that there is no other hardware on the same subnet which is a legitimate user of the created address.

      This metanetwork MACID will be used to configure the active physical interface of the metanetwork. The use of this MACID is necessary to prevent duplication of MACIDs on the network when combining AP switching of interfaces and DR board insertion activities. The metanetwork defaults to the MACID of the active alternate on boot. To ensure that the MACID is set properly at boot time, place ifconfig(1M) commands in the /etc/rcs.d/S30rootusr.sh start-up script.

  4. Bring up the metanetwork in the usual manner, but use the metanetwork name instead of the physical network name.

    You can do this by either rebooting the machine or manually configuring the network as in the following example: 


    # ifconfig mle0 plumb
# ifconfig mle0 inet 136.162.65.30 up netmask + broadcast +
Setting netmask of mle0 to 255.255.255.0
# ifconfig -a
lo0: flags=849<UP,LOOPBACK,RUNNING,MULTICAST> mtu 8232
    inet 127.0.0.1 netmask ff000000 
mle0: flags=843<UP,BROADCAST,RUNNING,MULTICAST> mtu 4352
    inet 136.162.65.30 netmask ffffff00 broadcast 136.162.65.255
    ether 0:0:be:0:8:c5

    At this point, the device node, such as /dev/mle0, can be used to access the network from Solaris commands such as snoop(1M).

To Switch an Ethernet or SunFDDI Pathgroup
Note -

You can switch a network pathgroup even while the network sustains traffic.

  1. Use the apconfig(1M) command: 


    # apconfig -P mle0 -a le2
# apconfig -N
 
metanetwork:    mle0
physical devices:
                le2  A
                le0  P

    The -P option specifies the pathgroup and -a specifies the alternate that you want to become active. The listing above shows that the active alternate has been switched to le2, as indicated by the A following le2.

    You do not have to commit a switch operation.

    Caution - Caution -

    When you switch paths, AP does not check to verify that data can be transmitted over the path to which you are switching (although it does determine whether or not that path is detached or offline). You may want to verify the status of the path before switching to it by performing an I/O operation such as snoop(1M). AP does not produce any error or warning messages if you switch to a path that is not functioning properly.

To Delete a Network Pathgroup

  1. Remove all usage of the corresponding metanetwork, and use apnet -d: 


    # ifconfig mle0 down unplumb
# apnet -d mle0
# apconfig -N
 
metanetwork:    mle0  D
physical devices:
                le2  A
                le0  P

    In the listing produced by apconfig -N, a D follows mle0, indicating that the pathgroup is marked as deleted.

  2. Commit the entries in the database using apdb -C: 


    # apdb -C
# apconfig -N
#

    The apconfig -N command produces no listing, indicating that the network pathgroup (the only one that existed previously in this example) has been deleted.

    You can undo a deletion if the deletion is uncommitted. To undo a deletion, run apnet -z, specifying the same metanetwork interface that you previously deleted.

    When an apnet -m -r or apnet -m -a command is used, AP marks the current pathgroup configuration as deleted and creates a new uncommitted pathgroup definition. After the database change is committed by using apdb -C, the new definition replaces the old.