How to Configure and Troubleshoot an AIX ATM Switched Virtual Circuit

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Configuring switched virtual circuits

An ATM address is 20 bytes (40 hex digits) in length and listed in dotted decimal format. Following is an ATM address example:

	AC.3E.21.11.6F.3.AA.16.19.A0.3.D.12.33.D4.A2.CC.D.8.5

When configuring the system as an ARP server-client, it is necessary to know the ATM address of the ARP server. Usually you obtain this address from your network support or your ATM switch support administrator. It must be correct and entered correctly through SMIT as described subsequently. Otherwise, the system ATM client will not register with the ATM switch and ARP server.

   * INTERNET ADDRESS (dotted decimal)                  (1.1.1.1)
     Network MASK (hexadecimal or dotted decimal)       (255.255.255.0)
     Network Interface                                  (at0)
     Connection Type                                     svc_c
     ATM Server Address                   (20 byte ARPserver ATM address)
     Alternate Device                                   (atm0)
     Idle Timer                                         ()
   * ACTIVATE the Interface after Creating it?           yes

ATM ARP server configuration

   * INTERNET ADDRESS (dotted decimal)                  (1.1.1.1)
     Network MASK (hexadecimal or dotted decimal)       (255.255.255.0)
     Network Interface                                  (at0)
     Connection Type                                     svc_s
     ATM Server Address                                 ()
     Alternate Device                                   (atm0)
     Idle Timer                                         ()
   * ACTIVATE the Interface after Creating it?           yes

If you are configuring the system as an ARP server-client, set the Connection Type field to svc_c. If you are configuring the system as an ARP server, then set Connection Type to svc_s.

Multiple interfaces may be configured on one ATM adapter (that is, at0, at1, at2, and so on). Therefore, it is necessary to specify the interface designator (at0, at1, and so on) in the Network Interface field.

A unique network address must be assigned to each interface; otherwise, confusion in the routing table will exist. For example, you may not be able to ping or telnet out on one of the duplicated networks. AIX supports only network interfaces which have unique network addresses.

Due to the possibility of having multiple adapters in the system, the ATM physical device on which the atx interface is being created must be specified in the Alternate Device field.

 at0(2.2.2.160)  47.0.5.80.ff.e1.0.0.0.f2.15.16.45.8.0.5a.99.a.cc.0

 (2.2.2.125)  47.0.5.80.ff.e1.0.0.0.f2.15.16.45.8.0.5a.89.0.33.0

Troubleshooting SVCs

1. Check to make sure there is a proper connection to the ATM switch. This is usually indicated by a port light on the ATM switch. Look for wire fault errors in the error log by using the errpt |grep atm command to identify cable problems. If the SC connectors on your fiber cables are not keyed or connected with a plastic cover, try reversing the connectors on one end.

2. Ensure that the ARP server ATM address has been entered correctly for the ARP client. Executing lsattr -El atx will show the ATM address.

3. Many problems occur when the switch is incorrectly configured. If no one can ping on the switch and you have double-checked the configuration on AIX, please contact the switch administrator to verify the configuration.

4. Running atmstat -d atm0
   Assuming there is a good physical connection to the ATM switch, the following command sequence will tell you if the ATM adapter and device driver are working.
   1. Execute atmstat -d atm0 > /tmp/atmstat.out and then wait 10 seconds.

   2. Execute the command again, this time appending it. Use >>.

      atmstat -d atm0 >> /tmp/atmstat.out
      

   3. Edit the file and check the following parameters in the Receive Statistics column: Packets and Cells received. These two parameters should show an increase in the second atmstat, which means the adapter and device driver are working.

      No increase in either parameter means the adapter is not able to receive ATM cells or there may be a problem with the atmsvcd--the ATM call manager daemon.

      If either number is not increasing, check to see if the atmsvcd daemons are running with the following command:

      ps -ef |grep atm
      

      The output should read:

      root 2816    1   0 12:08:57      -  0:00 /usr/sbin/atmsvcd
      root 3844 2816   0 12:08:57      -  0:02 /usr/sbin/atmsvcd
      

      For a single ATM adapter, two atmsvcd processes should exist. If no process exists, restart the daemon /usr/sbin/atmsvcd. If only one process is running, execute kill -9 <child pid> (the child pid in the example is 3844) and then restart the daemons. The addition of the second or additional ATM adapter in the system only adds one atmsvcd per adapter. Only the atm0 has two atmsvcd processes.

      If the atmsvcd daemons exist, then try rebooting if possible. The adapter or the device driver may be hung. If the reboot fails to free up the ATM, contact your AIX support center if necessary.

5. The UNI version is defined at both the switch and the system client. The UNI version can be either 3.0 or 3.1. In addition, the system will set the UNI version to auto-detect. The ATM switch may not recognize or could be incompatible with the auto-detect function. Check the UNI version of the ATM adapter with the command lsattr -El atmx or via SMIT fastpath with smit chg_atm. Try changing it to the same fixed value as that of the ATM switch.

6. Problems of intermittent communications loss or the inability to ping on reboot are often caused by defects or incompatibilities with non-IBM ATM switches. We suggest you upgrade to the latest fileset levels whenever possible. In the U.S., please call 1-800-CALLAIX to obtain these.

[ Doc Ref: 90605195514806     Publish Date: Jan. 31, 2001     4FAX Ref: 7467 ]