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Redundant Trunk Groups - Configuring

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  • 1.  Redundant Trunk Groups - Configuring

    Posted 08-13-2019 23:42


    Could someone tell me some RTG basics please, my Juniper reading appears to sugest to me that RTG is only configured at one end of the links (I am using ae x2 10Gb and minimum links 2) on back-to-back EX switches. STP is disabled, but even though testing proves that the links are redundant i.e. if a single 10Gb link fails. In normal working conditions all ports are seen as forwarding and not ae0 forwarding and ae1 blocking. I feel I have a fundamental misconception of RTG.

    Also can this work with Cisco Flex at one end and RTG ?

    Any guidence appreciated.

  • 2.  RE: Redundant Trunk Groups - Configuring
    Best Answer

    Posted 08-14-2019 00:14

    Hi Colin,


    Ideally RTG is used to replace STP between the access and distribution layers where one Access switch is connected to two different uplink switches and is Layer 2. If its back to back switches, RTG is not necessary and AE would solve the purpose.


    Yes, RTG is configured only one end which has two ports connecting to two different uplink switches. I see you are connecting two different AE interfaces between back to back switches with STP disabled. This will only cause a loop as per my understanding.


    RTG is very much similar to Cisco Flex. You configure RTG or Cisco Flex based on the setup.


    Please read through https://forums.juniper.net/t5/IOS-to-Junos-I2J-Tips/Flex-Links-vs-RTG/td-p/137169 for more understanding and also refer to the setup at https://www.juniper.net/documentation/en_US/junos/topics/topic-map/redundant-trunk-groups.html#id-example-configuring-redundant-trunk-links-for-faster-recovery-on-ex-series-switches


    Hope this helps.


    Please Mark My Solution Accepted if it Helped, Kudos are Appreciated too!!!

  • 3.  RE: Redundant Trunk Groups - Configuring

    Posted 08-14-2019 02:38

    Thank you Pradeep for the very quick response, will up date the results of our testing.

  • 4.  RE: Redundant Trunk Groups - Configuring

    Posted 08-14-2019 08:22

    As stated by @




  • 5.  RE: Redundant Trunk Groups - Configuring

    Posted 08-16-2019 11:18



    I appreciate your responses and thats where we are going to uses EX4300 to Nexus. As you say our testing has proven that useing EX43300 end with RTP ae interfaces 2 x 2, one LAG being is active and the other LAG is backup i.e. will not forward mac addresses. We did ae min links 2 and the the traffic moved from one to other LAG bundle.