New Fiber connection

[diek]

I had a straight through long haul fiber connection provided by Charter from my 6509 to a 3750 working for years. Now we are changing to a ATT OPT-E-MAN fiber connection that uses ME3400 switches provided by ATT. With the new ATT fiber connection not all my devices on the 3750 are able to find there default gateway that is on the 6509. Most of the 48 computers work put on some I can ping the 3750 put I cannot ping the 6509 that is my gateway.

I put it back to the old Charter fiber and everything works. I change it back to the ATT fiber connection and computers that were working before are not not working and some that were not working are now working. I reset both switches and the computers that are not working and get the same problem. I can a move a compter that is not working to a port that a working computer was on and it still can not ping the gateway on the 6509.  Attached is a document with more description of the problem, a drawiing of the old and new way the fber connects, and the configuration of all the devies involved.

Thanks

Ken

[glen.grant]

  Sounds like maybe trunking isn't working right on the new setup .   Maybe thru the new 3400's . 

[diek]

I believe the trunking is working through the 3400's because everything works on the 3560 switch that is directly attaced to the 3400. Its only on the 3750 that is attached to the 3560 that I am having this problem. The problem would seem to be  trunking between the 3560 and the 3750. I now have an IP address assigned to default VLAN 1 on all the switches and use the default-gateway IP address of VLAN 1. I use VLAN 1 as my management VLAN on my network for CiscoWorks to use to manage all my switches and routers. I am thinking of adding a IP address for my VLAN 4 which is used by all the computers at the remote site and changing the default-gateway IP address to VLAN 4 gateway address. I have another remote site on a T1 using Cisco 1721 routers that I have set up that way but not usig trunking on it. 

[diek]

I removed the trunking and it did the same thing. I am calling ATT today.

[diek]

I found out that ATT has a default limit of 50 MAC addresses that can be increased to a maximum of 100 by paying a higher monthly fee. That was the reason I could not get all 90 of my network attached devices up. I changed my 6509 port connection to the ATT M3400 router to a Layer 3 connection. I assigned an IP address to it and to the 3560 port at the remote end.