[asterisk-ss7] MTP2 CRC errors resulting in flapping link

[Kai Militzer]

Hello list,

I have a really big problem with the loss of my MTP-link because of CRC 
errors. I constantly see messages like:

Jul  3 13:46:06 NOTICE[18867]: mtp.c:1496 mtp_thread_main: Full Zaptel 
input buffer detected, incoming packets may have been lost on link 'l1'.
Jul  3 13:46:06 NOTICE[18867]: mtp.c:1543 mtp_thread_main: Empty Zaptel 
output buffer detected, outgoing packets may have been lost on link 'l1'.
Jul  3 13:46:06 NOTICE[18867]: mtp.c:1227 mtp2_read_su: MTP2 CRC error 
(CRC=0xba93 != 0xf0b8) on link 'l1'.
Jul  3 13:46:06 NOTICE[18867]: mtp.c:1442 mtp_thread_main: Excessive 
poll delay 57756!
Jul  3 13:46:06 NOTICE[18867]: mtp.c:1496 mtp_thread_main: Full Zaptel 
input buffer detected, incoming packets may have been lost on link 'l1'.
Jul  3 13:46:06 NOTICE[18867]: mtp.c:1543 mtp_thread_main: Empty Zaptel 
output buffer detected, outgoing packets may have been lost on link 'l1'.
Jul  3 13:46:06 NOTICE[18867]: mtp.c:1227 mtp2_read_su: MTP2 CRC error 
(CRC=0x9b7c != 0xf0b8) on link 'l1'.

And on the other side of the SS7 link on an Alcatel switch there are 
CRC16 messages logged. I also see

Jul  3 13:45:42 WARNING[18867]: chan_ss7.c:3598 monitor_main: MTP is now 
DOWN on link 'l1'.

Jul  3 13:45:47 WARNING[18867]: chan_ss7.c:3594 monitor_main: MTP is now 
UP on link 'l1'.
Jul  3 13:45:47 WARNING[18867]: chan_ss7.c:3601 monitor_main: MTP is now 
INSERVICE for linkset 'siuc'.

This makes the connection very unreliable.

Any idea how to solve this problem?

My system/kernel is:

Linux ss7-gate 2.6.8-3-686-smp #1 SMP Thu Feb 9 07:05:39 UTC 2006 i686 
GNU/Linux

debian kernel package.

ss7-gate:~# cat /proc/cpuinfo
processor       : 0
vendor_id       : GenuineIntel
cpu family      : 15
model           : 4
model name      : Intel(R) Pentium(R) 4 CPU 3.00GHz
stepping        : 3
cpu MHz         : 3012.221
cache size      : 2048 KB
physical id     : 0
siblings        : 2
fdiv_bug        : no
hlt_bug         : no
f00f_bug        : no
coma_bug        : no
fpu             : yes
fpu_exception   : yes
cpuid level     : 5
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge 
mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe lm 
pni monitor ds_cpl tm2 cid
bogomips        : 5947.39

processor       : 1
vendor_id       : GenuineIntel
cpu family      : 15
model           : 4
model name      : Intel(R) Pentium(R) 4 CPU 3.00GHz
stepping        : 3
cpu MHz         : 3012.221
cache size      : 2048 KB
physical id     : 0
siblings        : 2
fdiv_bug        : no
hlt_bug         : no
f00f_bug        : no
coma_bug        : no
fpu             : yes
fpu_exception   : yes
cpuid level     : 5
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge 
mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe lm 
pni monitor ds_cpl tm2 cid
bogomips        : 6012.92

ss7-gate:~# free
              total       used       free     shared    buffers     cached
Mem:       1035724    1029592       6132          0      82176     866152
-/+ buffers/cache:      81264     954460
Swap:       979956          0     979956

ss7-gate:~# cat /proc/interrupts
            CPU0       CPU1
   0:  981039926          0    IO-APIC-edge  timer
   1:       1649          0    IO-APIC-edge  i8042
   7:          2          0    IO-APIC-edge  parport0
   9:          0          0   IO-APIC-level  acpi
  14:  180901833        345    IO-APIC-edge  ide0
  50:          0          0         PCI-MSI  pciehp
177:          0          0   IO-APIC-level  uhci_hcd
185:          0          0   IO-APIC-level  uhci_hcd, ehci_hcd
193:  980184484          0   IO-APIC-level  uhci_hcd, wct2xxp
201:          0          0   IO-APIC-level  uhci_hcd
209:    2637787          0   IO-APIC-level  eth1
225:   23187346          0   IO-APIC-level  eth0
NMI:          0          0
LOC:  981005852  981005848
ERR:          0
MIS:          0

Regards,
Kai

-- 
Kai Militzer                 WESTEND GmbH  |  Internet-Business-Provider
Technik                      CISCO Systems Partner - Authorized Reseller
                              Lütticher Straße 10      Tel 0241/701333-14
km at westend.com               D-52064 Aachen              Fax 0241/911879