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Switch Flooding
Hi
I have 34 5324 switches and they all are getting flooded if I plug in a 10mb half duplex device, if I plug the same device into a Cisco 2900 xl it works fine
How do I stop the flood , I have tried stom control and flow control,,,niether worked
Thks
Glenn
Mithrilhall
2 Intern
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128 Posts
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Posted December 21st, 2005 17:00
Have you tried changing the port speed on the switch where the 10mb half duplex device is plugged in to half-duplex?Mithrilhall
2 Intern
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128 Posts
590
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Posted December 21st, 2005 18:00
What type of device are you connecting to the switch?
I've seen problems with Wireless Netgear routers that would take down a network of Dell PowerConnect 33xx switches.It's an digital sign display and can only run at 10 half
Also I am running overlapping vlans and I notice rally slow speed when transfering files from one vlan to another
here is what I have
5324 switch
ports 1-10 vlan 2
ports 11-20 vlan 3
ports 21-24 vlan 4
2 can see 4 but not 3
3 can see 4 but not 2
4 can see everything
if I make it all one vlan the speed is about 10 times as fast as when I do overlapping vlans
I there a better fast way of doing this
Thks
Glenn
DELL-Cuong N.
1017 Posts
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Posted December 22nd, 2005 13:00
You mentioned that you are using overlapping VLAN? If so, then unfortunately your flood is occuring because of the way overlapping VLANs work and not because of the port speed or duplex. The problem is that overlapping VLAN require a use of a common VLAN that is used for all the ports that is different from the PVID of the port. Since the port will learn the MAC on the PVID and not on the common VLAN. Any packet sent on the common VLAN toward a destination ends up flooding because those packets are considered to be unknown unicast packets.There are a few alternatives to overlapping VLANs: 1) use a router to switch between VLANs; 2) use a switch that supports private edge VLAN (such as 34xx) and use PVLAN instead of overlapping VLANs to accomplish the same thing; 3) there are some other creative solutions using IP ACL and/or VLANs awareness at the PC/server but these methods are not as clean as option 1 and 2.There are some papers here that will explain both of these concepts - look for a paper of VLAN routing and one on PVLAN:Cuong.DELL-Cuong N.
1017 Posts
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Posted December 22nd, 2005 19:00
No you have a perfect solution with the 6024. You can use the 6024 routing function to route between VLANs. Check out the whitepapers I mention and look at the paper refering to VLAN routing. That's one of the option I mentioned. Also the 6024 have IP ACL which will also help you to control which IP address/port can talk to which other one. Check out the IP ACL functions on the 6024 for more info.
Cuong.
glenn77
1 Rookie
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68 Posts
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Posted December 21st, 2005 17:00
Yes
10 half
10 full
and auto as well as floww and backpressure settings
It totally kills my overlapping vlans