Switching

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Strange packet drops on EX4550 switch interface

  • 1.  Strange packet drops on EX4550 switch interface

    Posted 06-10-2021 05:33
    Hello good folks

    I have been observing packet drops on one of the switches, the setup is as

    [EX4550] ge-0/0/25--------------ge-0/1/2[EX2200]ge-0/0/47-------[Hypervisor]

    The drops are observed on port ge-0/0/25 of the EX4550, no drops on both involved ports of the EX2200.
    Utilization on the link between the switches is hardly over 200Mbps but according to Juniper's documentations

    Drops :
    Number of packets dropped by the input queue of the I/O Manager ASIC. If the interface is saturated, this number increments once for every packet that is dropped by the ASIC's RED mechanism

    Any ideas on where to look further?

    FYI The last I cleared below statistics was 24 hours ago and there are no any other errors except for drops in the output of show interface extensive so to avoid making the output long I filtered to match the keyword drops

    EX4550# run show interfaces ge-0/0/25 extensive | match "drops: [1-9]"
    Jun 10 09:27:47
    Carrier transitions: 0, Errors: 0, Drops: 2189555101, Collisions: 0, Aged packets: 0, FIFO errors: 0, HS link CRC errors: 0, MTU errors: 0, Resource errors: 0
    
    
    EX2200# run show interfaces ge-0/1/2 extensive | match drops    
    Jun 10 12:28:54
        Errors: 0, Drops: 0, Framing errors: 0, Runts: 0, Policed discards: 0, L3 incompletes: 0, L2 channel errors: 0, L2 mismatch timeouts: 0, FIFO errors: 0, Resource errors: 0
        Carrier transitions: 1, Errors: 0, Drops: 0, Collisions: 0, Aged packets: 0, FIFO errors: 0, HS link CRC errors: 0, MTU errors: 0, Resource errors: 0
    
    
    [edit]
    EX2200# run show interfaces ge-0/0/47 extensive | match drops             
    Jun 10 12:29:06
        Errors: 0, Drops: 0, Framing errors: 0, Runts: 0, Policed discards: 0, L3 incompletes: 0, L2 channel errors: 0, L2 mismatch timeouts: 0, FIFO errors: 0, Resource errors: 0
        Carrier transitions: 1, Errors: 0, Drops: 0, Collisions: 0, Aged packets: 0, FIFO errors: 0, HS link CRC errors: 0, MTU errors: 0, Resource errors: 0
    
    


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    Paul Basondole
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  • 2.  RE: Strange packet drops on EX4550 switch interface

     
    Posted 06-10-2021 05:57
    Do you have any Class of service configured on the switch?  Some errors in that might cause this issue.

    Also confirm the interface is successfully full duplex
     show interfaces ge-0/0/25 media

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