Hello everyone!
The problem:
We have about 1500 access switches with managment vlan.
Network scheme is attached below.
ARP aging time is not reset to zero with existing traffic in management vlans. We have OpenNMS which pings hosts every minute + takes readings via SNMP. After the time expires (4:00 hours), the arp entry disappears and the host becomes inaccessible from 5 to 60 seconds, after which the arp entry reappears.
VSS#show ip arp vlan 204
Protocol Address Age (min) Hardware Addr Type Interface
Internet 172.16.131.1 - 5897.bdf1.5940 ARPA Vlan204
Internet 172.16.131.51 248 001e.589e.f690 ARPA Vlan204
Internet 172.16.131.19 242 04bf.6d1f.028e ARPA Vlan204
Internet 172.16.131.14 228 d8fe.e387.8400 ARPA Vlan204
VSS:
show version
Cisco IOS Software, c6880x Software (c6880x-ADVENTERPRISEK9-M), Version 15.4(1)SY2, RELEASE SOFTWARE (fc4)
interface Port-channel1
description Agg1 MEC
switchport
switchport mode trunk
switchport trunk allowed vlan 204,xxx,xxx,xxx,xxx,xxx
switchport nonegotiate
mtu 9216
logging event link-status
load-interval 30
platform qos trust cos
interface TenGigabitEthernet1/1/2
description AGG1 te4-5
switchport
switchport mode trunk
switchport trunk allowed vlan 204,xxx,xxx,xxx,xxx,xxx
switchport nonegotiate
mtu 9216
logging event link-status
logging event trunk-status
logging event bundle-status
load-interval 30
platform qos trust cos
channel-protocol lacp
channel-group 1 mode active
interface TenGigabitEthernet2/1/2
description AGG1 te4-6
switchport
switchport mode trunk
switchport trunk allowed vlan 204,xxx,xxx,xxx,xxx,xxx
switchport nonegotiate
mtu 9216
logging event link-status
logging event trunk-status
logging event bundle-status
load-interval 30
platform qos trust cos
channel-protocol lacp
channel-group 1 mode active
interface Vlan204
description Metro-PE
ip address 172.16.131.1 255.255.255.192
ip access-group acl_metro-out out
no ip redirects
no ip unreachables
no ip proxy-arp
Arp aging time : 4 hours
Mac aging time: 6 hours
What could be the problem?
Thanks,
Aleks
