Routing

Hi all,

I have a MX204 router that has it's SFP interfaces configured for 10G under chassis config. Now we have a use case where we need to configure a 1G link coming from our provider.

 From the documentation I know I can configure one of the SFP interfaces for 1G speed under chassis configuration so it can receive either UTP or optical 1G SFPs.

While reading the documentation I came across that speed can also be configured under a specific interface configuration. Would that indicate that I can have a 10G SFP interface but I can set the speed to 1G?

If that's the case would that mean that a 10G SFP would establish a link with the 1G interface on the provider side or would I still need to insert a 1G SFP for such a link?

Thanks for the help.

Hello,

I reviewed the docs (posted below) and the MX204 per the documentation doesn't allow for configuring 1GB under the chassis config, "You cannot configure 1-Gbps speed at PIC level and port level." You can configure a 10G interface to run at 1G speed but it will not establish a link with a 1G interface. A 1G optic/transceiver would be needed, which is supported per HCT.

References:

https://www.juniper.net/documentation/us/en/software/junos/interfaces-ethernet/topics/topic-map/port-speed-mx-routers.html

https://apps.juniper.net/hct/category/?catKey=100001&filters=speed%257C%257CGigabit%2520Ethernet%2526%2526productFamily%257C%257CMX%2520Series%2526%2526commonSKU%257C%257CNo&mType=product%20matrix

------------------------------
Paul Leszczynski

Original Message:
Sent: 12-21-2024 06:42
From: igor.hamzic81
Subject: MX204 configure 1G interface

Hi all,

I have a MX204 router that has it's SFP interfaces configured for 10G under chassis config. Now we have a use case where we need to configure a 1G link coming from our provider.

 From the documentation I know I can configure one of the SFP interfaces for 1G speed under chassis configuration so it can receive either UTP or optical 1G SFPs.

While reading the documentation I came across that speed can also be configured under a specific interface configuration. Would that indicate that I can have a 10G SFP interface but I can set the speed to 1G?

If that's the case would that mean that a 10G SFP would establish a link with the 1G interface on the provider side or would I still need to insert a 1G SFP for such a link?

Thanks for the help.

Hmm I'm not sure about those docs but I know for a fact that you can configure a 10G SFP on a MX204 to run in "1G" mode and connect to a remote 1G interface, as we are doing similar things on our end. You can even have a 40G fiber breakout into 10G operate at 1G speed if needed.

You would configure the port as a 10G port under the chassis config and then put the below statement under the interface config itself:

gigether-options {    auto-negotiation;    speed 1g;}

Your first link (Port Speed on MX Routers | Junos OS | Juniper Networks) states it as well in table 1: "Supports 1-Gbps speed on 10 Gigabit Ethernet ports (Junos OS Release 18.1 onwards)"

And just underneath it:
"When you choose an existing port speed configuration with an invalid port speed configuration, an alarm is generated indicating that the port speed configuration is invalid. You cannot configure 1-Gbps speed at PIC level and port level. But, you can configure the port configured at 10-Gbps speed to operate at 1-Gbps speed by using the speed statement. After you commit the configuration, the operating speed of the 10-Gbps port changes to 1-Gbps speed, but the show interface command displays the speed configuration (operating port speed) as 1GE."

Original Message:
Sent: 01-04-2025 13:00
From: Paul Leszczynski
Subject: MX204 configure 1G interface

Hello,

I reviewed the docs (posted below) and the MX204 per the documentation doesn't allow for configuring 1GB under the chassis config, "You cannot configure 1-Gbps speed at PIC level and port level." You can configure a 10G interface to run at 1G speed but it will not establish a link with a 1G interface. A 1G optic/transceiver would be needed, which is supported per HCT.

References:

https://www.juniper.net/documentation/us/en/software/junos/interfaces-ethernet/topics/topic-map/port-speed-mx-routers.html

https://apps.juniper.net/hct/category/?catKey=100001&filters=speed%257C%257CGigabit%2520Ethernet%2526%2526productFamily%257C%257CMX%2520Series%2526%2526commonSKU%257C%257CNo&mType=product%20matrix

------------------------------
Paul Leszczynski

Original Message:
Sent: 12-21-2024 06:42
From: igor.hamzic81
Subject: MX204 configure 1G interface

Hi all,

I have a MX204 router that has it's SFP interfaces configured for 10G under chassis config. Now we have a use case where we need to configure a 1G link coming from our provider.

 From the documentation I know I can configure one of the SFP interfaces for 1G speed under chassis configuration so it can receive either UTP or optical 1G SFPs.

While reading the documentation I came across that speed can also be configured under a specific interface configuration. Would that indicate that I can have a 10G SFP interface but I can set the speed to 1G?

If that's the case would that mean that a 10G SFP would establish a link with the 1G interface on the provider side or would I still need to insert a 1G SFP for such a link?

Thanks for the help.

Hello,

I reviewed the docs (posted below) and the MX204 per the documentation doesn't allow for configuring 1GB under the chassis config, "You cannot configure 1-Gbps speed at PIC level and port level." You can configure a 10G interface to run at 1G speed but it will not establish a link with a 1G interface. A 1G optic/transceiver would be needed, which is supported per HCT.

References:

https://www.juniper.net/documentation/us/en/software/junos/interfaces-ethernet/topics/topic-map/port-speed-mx-routers.html

https://apps.juniper.net/hct/category/?catKey=100001&filters=speed%257C%257CGigabit%2520Ethernet%2526%2526productFamily%257C%257CMX%2520Series%2526%2526commonSKU%257C%257CNo&mType=product%20matrix

Hi all,

I have a MX204 router that has it's SFP interfaces configured for 10G under chassis config. Now we have a use case where we need to configure a 1G link coming from our provider.

 From the documentation I know I can configure one of the SFP interfaces for 1G speed under chassis configuration so it can receive either UTP or optical 1G SFPs.

While reading the documentation I came across that speed can also be configured under a specific interface configuration. Would that indicate that I can have a 10G SFP interface but I can set the speed to 1G?

If that's the case would that mean that a 10G SFP would establish a link with the 1G interface on the provider side or would I still need to insert a 1G SFP for such a link?

Thanks for the help.