Network Access/Connectivity Issue

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Jul 2nd, 2009
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Hello. I have a problem with my network and i would like to ask for some info. I have 4 cisco catalyst switches 2960G each of them serves a rack of servers. They all end up (with trunk ports) to two 4507 R-E switches configured for GLBP .All vlans and network ping and access each other through this GLBP and work fine. However some times connectivity is lost. For example i have a 10.10.10.210/24 server trying to backup to a 10.20.10.50/24 server. The connection from time to time gets lost. If i repair the network connection in Windows it gets back up. However if i continuously ping the backup server it never drops but i cannot keep pinging forever. Any help would be appreciated. Thanks a lot in advance.

Correct Answer by Joseph W. Doherty about 7 years 10 months ago

Because of your mention of "However if i continuously ping the backup server it never drops . . .", and your description of dual L3 swithes, I'm wondering if you're bumping into a unicast flooding issue. You might review http://www.cisco.com/en/US/products/hw/switches/ps700/products_tech_note09186a00801d0808.shtml.

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Giuseppe Larosa Thu, 07/02/2009 - 12:58
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Hello Theofanis,


what linecards are on the 4507 R-E?


we faced performance issues with 4548 48GE linecards they have 6GE access to the backplane and each group of 8 ports 1-8, 9-16 and so on shares a single ASIC with 1GE rx/tx limit.


Hope to help

Giuseppe


tkatsiaounis Fri, 07/03/2009 - 03:39
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Yes we do have the 4548 48port GE cards. What did you do to solve the problem??

Basicly i have 4 linecards and each of the four etherchannel trunk ports (from 2960 to 4507) goes to one port on different linecards. For example SWA etherchannel 21 to 24 port 21 goes to 4507A 1/1 port 22 goes to 4507A 5/1 port 23 goes to 4507B 1/1 and port 24 goes to 4507B 5/1.

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Joseph W. Doherty Fri, 07/03/2009 - 04:03
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Because of your mention of "However if i continuously ping the backup server it never drops . . .", and your description of dual L3 swithes, I'm wondering if you're bumping into a unicast flooding issue. You might review http://www.cisco.com/en/US/products/hw/switches/ps700/products_tech_note09186a00801d0808.shtml.

tkatsiaounis Sat, 07/04/2009 - 04:26
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I have tried to increase the mac address aging time (from 300 to 14400 secs) as the document you proposed suggests but still no luck. The backup fails.

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