Replacing two SUP720-BASE with two SUP720-3B in CAT 6500 chassis

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Mar 17th, 2009
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I have never done this before, but will this work.

Will the switch tolerate a SUP720-BASE and a SUP720-3B to be in the same switch for a short period of time.

Customer wishes to replace two SUP720-BASE with two SUP720-3B without any downtime or maintenance window.

Ofcourse IOS will be same.

Procedure we plan to follow:


1. Remove standby SUP 720-BASE (Slot 8)

2. replace with SUP-720-3B ( Slot 8 )

3. wait for sync and status to return as good HA state

4. perform a soft sup switch command

5. Remove 720-Base ( Slot 7)

6. replace sup with 720 3B ( Slot 7)

7 wait for ok status

8 Perform soft sup switch to return to normal

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Overall Rating: 4 (1 ratings)
Giuseppe Larosa Wed, 03/18/2009 - 01:16
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Hello Alphonse,

SSO requires the two supervisors to be of the same model.

RPR guidelines say that if the two supervisors are not identical one of the two will be kept in reset state


actually the same is written in HW restrictions of SSO

I would negotiate a maintanance window

point 3 should not happen.

And then if you remove the active sup while the new inserted one is in reset state you have out of service for sure.

I would:

remove one Sup 720

some hours later during maintanance I will insert sup 720 3b

remove sup 720

insert second 720 3B

hope to help


Leo Laohoo Wed, 03/18/2009 - 15:07
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Is your new Sup blade have the same IOS as the master?

What is your Test Verification Plan?

What is your Backout Procedure?

What is your Window?


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