Catalyst 2950 Interfaces up during reboot

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Mar 12th, 2010
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Boot Loader (C2950-HBOOT-M) Version 12.1(11r)EA1

IOS (tm) C2950 Software (C2950-I6K2L2Q4-M), Version 12.1(22)EA12

cisco WS-C2950G-24-EI-DC (RC32300) processor (revision L0) with 19912K bytes of memory.



We have a redundent configuration with two 3640s connected to two 2950s, The 2950s are connect to each other.  The 3640s have a routed connection between each other running OSPF.  The layer 2 side is in a U configuration, 3640 to 2950 to 2950 to 3640. The 3640s connect to a cloud via OSPF.


During a reboot the 2950 switch will bring up the linkbeat on its interfaces, but it does not pass traffic.


The 3640 that is connected directly to the 2950 that is being rebooted sees the link beat come up and propegates this infomation to OSPF, but any traffic sent to the 2950 gets dropped because the IOS is not up yet.


Is there any way to prevent the sending of traffic to that switch until it is fully up?

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Ganesh Hariharan Fri, 03/12/2010 - 22:41
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Boot Loader (C2950-HBOOT-M) Version 12.1(11r)EA1

IOS (tm) C2950 Software (C2950-I6K2L2Q4-M), Version 12.1(22)EA12

cisco WS-C2950G-24-EI-DC (RC32300) processor (revision L0) with 19912K bytes of memory.



We have a redundent configuration with two 3640s connected to two 2950s, The 2950s are connect to each other.  The 3640s have a routed connection between each other running OSPF.  The layer 2 side is in a U configuration, 3640 to 2950 to 2950 to 3640. The 3640s connect to a cloud via OSPF.


During a reboot the 2950 switch will bring up the linkbeat on its interfaces, but it does not pass traffic.


The 3640 that is connected directly to the 2950 that is being rebooted sees the link beat come up and propegates this infomation to OSPF, but any traffic sent to the 2950 gets dropped because the IOS is not up yet.


Is there any way to prevent the sending of traffic to that switch until it is fully up?


Hi,


I would suggets in this case you connect the 2950 switches with both 3640 in full mesh, in this case if one 2950 switch goes down traffic coming from other 2950 will be forwarded to 3640, this will be the case if both the 2950 is genrateing the same type of lan traffic means to say same lan subnet.


This will create a full redundancy for you setup for traffic going out and coming in.


Hope to help !!


Ganesh.H

johnny.elliott Tue, 03/16/2010 - 09:09
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Unfortunately, this is a design that is already in live networks across about 70 sites, so it would not be physically changeable.  This would also introduce loops, which we are trying to stay away from, as we've been burned too many times with RSTP not being able to work around a particular issue, but that's another topic.

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