[j-nsp] EX4100/EX4400 1GE autoneg issues on SFP+ ports

[Crist Clark]

https://www.juniper.net/documentation/us/en/software/junos/cli-reference/topics/ref/statement/auto-negotiation-edit-interfaces.html

NOTE: 1G optical transceivers do not support auto-negotiation on EX4100
1G/10G uplink module (PIC 1/PIC 2) and EX4400 1G/10G interface. 1G-T
supports auto-negotiation on these ports.


On Sun, Nov 10, 2024 at 1:16 PM Bernhard Schmidt via juniper-nsp <
juniper-nsp at puck.nether.net> wrote:

> Hey,
>
> maybe someone has a quick idea before I pester JTAC for weeks without
> success.
>
> We are starting to migrate our campus network to Juniper EX4100/EX4400
> series and we have hit a blocker. We've now had several cases where we
> could not get a working 1GE fiber connection when the Juniper side was
> in a SFP+ slot
>
> First issue with a EX4100-F-12P with an original JNPR 1GE-LX optics in
> ge-0/1/0, the other side being an unmanaged media converter. Running
> 22.4R3.25
>
> Second issue was a EX4400-48F with a third-party 1GE-SR optics in
> ge-0/0/36+, the other side being a Huawei S5720 switch. Running
> 23.4R1.9.
>
> In both cases the behaviour is the same
>
> - JNPR sees link-up, no incoming packets
> - the other side sees the link as down, but has a decent Rx power
>
> We know of these 1GE fiber autoneg issues from our Arista core (where,
> according to Arista, there is just no 25G chip available on the market
> that can do 1GE with auto-neg), so we have to disable 1GE autonegotation
> on the other side in the few cases this is happening. But this is
> campus, so we don't have control over the other side, and it even
> happened with unmanaged converters.
>
> I think it's the autoneg issue because when I add "undo negotiation auto"
> on the Huawei side the link comes up there as well, and we can pass
> traffic just fine. However, that's not an option in Campus, see above.
>
> Also, moving the link from port 36 (1G/10G) to port 35 (1G only) on the
> EX4400-48F fixes the issue as well.
>
> I have tried (on the EX4100-F)
>
> set interfaces ge-0/1/0 ether-options auto-negotiation
>
> and optionally
>
> set interfaces ge-0/1/0 speed auto
>
> according to
>
> | Autonegotiation is enabled by default, and will autonegotiate the
> | speed with the link partner. We recommend that you keep autonegotiation
> | enabled for interfaces operating at 100M and 1G. By default,
> | autonegotiation is disabled on 10-Gigabit fiber ports.
>
> | If for some reason you have disabled autonegotiation, you can enable it
> | by issuing the set interfaces name ether-options auto-negotiate command.
>
> | To disable autonegotiation, issue the delete interfaces name
> | ether-options auto-negotiate command.
>
> to no avail.
>
> Does anyone have any idea how I can beat the Juniper side into doing
> autoneg on 1GE fiber?
>
> Bernhard
>
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