10-31-2013 01:41 AM - edited 03-07-2019 04:20 PM
Hi,
I have a strange situation. I have 15 pcs of C2960S, all of them connected to a 4500-X by 10 Gb fiber. All the switches are in VLAN 9 - the have 192.168.1.x/24 IP addresses. In VLAN 1 - 172.16.5.0/24 I have CPI v 1.3
6 switches are not reachable by CPI, and indeed, I can't ping CPI from those switches and viceversa.
The configs for all 15 switches are identical.
What I noticed wierd on non-reacheble switches is the arp table. I put a paste from both working an non-working swithes. (172.16.5.75 -is the CPI server)
1. Working:
Switch8#sh arp
Protocol Address Age (min) Hardware Addr Type Interface
Internet 192.168.1.10 - f029.29bc.8f41 ARPA Vlan9
Internet 192.168.1.1 0 4c4e.3597.4cbf ARPA Vlan9
Internet 172.16.5.75 91 4c4e.3597.4cbf ARPA Vlan9
2. Non working:
Switch7#sh arp
Protocol Address Age (min) Hardware Addr Type Interface
Internet 172.16.5.75 5 000c.298c.fb42 ARPA Vlan1
Internet 192.168.1.1 0 4c4e.3597.4cbf ARPA Vlan9
Internet 192.168.1.9 - f029.2983.95c1 ARPA Vlan9
I don't know why in the non-working switch the host appears in VLAN1.
Please help!
Thanks a lot!
Adrian
10-31-2013 02:57 AM
could you please confirm whether all the interconnecting switch ports are configures as trunk
10-31-2013 03:19 AM
Yes, of course.
The TenGigas are "switchport mode trunk" and the others are:
"switchport access vlan x
switchport mode access"
In the meantime I noticed something: if I do clear arp, ping 172.16.5.75 twice it starts functioning, and the arp looks like:
Switch11#sh arp
Protocol Address Age (min) Hardware Addr Type Interface
Internet 192.168.1.1 0 4c4e.3597.4cbf ARPA Vlan9
Internet 192.168.1.13 - 8875.56b9.5841 ARPA Vlan9
which looks good, but not lasts forever, after a while stops working.
10-31-2013 07:42 PM
Hello Adrian,
It looks like the ARP entry for the 172.16.5.75 or the Mac Addres on the port are aging out, that's why you see it working and "after some time it stops working".
By the time that you experience the issue, check the "show mac-address interface
You can fix this issue (temporarily) by putting the ARP entry for this IP address
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