About MTU of CSC-SSM on ASA

[STM_51]

I  am using a ASA with CSC-SSM.

Is it correct that MTU of eth0 is 1796?
Is there an influence in the communication?

#@ Ethernet Interface Information
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eth0      Link encap:Ethernet  HWaddr 00:00:00:02:00:02 
          UP BROADCAST RUNNING MULTICAST  MTU:1796  Metric:1
          RX packets:200024351 errors:0 dropped:0 overruns:0 frame:0
          TX packets:215388556 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:4113709994 (3.8 GiB)  TX bytes:3588690813 (3.3 GiB)
          Base address:0xcc00 Memory:f8100000-f8120000

eth1      Link encap:Ethernet  HWaddr 00:19:E8:2B:C9:7A 
          inet addr:10.21.1.63  Bcast:10.21.1.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:10705829 errors:0 dropped:0 overruns:0 frame:0
          TX packets:1457926 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:100
          RX bytes:1599212156 (1.4 GiB)  TX bytes:185586566 (176.9 MiB)
          Base address:0xbc00 Memory:f8200000-f8220000
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＝＝＝＝＝ System info ＝＝＝＝＝＝
ASA Version 7.2(4)30
Device Manager Version 5.2(4)

Model:              ASA-SSM-CSC-10
Hardware version:   1.0
Firmware version:   1.0(11)2
Software version:   CSC SSM 6.3.1172.0
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Best Regards,

[PAUL GILBERT ARIAS]

somehow that interface has that MTU value. Is that the interface of the ASA itself?

[STM_51]

Thank you for your reply.

No. The interface is CSC-SSM module's inter

face on ASA.

eth1 is a port of  RJ-45type on CSC-SMS.

the interface has IP address and MTU:1500.

I think eth0 is a internal BUS to ASA.

eth0 has no IP address and MAC address is

00:00:00:02:00:02.

[PAUL GILBERT ARIAS]

yes, eth1 is the management interface for the module. eth0 should be the one on the backplane of the ASA but still don't know for sure why the MTU is higher.

I checked another CSC-SSM on a ASA5510 and it has the same value. No idea why.

[STM_51]

Hi Paul

Thank you for confirming it.

Does not your ASA(CSC)  has a communication trouble?

For example, DELAY  or Packet Loss ....

[PAUL GILBERT ARIAS · Accepted solution]

no troubles so far. are you sending high loads of traffic to the CSC?

[STM_51]

I don't send high loads of traffic. Your CSC's eth0 is 1796 , isn't it?

So, MTU:1796 is no problem, isn't it?

Our trouble is occurred on communication to a part of URL.

If the MTU value has some problems, it is occurred trouble on all communications, I think.

Maybe this MTU is no problem.

I want to think it. 

[PAUL GILBERT ARIAS · Accepted solution]

same MTU but no problems. I don't think MTU is your issue.

[STM_51]

Thank you so much.