VLAN Communications Issues

[stonnet72]

Please note the following scenario:

- Site A is connected to Site B over Dark Fiber

- Site A = 192.168.1.x

- Site B = 192.168.2.x

- Site A has two VLAN's configured on the switch (3560)

VLAN 2 = 192.168.1.x

VLAN 3 = 192.168.2.x

- Site B's switch has all of its Gigabit ports (1 - 26) configured to be in VLAN 3 on Site A's switch (including the access port from Site B/Switch B to Site A/Switch A)

- Did not configure Switch B with IP routing functionalities as the entire switch is in VLAN 2 and you do not need to enabled routing within a VLAN, right?

- placed a laptop on both ends with IP's respective to that subnet (or VLAN 2)

- made sure the ports were in VLAN 2

- tried to ping each other over the fiber, ping did not work

- Ping did not work from clients

- Ping did not work from switch to switch

- I can not telnet to management IP for the switch in Site B

- however, "sho CDP neigh details" sees the swtich over fiber

- this scenario worked when I configured a test run of this set up via ethernet cable in my lab

- Can someone explain to me what I am missing? I am sure it is some small.

Thank you very much

[sundar.palaniappan]

Hi,

There's a contradiction in your posting. You say all ports in switchB is on VLAN 3 but all the other subsequent statements indicate the SiteB/SwitchB is on vlan2. Is this a typo or error in config. Can you clarify?

HTH,

Sundar

[stonnet72]

sorry about the mistake in explaining my issue

- Site B/Switch B ports are in VLAN 3 (192.168.2.x)

- Site A/Switch A is configured with two VLANS

- VLAN 2 = 192.168.1.x

- VALN 3 = 192.168.2.x

- Laptops have been placed in a Gigport on Site B/Switch B (lets say Gi0/3 VLAN 3)

- placed laptop on Site A/Switch A in a Gigport (lets say Gi0/3)

- in addition I configured Site A/Switch A Gi0/3 to partake in VLAN 3 (192.168.2.x)

- gave IP addresses to both laptops x.2.16 and x.2.17

- no ICMP communication between the two however the interface registers input and I think output packets.

Does this help clarify things?

[m-haddad]

Hello,

Since you have multiple VLANs on Site B switch you have to configure the fiber interface as trunk. Once you configure it as trunk you can pass traffic.

Let me know if this helps and rate plz,

[stonnet72]

M-Haddad,

Site A is configured with multiple VLAN's Site B is not. I am very sorry for not explaining as succinct as possible (I am not test writer that's for sure). So sense Site A/Switch A has multiple VLAN's I have to configure it to Trunk? Hmmmmm. Why would I need to Trunk the access link up to Site B/Switch B when ICMP communication is only taking place in one VLAN (vlan 3) and not outside of it. Please help me understand. I did not have to do this during my testlab scenario. Other than making sure ports were in its necessary VLAN, everything worked fine.

[sundar.palaniappan]

Can you post the following output from both switches.

1. show vlan

2. show run int g0/3

3. show int g0/3

4. show int vlan3 on switchA & show run int vlan3

Are the PCs the configured with the correct default gateway address, 192.168.1.x?

[m-haddad]

Well, as long as I understand on Site B all ports are on the same VLAN3. And you set the port going to Site A on vlan3 as well. Same for the port going from Site A to Site B you set it on VLAN3.

Is that right?

Can you paste the config for switch in SiteA and B

[stonnet72]

Please take a look at the config file to see if I am mistaken or missing something in my configuration.

Thanks

[sundar.palaniappan]

Do you have vlan 2 created in both switches. Can you post the output of show vlan on both switches?

Is the gig interface up between the switches up and do you see input/output packets on them?

[stonnet72]

After performing a side by side comparison of the config files i determined that SiteB/SwitchB did not have an IP address associated with VLAN 2. Once I configured an IP address on SiteB/SwitchB for VLAN 2, that was in the same range as was in the same IP range for SiteASwitchA IP address. I was able to send ICMP packets from the client on Switch B/Site B to Switch A/Site A. I did not think I had to do that. Can anyone explain to me why?

[Edison Ortiz · Accepted solution]

Jonathan,

From the config you posted:

SwitchB:

interface Vlan1

description Management_IP_For_SiteB_Switch

ip address 192.168.2.11 255.255.255.0

SwitchA:

interface Vlan2

ip address 192.168.2.3 255.255.255.0

ip helper-address 192.168.2.10

Do you see the problem there ? :)

You created a management interface on SwitchB but associated the ip that belongs to VLAN2.

That's the reason after assigning an IP within 192.168.2.0 /24 subnet to VLAN2, you are able to ping.

You have ip routing enabled on switchB and if you want to treat this switch as an access switch, I recommend typing

(config)#no ip routing

Please rate helpful posts.

Thanks

[stonnet72]

Ed,

As usual you are correct. I do not know, how I could have overlooked something as minor as that. As you stated, I:

- disabled ip routing

- I changed mgmt VLAN IP address

- Switch B is now an access Switch instead of a routing switch. Thanks Ed (what took you so long anyway...lol)