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SVI not responding

Vamsi Pinnaka
Level 1
Level 1

Hi all,

I have very strange problem with SVI. here is the brief description.

My customer is having two ISP's. ISP 1 is MPLS and ISP 2 is Internet. Please look at the attachment for better understanding of the topology.

On the router, default router is configured to ISP 2 for Internet and static routes are configured to ISP 1 for intranet. This router is 871, which comes with 5 physical ports. 0 to 4 are LAN ports and 5 is WAN port. Due to some reasons my customer don't want to use WAN port. So they configured SVI (Vlan 1) and F0 for connectivity. This SVI is gateway for LAN to reach Internet and intranet. This entire network is in same subnet (LAN, Router and ISP's). Issue is, after every 5 to 6 mints router is unreachable. but i can access it via console. interface status also show's up for both Vlan 1 and F0. If i do "shut" and "no shut" on interface F0, it works for couple of mints and again unreachable. But if i remove SVI and configure WAN (F4) interface, it works without any problem. Currently I configured SVI with IP address only, not even hostname or static routes, but still it goes down after couple of mints.

Last week i took this router from customer place and configured it in my office, it worked perfectly. If I place this router at customer site, it goes unreachable in couple of mints. I even replaced the router with brand new. Your help is greatly appreciated.....

15 Replies 15

Guys,

Its working now. I saw "unknown protocol drops" in vlan1, so i though of disabling spanning-tree on switch and router.

below are my configuration

int f0

switchport mode access

switchport access vlan1

spanning-tree portfast

end

and on HP switch also, disabled spanning-tree. thanks guys.........

Regards,

Vamsi Pinnaka

Bangalore

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