MPROUTE LOOPS TRYING TO INITIALIZE
APAR Identifier ...... PK25441 Last Changed ........ 06/10/06 MPROUTE LOOPS TRYING TO INITIALIZE Symptom ...... LP LOOP Status ........... CLOSED PER Severity ................... 2 Date Closed ......... 06/07/25 Component .......... 5735FAL00 Duplicate of ........ Reported Release ......... 520 Fixed Release ............ 999 Component Name TCP/IP V2 FOR V Special Notice Current Target Date .. Flags SCP ................... Platform ............ Status Detail: SHIPMENT - Packaged solution is available for shipment. PE PTF List: PTF List: Release 520 : UK16599 available 06/07/31 (0602 ) Parent APAR: Child APAR list: ERROR DESCRIPTION: MPROUTE initializes and goes into a CPU utilzation state. Traces indicate that MPROUTE is looping trying to send bad DATA Descriptor packets. A VMDUMP indicates that a bad MTU (0) was set incorrectly causing the problem to occur. LOCAL FIX: Change MTU= 0 statement in the MPROUTE CONFIG file to the correct value being used. PROBLEM SUMMARY: **************************************************************** * USERS AFFECTED: ALL USERS OF MPROUTE. * **************************************************************** * PROBLEM DESCRIPTION: * **************************************************************** * RECOMMENDATION: APPLY PTF * **************************************************************** When a user codes MTU=0, MPROUTE updates the interface control block MTU field with the value from the LINK statement in the TCPIP configuration. However, another field in the OSPF interface control block, which represents the maximum OSPF packet size and is based off the value of the MTU fails to get updated at the same time. This results in the interface control block having the correct MTU while the OSPF interface control block has a value of zero for the maximum packet size. When this problem occurs, neighbors will be stuck in state 32 with at least 1 outstanding LSA on the database summary list. The MPROUTE trace will show MPROUTE enter state 32 and then show the sending and receiving of empty database exchange packets with the database exchange packet from MPROUTE having the M bit set. PROBLEM CONCLUSION: The routine MPRGMTU, that sets the interface MTU from the LINK statement, was changed to also set the maximum OSPF packet size. THE FOLLOWING CHANGES HAVE BEEN MADE TO THE SYSTEM REFERENCE LIBRARIES: ***START PUBLICATION CHANGE************************************* PUBLICATION TITLE: z/VM V5R2.0 TCP/IP Messages and Codes RELEASE: V5R2.0 ORDER NUMBER: GC24-6124-01 ------------------------------------------- CHAPTER: 6 MPROUTE Messages ABSTRACT: Add the message DTCMPR8097I DTCMPR8097I MTU value of <mtu> was coded for interface <interface>. Default MTU of 576 will be used. Explanation: An invalid maximum transmission unit (MTU) was specified on the OSPF_INTERFACE, RIP_INTERFACE or INTERFACE statement in the MPROUTE CONFIG file, and the MTU was not specified on the corresponding LINK statement in the PROFILE TCPIP. The MTU value in the MPROUTE CONFIG file must be a number from 576 to 65535 (but cannot exceed the value specified on the LARGEENVELOPEPOOLSIZE statement), or the MTU value can be zero if the MTU is specified on the LINK statement. System Action: MPRoute uses the default MTU of 576 and continues. System Programmer Response: Specify a valid MTU value on the OSPF_INTERFACE, RIP_INTERFACE or INTERFACE statement in the MPROUTE CONFIG file, or specify an MTU of zero on the OSPF_INTERFACE, RIP_INTERFACE or INTERFACE statement in the MPROUTE CONFIG file and specify an MTU on the corresponding LINK statement in the PROFILE TCPIP. ***END PUBLICATION CHANGE*************************************** TEMPORARY FIX: COMMENTS: MODULES/MACROS: MPRGMTU MPRIFOPN MPROUTE MSMPROUT SRLS: GC24612401 RTN CODES: CIRCUMVENTION: MESSAGE TO SUBMITTER: