Devices are connected to ports et-0/0/4-7 of the router with different IP's on the same subnet and MNGT vlan 201.

But only the first device connected becomes reachable via ICMP (ping); the others are unreachable despite being configured identically. What could be the cause.

Kindly assist with identifying why only one device on VLAN 201 is reachable at a time, despite all being configured identically and on separate physical interfaces.

root@JTAC> show arp

MAC Address      Address        Name                     Interface              Flags

aa:bb:cc:dd:ee:ff a.b.c.d     a.b.c.d               irb.201[ et-0/0/7.201 ] none

Total entries: 1

root@JTAC> show ethernet-switching table

<snip>

Ethernet switching table : 1 entries, 1 learned

Routing instance : default-switch

   Vlan               MAC                MAC        Age  GBP    Logical               NH       MAC       RTR

   name               address            flags            Tag    interface             Index    property  ID

   VLAN201            aa:bb:cc:dd:ee:ff  D            -          et-0/0/7.201          0                   0

We tested in lab, with same config/version/device & wer not seeing the issue.

Lab:

+++++++++++++++

root@JTAC> show arp   

MAC Address    Address     Name           Interface        Flags

aa:bb:cc:dd:ee:18 a.b.c.11   a.b.c.11        irb.201[ et-0/0/3.201 ] none

aa:bb:cc:dd:ee:20 a.b.c.12   a.b.c.12        irb.201[ et-0/0/4.201 ] none

aa:bb:cc:dd:ee:28 a.b.c.13   a.b.c.13        irb.201[ et-0/0/5.201 ] none

aa:bb:cc:dd:ee:30 a.b.c.14   a.b.c.14        irb.201[ et-0/0/6.201 ] none

Total entries: 4

| 

root@JTAC> show ethernet-switching table   

<snip>

Ethernet switching table : 4 entries, 4 learned

Routing instance : default-switch

  Vlan        MAC         MAC     Age  GBP   Logical        NH    MAC    RTR

  name        address       flags       Tag   interface       Index   property  ID

  VLAN201       aa:bb:cc:dd:ee:18  D       -      et-0/0/3.201      0          0    

  VLAN201       aa:bb:cc:dd:ee:20  D       -      et-0/0/4.201      0          0    

  VLAN201       aa:bb:cc:dd:ee:28  D       -      et-0/0/5.201      0          0    

  VLAN201       aa:bb:cc:dd:ee:30  D       -      et-0/0/6.201      0          0  

+++++++++++++++

Upon checking this in live:

> Cusotmer was using all Non-Juniper SFPs (one Finisar & other 3 were tunable ones)

> The mac is only learned on et-0/0/7, with Finisar SFP (a.b.c.2 arp)

> When other cables are moved to this, the other MACs are learned

> We swapped the SFP+cable between et-0/0/4 & 7

> We saw the MAC now learned via et-0/0/4

> We then moved the cable between them, without changing SFP

> Now we could see arp for a.b.c.5 on et-0/0/4, which means it could be SFP issue

Customer swapped the tunable SFPs with Finisar ones & issue was resolved.

They can use below link to validate if any SFP is supported by Juniper on any given platform.

https://apps.juniper.net/hct/product/