Dave, It is my understanding that interfaces are set up in the same lan group if they are defined for the same subnet and the adapter can 'ping each other' (i.e, you can ping the address associated with interface A when pinging through interface B). Once they're in the same LanGroup they are considered backups for each other and will do ARP failover. So if your OSA9500LNK interface would go down, the IP addresses associated with it will remain accessible through one of the other links. When the original interface comes back up, the address moves back to that interface.
I believe the outgoing traffic is spread over the adapters you list, but don't quote me on that and that might be the case in your original config as well. On a site note, you might want to check your PORTFAST setting on the switch side (or the equivalent for your type of switch) if you want to rely on the LanGroup setup. Without PORTFAST we've seen the interface come back up after an outage, but in a separate LanGroup. HTH, Bart -----Original Message----- From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of Hansen, Dave L - Eagan, MN Sent: Friday, April 26, 2013 3:04 PM To: [email protected] Subject: Load Balancing and Interface Statements - LanGroup? Valued helpers, We are running z/OS v1R13 and I am now looking at LanGroups. We changed from DEVICE/LINK statements to INTERFACE statements in our TCP/IP Config. Now I have one LanGroup and one VipaOwner instead of four LanGroups and four VipaOwners. I have looked through the IP Config reference and guide and I didn't find anything on LanGroups. I looked in the IP System administrator's commands under the Netstat Devlinks report and it talks about the IPv4 LAN Group Summary. It says "The stack creates a LAN group when it detects redundant connectivity to a LAN". With DEVICE /LINK definitions: NETSTAT DEVL - LanGroup: 0001 Name Status ArpOwner VipaOwner ------- ------- ------------- -------------- OSA9100LNK ACT OSA9100LNK Yes LanGroup: 0002 Name Status ArpOwner VipaOwner ------- ------- ------------- -------------- OSA9000LNK ACT OSA9000LNK Yes LanGroup: 0003 Name Status ArpOwner VipaOwner ------- ------- ------------- -------------- OSA9300LNK ACT OSA9300LNK Yes LanGroup: 0004 Name Status ArpOwner VipaOwner ------- ------- ------------- -------------- OSA9200LNK ACT OSA9200LNK Yes With INTERFACE definitions: NETSTAT DEVL - LanGroup: 0001 Name Status ArpOwner VipaOwner ------- ------- ------------- -------------- OSA9500LNK ACT OSA9500LNK No OSA9600LNK ACT OSA9600LNK No OSA9400LNK ACT OSA9400LNK Yes OSA9700LNK ACT OSA9700LNK No Q). Do these new LAN group assignments and VipaOwner assignments have any impact on Load Balancing across the four OSAs? Should we be concerned about these changes? Thank you, Dave ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
