4507R - installing redundant supervisor module

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Mar 3rd, 2008
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when installing a second supervisor module in to a 4507 chassis which will become active / redundant?

is the sync between the supervisors automatic?

and what would happen if the second supervisor module already had configuration settings?


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lamav Mon, 03/03/2008 - 08:53
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When you insert a secondary supervisor module -- and high availability is enabled and verionsing disabled -- the active supervisor will continue being the active one and the 2 supervisors will communicate with each other via the backplane after the secondary has completed its initial hardware checks.

Because the active supervisor engine is already switching traffic on the backplane, no switching-bus diagnostics are run for the second supervisor engine because running diagnostics can disrupt the normal traffic. The second supervisor engine immediately enters standby mode. The active supervisor engine downloads the software image and configuration to the standby supervisor engine, if necessary. This is known as supervisor synchronization.

If high availability is enabled and versioning is disabled, the active supervisor will check the verion of IOS being run on the secondary module. If the 2 versions differ, the active supervisor will forcibly download its version of code to the new secondary sup, as well as the contents of its NVRAM. With versioning enabled, the 2 supervisors will be allowed to maintain different versions of code, as long as they are "compatible."

Also, when you hot insert or restart a second supervisor engine that becomes the standby supervisor engine, the active supervisor engine downloads the entire system database (FIBs, CEF tables, protocol databases) to the standby supervisor engine. Only after this global synchronization is completed, the active supervisor engine queues and synchronizes the individual updates to the standby supervisor engine to maintain "protocol state."

Check this link out.



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mikedelafield Tue, 03/04/2008 - 00:39
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thats excellent thanks

in redundant mode is it also possible to combine the 2 x 1GB uplinks on the supervisor to another 4507R? ie... to enable 2GB rather than 1GB between the switches?


lamav Tue, 03/04/2008 - 05:14
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Of course.

You create an etherchannel and bundle the 2 links in an etherchannel group. Typically, the uplink ports on the standby module are enabled, even in standby mode. But it really depends on the sup model itself.

So, you take one port on the active sup and another on the secondary sup and bundle them.





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