Connectivity Issue Shows No Internet Access

[Batelco]

Dear Community,

Recently connected an extended C3750 from an existing C3550 switch. the C3750 has IPbase OS but is currently used as L2 Switch. after configuration and testing, my windows 7 machines Network Adapter shows no network connection and loading URL pages takes longer than usual.

Network Environment:

a LAB of 20 Windows 7 machines connected to fast Ethernet ports in a retail store with BGP routing enabled on the C3550 switch to reach our HQ, therefore extended to a gigabit capable switch to enhance LAN performance. can't switch all machines to a single switch as we don't have in stocks a 48 port switch. they used to be connected to a dumb switch speed was slow but HTTP URLs open quickly.

Change Commited:

Installed and extended a newer switch thru Fabric port using Trunk mode.

Issue:

Clients loading pages takes longer on hosts connected to the extended switch C3750 than the old switch "C3550" getting "No Internet Connection in Network Icon". Also noticed the issue persist when restarting the desktop PC until a webpage loads completely and becomes cached.

Appreciate your feedback if you find any issues or unevenness from the configurations below.

Attached Configuration for both switches in separate files.

Kind Regards,

Sharaf, A

[Reza Sharifi]

Hi,

Can you delete this line form interface 1/0/25?

switchport trunk native vlan 2

and test again?

HTH

[Batelco]

---

@Reza Sharifi wrote:

Hi,

Can you delete this line form interface 1/0/25?

switchport trunk native vlan 2

and test again?

HTH

---

Hi Reza,

Thanks for your reply, if I delete it from interface 1/0/25, should I be deleting it from the other end "C3550 Gi0/2 as switchport trunk native vlan 2 is also configured there"?

[Reza Sharifi]

Hi,

Yes, delete it on both sides.

HTH

[Batelco]

last thing I configured before assuming network connection availability enhanced before I left the lab was "no ip route-cache" inside the interface vlan 2. I will wait for further usage and will apply it if received complaints. however, I am not certain it's the native vlan as I have configured the extended switch based on an existing configuration in a different site. but will surely take your reply into consideration. your feedback is appreciated :)

[Batelco]

Dear Reza,

The uplink on the main shows many updown lineproto from the main switch trunk interface"Gi0/2"  towards the extended switch "Gi1/0/25", but no updown lineproto on the interface on the other side. also attached show interface status for Gi0/2. Appreciate looking into it.

kind Regards,

Abdulla

[Batelco]

Dear Reza,

The link on the main switch shows many updown lineproto from the extended switch trunk interface"Gi0/2"  towards the extended switch "Gi1/0/25", but no updown lineproto on the interface from the other side "Gi1/0/25". also attached show interface status for Gi0/2. Appreciate looking into it but kindly note that there is a connection to external sites but unstable.

kind Regards,

Abdulla

[Batelco · Accepted solution]

Just in case someone stumbled across a similar issue. the link flap which was occurring excessively between the main branch switch and the newly installed one was caused by a hardware defect from the main switch as the other side of the link was not registering any flaps. I bypassed the trunking through fiber channel and crimped a cross-over Ethernet cable as the C3550 does not support auto MDIX like the newer models, connected each side of interface and before issuing no shut command I unplugged the fiber cable to ensure that STP would not interfere and block the Ethernet link. flaps are gone so it was either the pluggable fiber unit on C3550 or the controller that is running behind it that was malfunctioning. Other things that I applied as well is properly set VTP server and have the second side linked to it as client mode. ensured that keepalive settings are set to match each other. and removed native vlan. but main issue was a layer 1 issue.

Kind Regards,

Abdulla Sharaf