[c-nsp] OIR in 6500/7600

[Tassos Chatzithomaoglou]

The 6500/7600 chassis has three pins in each slot that during insertion get connected one by one (larger to smaller) to 
the module. The first one starts the bus stall and the last one stops the bus stall.

I had problems when inserting too slowly the modules (the bus stall was lasting for more time). You just need to find 
the right speed.

Keep in mimd that DFC equipped modules do not have this problem. According to Cisco:

"The addition of a DFC module effectively disconnects a module from the Data Bus. As such, a DFC-enabled module is not 
subject to the bus stall mechanism that occurs when a module is inserted or removed from the chassis. Throughout these 
Online Insertion and Removal (OIR) events, the Data Bus is temporarily paused for just enough time to ensure that the 
insertion/removal process does not cause any data corruption on the backplane. This protection mechanism causes a very 
brief amount of packet loss (sub-second, but dependent on the time it takes to fully insert a module). A module with a 
DFC onboard is not directly affected by this stall mechanism and does not have any packet loss on OIR."

--
Tassos

Peter Taphouse wrote on 10/11/2008 17:04:
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> Hi,
> 
> I've got a couple of new line cards that I would like to stick in a
> production 7606.  When these were in the lab I tried OIR with decent
> success, but now the routers are production I'm a bit nervous of doing
> an OIR on these.
> 
> - From what I've read there are the three pins that cause the bus stall
> and recovery, and fairly frequently the reload.  If I were to "no power
> enable module X" for the appropriate slot, will this allow me to insert
> the card without having to worry about the bus stall and potential
> reload, or are those pins powered/effective regardless of the state of
> power to a particular slot?
> 
> Does anyone have any useful advice/experience with adding new modules to
> 6500/7600s?
> 
> Cheers,
> 
> - --
> Peter Taphouse
> 
> Bytemark Hosting
> http://www.bytemark.co.uk/
> tel. +44 (0) 845 004 3 004
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