I think you meant an *M40e* chassis.
The main point to the M40e is the redundant control and forwarding
capabilities that you mention. As the M40 had neither, this is a
significant improvement. This is not to say that the M40 is broken.
Redundancy is an insurance policy. Whether you feel the premiums is
worth the peace of mind is a matter of personal choice.
My understanding is that M40s were often deployed in pairs to achieve
redundancy. A single M40e has to be a better solution, and the M40 is
now EOL anyway. I believe that an M40e can be bought w/o redundant RE
and SFM.
I think that MTBF numbers are posted at the public website. Check out
the edit snip below. Now that is a reliable box!
[clip]
> bla@xxxxx> show system uptime
> Current time: 2003-09-18 19:06:29 UTC
> System booted: 2001-09-10 18:30:05 UTC (105w3d 00:36 ago)
> Protocols started: 2001-09-10 18:29:08 UTC (105w3d 00:37 ago)
> Last configured: 2003-09-18 06:13:40 UTC (12:52:49 ago)
> 7:06PM up 738 days, 36 mins, 1 user, load averages: 0.02, 0.03, 0.00
^^^^^^
>
> bla@xxxxx> show version brief
> Hostname: XXXXX
> Model: m40 <<<<<
> JUNOS base [4.2R3]
> JUNOS Kernel Software Suite [4.2-20010502-ot7565]
> JUNOS Routing Software Suite [4.2-20010502-ot7565]
> JUNOS Packet Forwarding Engine Support [4.2-20010502-ot7565] JUNOS
> Online Documentation Files [4.2-20010502-ot7565]
HTHs.
> -----Original Message-----
> From: juniper-nsp-bounces@puck.nether.net
> [mailto:juniper-nsp-bounces@puck.nether.net] On Behalf Of joe mcguckin
> Sent: Wednesday, September 24, 2003 3:21 PM
> To: juniper-nsp@puck.nether.net
> Subject: [j-nsp] Reliability of M20 chassis ?
>
>
> I notice that Juniper came out with the M20e chassis which
> can accept a redundant route engine and switch fabric board.
>
> Has this been a real problem that required a fix? Or is this
> a feature that rarely is used, but makes owners feel more secure?
>
> There must still be a lot of original M40's out there. Are
> they running ok or are carriers replacing them with M40e's ?
>
> Thanks,
>
> Joe
>
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