Dear All,
Two weeks ago we replaced our switches to new CBS350 devices and we segmented the network into several VLANs. As network core we're using 4 devices (2x CBS350-24XT and 2x CBS350-XTS) and these switches are used for InterVLAN routing.
Unfortunately, after these changes, starting routing between VLANs on hosts sometimes takes a very long time (up to several minutes) even though the devices almost immediately receive an IP address from DHCP server and don't have any problems with connecting to hosts within the their VLAN.
Example below - my computer (IP from DHCP 10.89.68.168, mask: 255.255.252.0, gateway: 10.89.71.254) located in VLAN 68 easily pings a host (10.89.70.2) that is also in this VLAN, but there is no connection both to the host from VLAN 66 (10.89.67.253, mask: 255.255.254.0, gateway: 10.89.67.254) and IP address of VLAN 68 gateway (core switch - 10.89.71.254).
I also noticed that when there's no communication between VLANs and with the core switch, the entry with the gateway address is not present in the ARP table on my computer (as if there was some MAC address conflict in the network?). For the test, I added a manual entry in the ARP table of my computer and when I have this setting, there are no problems (as if the core switches had a problem with broadcast their MAC address on the network?)
Of course, core switches have an IP address set in each VLAN and there's entry for every VLAN in IPv4 Forwarding Table.
PDC-CORE1#show ip interface
IP Address I/F I/F Status Type Directed Prec Redirect Status admin/oper Broadcast
------------------ --------- ---------- ------- --------- ---- -------- ------
0.0.0.0/32 oob UP/DOWN DHCP disable No enable Not received
10.89.1.254/24 vlan 1 UP/UP Static disable No enable Valid
10.89.67.254/23 vlan 66 UP/UP Static disable No enable Valid
10.89.71.254/22 vlan 68 UP/UP Static disable No enable Valid
10.89.75.254/22 vlan 72 UP/UP Static disable No enable Valid
10.89.79.254/22 vlan 76 UP/UP Static disable No enable Valid
10.89.200.254/24 vlan 200 UP/DOWN Static disable No enable Valid
10.90.69.254/23 vlan 168 UP/UP Static disable No enable Valid
10.90.71.254/23 vlan 170 UP/UP Static disable No enable Valid
10.90.73.254/23 vlan 172 UP/UP Static disable No enable Valid
Does someone had similar issue and can help me in that case? Many thanks in advance for every answer!
BR
