[j-nsp] QSA adapters and MTU

[Richard McGovern]

Couple of things regarding this thread.

#1 – MX304 MTU: The MTU restriction ONLY applies when the QSA adapter is used with 1G Optic in an MX304. For 10G there is no MTU limitation. The reason being:

The 2K MTU limit is very specific to MX304. The MX304 uses the YT trio PFE, which does not have native support for a 1GE MAC. Workaround was to implement the 1GE in the PHY framer on the board, and this has a very shallow buffer – hence the MTU limit.

Advice is to take a simple EX as satellite and use that to aggregate 1G. No MTU restriction then.

#2 – MX204 1G speed. I thought MX204 interfaces were SFP+, which in Juniper terms equals 1/10 support. I thought the interface should auto-sense the installed optic to determine the speed. At the same time, for MX and SRX (but not EX/QFX) 1/10 SFP+ capable interfaces always use an interface naming designation as xe-. There is no support for ge- interface naming. This was an internal Juniper decision for ease of implementation, as original MX (and therefore SRX) interfaces were NOT SFP+ (1/10 support) originally. Instead they were SFP, which is 1G or 10G support, but not both. Both EX and QFX (and others) interfaces were SFP+ from day 1, due to time period they were built and the improved technology. To get 1G to work properly in a SFP+ interface, you may need to disable auto-neg on that interface. It really depends upon model/SW and I do not know all the combinations and details. If not working as expected, try this.

Hopefully this helps some and can clear up some things. I am just the messenger, . . .

FYI only, Rich

Richard McGovern
Sr Sales Engineer, Juniper Networks
978-618-3342

I’d rather be lucky than good, as I know I am not good
I don’t make the news, I just report it




Juniper Business Use Only

On 11/3/23, 2:53 PM, "Chris Adams" <cma at cmadams.net> wrote:
Once upon a time, Aaron1 via juniper-nsp <juniper-nsp at puck.nether.net<mailto:juniper-nsp at puck.nether.net>> said:
> I recall the MX204 being like that… an XE interface with a 1g speed command on the interface

There it's done under "interface xe-x/y/z gigether-options".  You set
"chassis fpc x pic y port z speed 10g" first, then speed 1g in the
interface.

--
Chris Adams <cma at cmadams.net<mailto:cma at cmadams.net>>