Hi,
On 06.05.2020 18:03, Chris Wopat wrote:
On Wed, May 6, 2020 at 9:41 AM Brian Johnson <brian.john...@netgeek.us> wrote:
So you have a 4x10G breakout and a 100G QSFP28 in the same group of 3
interfaces and they are all working? Just because I can install and configure
the optics, doesn’t mean they will function. This would conflict with what is
coming from Juniper Product teams.
To be clear, I realize that the ports do not “disappear” because you insert the
QSP28 into the port group, just that they will not work. :)
We've been this with MPC7s, works fine. You can squeeze the 240g out
of each PIC just fine, you simply cannot oversub.
fpc 7 {
pic 0 {
port 2 {
speed 100g;
}
port 4 {
speed 10g;
}
port 5 {
speed 100g;
}
}
}
ports 4 and 5 in same 'group of 3', et-7/05 up at 100g and
xe-7/0/4:[0-3] up at 10g.
I always wondered whether there is an explicit knob to disable a port in order
to prevent accidental wrong configs or transceivers inserts down the road. Of
course you can annotate the existing ports or the pic, but besides that. Also
what happens if somebody plugs in a transceiver into any of the remaining
ports? Will the setup just fall apart?
You have 6 Ports per PFE and if you do 100GE on two of them you will end up with
something similar to the above config (you can choose whether to do 40 or 10GE on one of
the ports). Which leaves three interfaces unconfigured or not listed in the config. In
fact whenever one port is configured to 100G you will "loose" at least one of
the ports and have to leave it not listed in config for things to work.
If at some point in the future somebody configures any of the remaining ports
for an invalid speed it will not work. Even worse default mode for MPC7E-MRATE
is to fallback to 10GE Mode on all ports on invalid config which could kill
your 100GE production ports. Luckily you have to bounce the PFE for speed
changes, which could be even worse if your wrong config hits you during your
next reboot if you do not mind the alarms ;)
"If rate selectability is not configured or if invalid port speeds are configured,
each port operates as four 10-Gigabit Ethernet interface"
"When you change an existing port speed configuration at the port level, you must
reset the MPC7E-MRATE PIC for the configuration to take effect. An alarm is generated
indicating the change in port speed configuration."
https://www.juniper.net/documentation/en_US/junos/topics/topic-map/rate-selectability-configuring.html
So it would be great to have a config option to explicitly disable specific
ports and not just leave them unconfigured. Of course you can also misconfigure
any of the disabled ports into a unsupported speed combo, but it would be a bit
more visible that they are disabled by intention.
You probably could configure all ports and literally "deactivate" the configs
that you do not want to be enabled and annotate that, but it feels a bit clunky.
Especially on boxes like MX204 and MX10003 we would always explicitly configure
the ports into a valid config combination to prevent somebody from putting in
transceivers and the box trying to be smart and mess up your ports. I think you
cannot easily do that on the MPC7
--
Kind Regards
Tobias Heister
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