[j-nsp] EX4200: VC "incremental upgrade" ?

[Alexandre Snarskii]

Hi!

Silly question: is it possible to perform "incremental upgrade"
on ex-series virtual-chassis ? I.e., upgrade some switches
(using 'request system software add member NN'), switchover
master to 'upgraded' part, then upgrade remaining switches ? 

Juniper documentation is not so clear on this topic - on one hand we 
have command that allows upgrade of selected chassis member and KB10840 
suggests that "Virtual Chassis software can be upgraded for the entire VC 
or you can upgrade one individual member of the VC", on other - KB16756 
suggests that "for a standalone EX4200 switch to join an existing Virtual 
Chassis configuration, it had to be running the same version of software 
that was running on the Virtual Chassis master" and that since 10.0 master 
switch has ability to "ability to automatically update the software on a new 
member switch so that it can join the Virtual Chassis configuration"
(i.e., in this application fresh upgraded switch will be automatically
downgraded back to the version master running).

Or am I missing something ? 

-- 
In theory, there is no difference between theory and practice. 
But, in practice, there is.