Whether the Speed Auto can have a network speed reach to the switchport top?

My Juniper EX4300 Switch ge-0/0/42 switchport configuration is bellow:

admin@1409A# run show interfaces ge-0/0/42                                      
Physical interface: ge-0/0/42, Enabled, Physical link is Up                     
  Interface index: 689, SNMP ifIndex: 590                                       
  Link-level type: Ethernet, MTU: 1514, MRU: 0, Link-mode: Full-duplex,         
  Speed: Auto, BPDU Error: None, MAC-REWRITE Error: None, Loopback: Disabled,   
  Source filtering: Disabled, Flow control: Enabled, Auto-negotiation: Enabled, 
  Remote fault: Online, Media type: Copper,                                     
  IEEE 802.3az Energy Efficient Ethernet: Disabled                              
  Device flags   : Present Running                                              
  Interface flags: SNMP-Traps Internal: 0x0                                     
  Link flags     : None                                                         
  CoS queues     : 12 supported, 12 maximum usable queues                       
  Current address: 88:a2:5e:5c:69:8d, Hardware address: 88:a2:5e:5c:69:8d       
  Last flapped   : 2018-11-15 18:30:19 UTC (6d 16:28 ago)                       
  Input rate     : 627968 bps (619 pps)                                         
  Output rate    : 666800 bps (638 pps)                                         
  Active alarms  : None                                                         
  Active defects : None                                                         
  Interface transmit statistics: Disabled                                       

  Logical interface ge-0/0/42.0 (Index 599) (SNMP ifIndex 595)                  
    Flags: Up SNMP-Traps 0x0 Encapsulation: Ethernet-Bridge                     
    Input packets : 4                                                           
    Output packets: 0   

You see the Speed is Speed: Auto.

My question is whether the Server who connected to this switchport can have a very high speed to 1Gpbs without limit?


The ge part of the interface name indicates a gigabit port. So, as long as auto negotiation is enabled and the facing port supports gigabit as well (and the cable is at least Cat-5e, of course), they will connect at gigabit speed.

Auto negotiation is mandatory for (twisted-pair) Gigabit Ethernet, so you should never configure a port to a specific speed or duplex mode unless very specific reasons force you to do so.

Source : Link , Question Author : three-blocks , Answer Author : Zac67

Leave a Comment