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  • 1.  Connecting a Cisco SW and Juniper with access port

    Posted 06-06-2023 06:50
    Edited by spuluka 06-06-2023 18:57

    Hi Team,

    I am trying  to replace  our distribution SW - "Cisco WS-C3750G-24TS-1U"  with a Juniper EX34000

    I have moved all the links to the Juniper, but still 1 Link remaining that I can't make work from the Juniper

    How is currently Working: 

    ds1-sw-Cisco (WS-C3750G-24TS-1U)  link to  Customer's Cisco SW port 22

    We are only transporting layer two from this customer to our ds1-sw so We can provide layer 2 services to several devices connected in our Network. 

    ds1-sw-Cisco

    description link to Agg Sw for V140
     switchport access vlan 140
     switchport trunk encapsulation dot1q
     switchport trunk native vlan 140
     switchport trunk allowed vlan 101,140
     switchport mode access
     switchport nonegotiate
     no cdp enable
     spanning-tree bpdufilter enable

    Customer's Cisco SW port 22

    interface GigabitEthernet1/0/22
     switchport access vlan 101
     switchport mode trunk

    ds1-sw-Cisco to ds1-sw-Juniper

    interface GigabitEthernet2/0/1
     description temporal trunk to ds1-juniper
     switchport trunk encapsulation dot1q
     switchport trunk allowed vlan 10,101,140
     switchport mode trunk
     switchport nonegotiate
     no cdp enable

    ------------

    Issue when trying to remove ds1-sw-Cisco  and only use ds1-sw-Juniper :

    ds1-sw-Juniper  port 12 connected directly to customer's Cisco-sw on port 22  -->it doesn't work as soon as I change this I clear mac addresses in the SW for vlan 140 and 101.

    Juniper configuration 

      ge-0/0/12 {
            description " Agg Sw for V140";
            native-vlan-id 140;
            unit 0 {
                family ethernet-switching {
                    interface-mode trunk;
                    vlan {
                        members [ 101 140 ];
                    }
                    storm-control default;

    Hope someone can help me out here !

    Thanks



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    HECTOR OSSA
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  • 2.  RE: Connecting a Cisco SW and Juniper with access port

    Posted 06-06-2023 07:00

    The access port configuration looks correct and since it is untagged the vlan difference should not make a difference between the switches.

    Could you confirm there are not apply group configurations adding to the port by looking at inheritance.

    show configuration interfaces ge-0/0/12 | display inheritance 

    And confirm that ge-0/0/12 does not appear anywhere else in the vlan section of configuration

    show configuration vlans | match ge-0/0/12 | display set



    ------------------------------
    Steve Puluka BSEET - Juniper Ambassador
    IP Architect - DQE Communications Pittsburgh, PA (Metro Ethernet & ISP - Retired)
    http://puluka.com/home
    ------------------------------



  • 3.  RE: Connecting a Cisco SW and Juniper with access port

    Posted 06-06-2023 15:37

    Hi Spuluka, appreciate your time reviewing these!

    I just realised that I have been looking at this wrong.......   I got access to the customer SW, and the configuration on port 22 is actually like these:

    interface GigabitEthernet1/0/22
     switchport access vlan 101
     switchport mode trunk

    Allow me to type everything again.... 

    Current configuration that works from ds1-sw-Cisco to Customers SW

    Interface  gigabitEthernet1/0/19

    description PTP to Customers SW-Cisco V140
     switchport access vlan 140
     switchport trunk encapsulation dot1q
     switchport trunk native vlan 140
     switchport trunk allowed vlan 101,140
     switchport mode access
     switchport nonegotiate
     no cdp enable
     spanning-tree bpdufilter enable

    ds1-sw-Cisco to ds1-sw-Juniper 

    ------> Removing ds1-sw-Cisco   

    I tried with the configuration below, but it didn't work....  so far, what I see here is that We received from the customers vlan 101, and then We used vlan 140 to connect customers' devices from our Network infrastructure.

    do I need to do something like vlan rewrite? I am quite lost as I do not understand how it is being worked from the ds1.sw-Cisco...

     ds1-sw-Juniper to   Customer's Cisco SW 

    interfaces ge-0/0/12
    description "PTP to Customers SW-Cisco V140";
    native-vlan-id 140
    unit 0 {
        family ethernet-switching {
            interface-mode trunk;
            vlan {
                members [ 101 140 ];
            }
            storm-control default;

    -----Answering your questions 

    I confirm ge-0/0/12 does not appear anywhere else in the vlan section of the configuration

    user> show configuration vlans | match ge-0/0/12 | display set

    {master:0}



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    HECTOR OSSA
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  • 4.  RE: Connecting a Cisco SW and Juniper with access port

    Posted 06-07-2023 07:00

    If I remember my Cisco correctly vlan 140 is untagged / native on that side.

    Your Junos config has both vlans tagged so you need to add the command to make vlan 140 native.

           family ethernet-switching {
                port-mode trunk;
                native-vlan-id 140



    ------------------------------
    Steve Puluka BSEET - Juniper Ambassador
    IP Architect - DQE Communications Pittsburgh, PA (Metro Ethernet & ISP - Retired)
    http://puluka.com/home
    ------------------------------