Solved: Re: Daisy Chained switches VLAN broken with strange workaround.

Kyndall Taylor · ‎05-01-2020

I have purchased 8 2960x's with the same software version. Both have the same VLAN config.

VLAN 1 - 172.18.x.x/24

VLAN 2 - 10.16.x.x/24

ip routing enabled via CLI command

On both of the different setups, the first switch has an IP address VLAN1 172.18.x.1 and VLAN2 is 10.16.x.1

The first 4 are in a 'star' config with the other 3 running back to one switch via fiber trunks. Each additional switch has an IP address on VLAN1 172.18.x.2, .3, .4, everything pings on both VLANs at all times. All VLAN 2 devices on all switches have 10.16.x.1 as their gateway address. Works OK.

The other setup with the other 4 switches is daisy chained using SFP fiber trunks between the switches. Same address scheme, each additional switch has an IP address on VLAN1 172.18.x.2, .3, .4. Again, all VLAN 2 devices on all switches have 10.16.x.1 as their gateway address. VLAN 1 devices still always ping and never fail.

Every 2-3 days VLAN 2 just stops working, even at the local switch. Devices on the local switch can't be pinged must less devices from one switch to another. I go into the CLI on each switch, the ARP shows the VLAN2 devices, ip device track also shows the IP of each device on the port. I can't ping the device locally from the CLI. I saw after an exhaustive search on Google that the solution or workaround was to goto each switch's CLI and ping the broadcast address on the VLAN that was not working, so I ping 10.16.x.255 and all of the sudden the devices start responding again. I have to do this every couple of days. What is going on here?

Thanks for your time

Reza Sharifi · ‎05-01-2020

Can you remove this command from the ports with connected devises and retest?

ip device tracking maximum 10

Also,

The other switches do not have a gateway for the default VLAN1, they just have their own IP for VLAN1 so I can telnet to them. The ping traffic appears to cross the default VLAN 1 with no issues.

This is correct for hosts, but say the switch in the middle of the diagram does not have a gateway, that switch can only access the local subnet, which is vlan 1 and not 2. So, if you want to ping any device in vlan 2, from that switch, it needs default-gateway.

HTH

View solution in original post

Reza Sharifi · ‎05-01-2020

I have to do this every couple of days. What is going on here?

You should not need to do that. Something else is wrong? Could it be that the end device go to hibernate and you have to wake them up in order to ping them?

HTH

Kyndall Taylor · ‎05-01-2020

Thanks for the reply. It's affecting all of the devices on VLAN 2 on each switch , which includes computers and cameras. I wouldn't think all of them are going to sleep. It's a pretty simple setup (or at least I thought it was). The only address on VLAN 2 that always pings from any switch consistently is the VLAN 2 gateway address (10.16.x.1) which is configured on the very first switch. I can ping that address from any switch's CLI even when I cant ping local IPs on the same switch.

Reza Sharifi · ‎05-01-2020

Can you put together a simple diagram of the network and indicate where the gateway for each vlan is and post it here?

Do you have both gateways for both vlans configured on the same switch? If not, trying making only one of the switches the gateway for both vlans and test again.

HTH

Kyndall Taylor · ‎05-01-2020

Here is the diagram. I have an IP on each switch on the default VLAN where I can telnet into it

Reza Sharifi · ‎05-01-2020

Thanks for the diagram and the info. This all looks correct to me. What is the version of the software running on the switch (far left) with both SVIs? Also, can you post "sh run" from that switch?

Do all the other switches have a default-gateway configured pointing to 172.18.3.1?

HTH

Kyndall Taylor · ‎05-01-2020

The other switches do not have a gateway for the default VLAN1, they just have their own IP for VLAN1 so I can telnet to them. The ping traffic appears to cross the default VLAN 1 with no issues. Here is the other info:

Switch Ports Model SW Version SW Image
------ ----- ----- ---------- ----------
* 1 52 WS-C2960X-48FPS-L 15.2(4)E8 C2960X-UNIVERSALK9-M

BR_48_21#sh run
Building configuration...

Current configuration : 16449 bytes
!
! Last configuration change at 18:54:15 UTC Thu Apr 30 2020
! NVRAM config last updated at 17:03:17 UTC Thu Apr 30 2020
!
version 15.2
no service pad
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname BR_48_21
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
switch 1 provision ws-c2960x-48fps-l
!
!
ip routing
!
crypto pki certificate pool
**I DELETED THIS DATA FOR SPACE PURPOSES
quit
!
spanning-tree mode rapid-pvst
spanning-tree extend system-id
!
vlan internal allocation policy ascending
!
!
interface FastEthernet0
no ip address
no ip route-cache
shutdown
!
interface GigabitEthernet1/0/1
switchport access vlan 2
switchport mode access
ip device tracking maximum 10
!
interface GigabitEthernet1/0/2
ip device tracking maximum 10
!
interface GigabitEthernet1/0/3
ip device tracking maximum 10
!
interface GigabitEthernet1/0/4
ip device tracking maximum 10
!
interface GigabitEthernet1/0/5
ip device tracking maximum 10
!
interface GigabitEthernet1/0/6
ip device tracking maximum 10
!
interface GigabitEthernet1/0/7
ip device tracking maximum 10
!
interface GigabitEthernet1/0/8
switchport access vlan 2
ip device tracking maximum 10
!
interface GigabitEthernet1/0/9
switchport access vlan 2
ip device tracking maximum 10
!
interface GigabitEthernet1/0/10
switchport access vlan 2
ip device tracking maximum 10
!
interface GigabitEthernet1/0/11
switchport access vlan 2
ip device tracking maximum 10
!
interface GigabitEthernet1/0/12
switchport access vlan 2
ip device tracking maximum 10
!
interface GigabitEthernet1/0/13
ip device tracking maximum 10
!
interface GigabitEthernet1/0/14
ip device tracking maximum 10
!
interface GigabitEthernet1/0/15
ip device tracking maximum 10
!
interface GigabitEthernet1/0/16
ip device tracking maximum 10
!
interface GigabitEthernet1/0/17
ip device tracking maximum 10
!
interface GigabitEthernet1/0/18
ip device tracking maximum 10
!
interface GigabitEthernet1/0/19
ip device tracking maximum 10
!
interface GigabitEthernet1/0/20
ip device tracking maximum 10
!
interface GigabitEthernet1/0/21
ip device tracking maximum 10
!
interface GigabitEthernet1/0/22
ip device tracking maximum 10
!
interface GigabitEthernet1/0/23
switchport access vlan 2
ip device tracking maximum 10
!
interface GigabitEthernet1/0/24
ip device tracking maximum 10
!
interface GigabitEthernet1/0/25
ip device tracking maximum 10
!
interface GigabitEthernet1/0/26
ip device tracking maximum 10
!
interface GigabitEthernet1/0/27
ip device tracking maximum 10
!
interface GigabitEthernet1/0/28
ip device tracking maximum 10
!
interface GigabitEthernet1/0/29
ip device tracking maximum 10
!
interface GigabitEthernet1/0/30
ip device tracking maximum 10
!
interface GigabitEthernet1/0/31
ip device tracking maximum 10
!
interface GigabitEthernet1/0/32
ip device tracking maximum 10
!
interface GigabitEthernet1/0/33
ip device tracking maximum 10
!
interface GigabitEthernet1/0/34
ip device tracking maximum 10
!
interface GigabitEthernet1/0/35
ip device tracking maximum 10
!
interface GigabitEthernet1/0/36
ip device tracking maximum 10
!
interface GigabitEthernet1/0/37
ip device tracking maximum 10
!
interface GigabitEthernet1/0/38
ip device tracking maximum 10
!
interface GigabitEthernet1/0/39
switchport access vlan 2
ip device tracking maximum 10
!
interface GigabitEthernet1/0/40
switchport access vlan 2
ip device tracking maximum 10
!
interface GigabitEthernet1/0/41
switchport access vlan 2
ip device tracking maximum 10
!
interface GigabitEthernet1/0/42
ip device tracking maximum 10
!
interface GigabitEthernet1/0/43
ip device tracking maximum 10
!
interface GigabitEthernet1/0/44
ip device tracking maximum 10
!
interface GigabitEthernet1/0/45
ip device tracking maximum 10
!
interface GigabitEthernet1/0/46
ip device tracking maximum 10
!
interface GigabitEthernet1/0/47
ip device tracking maximum 10
!
interface GigabitEthernet1/0/48
ip device tracking maximum 10
!
interface GigabitEthernet1/0/49
switchport mode trunk
!
interface GigabitEthernet1/0/50
switchport mode trunk
!
interface GigabitEthernet1/0/51
switchport mode trunk
!
interface GigabitEthernet1/0/52
switchport mode trunk
!
interface Vlan1
ip address 172.18.3.1 255.255.255.0
!
interface Vlan2
ip address 10.16.8.1 255.255.255.0
!
!
ip http server
ip http secure-server
!
!
!
line con 0
exec-timeout 180 0
password
login
line vty 0 4
exec-timeout 180 0
password
login
line vty 5 15
password
login
!
ntp server pool.ntp.org
!
!
pnp profile pnp_cco_profile
transport https host devicehelper.cisco.com port 443
end

BR_48_21#

Reza Sharifi · ‎05-01-2020

Can you remove this command from the ports with connected devises and retest?

ip device tracking maximum 10

Also,

The other switches do not have a gateway for the default VLAN1, they just have their own IP for VLAN1 so I can telnet to them. The ping traffic appears to cross the default VLAN 1 with no issues.

This is correct for hosts, but say the switch in the middle of the diagram does not have a gateway, that switch can only access the local subnet, which is vlan 1 and not 2. So, if you want to ping any device in vlan 2, from that switch, it needs default-gateway.

HTH

Kyndall Taylor · ‎05-01-2020

Ok Thanks for your help. I will add that and see what happens. It's strange that I can ping across switchs (VLAN2) sometimes but then it breaks. Anyway, I will add that this weekend and retry. Thanks again

Kyndall Taylor · ‎05-04-2020

Weird, I removed the ip device track from the ports and the VLAN issue cleared up, (or appeared to). I will monitor it and see if it breaks again. Thanks again for all your help.

Reza Sharifi · ‎05-04-2020

Glad to help. Thanks for the feedback!