Connection down

Publication Date:  2016-08-30 Views:  429 Downloads:  0
Issue Description

Lets assume that you have one NE20E connected to a S5720.

Configuration for NE:

interface GigabitEthernet0/0/0
 speed 1000
 duplex full
 undo shutdown
 ip address 10.1.63.3 255.255.255.240

Configudation for S5720:

interface GigabitEthernet0/0/47
 undo negotiation auto
 port link-type access
 port default vlan 248

If we check the port G0/0/0 we can see it is UP.

GigabitEthernet0/0/0 current state : UP (ifindex: 3)
Line protocol current state : UP
Last line protocol up time : 2016-08-15 13:45:49+01:00
Link quality grade : GOOD
Description: MGMT-SECONDARY
Route Port,The Maximum Transmit Unit is 1500
Internet Address is 10.1.63.3/28
IP Sending Frames' Format is PKTFMT_ETHNT_2, Hardware address is 20f1-7ce7-2ca0
Media type: twisted-pair, link type: negotiation disable
loopback: none, promiscuous: off
maximal BW: 1000M, current BW: 1G, full-duplex mode

 

But on the switch, the interface is down.

 

GigabitEthernet0/0/47 current state : DOWN
Line protocol current state : DOWN
Description:UK-CR1B
Switch Port, Link-type : access(configured),
PVID :  248, TPID : 8100(Hex), The Maximum Frame Length is 9216
IP Sending Frames' Format is PKTFMT_ETHNT_2, Hardware address is e4a8-b663-e080
Current system time: 2016-08-25 11:25:33
Port Mode: COMMON COPPER
Speed : 1000,   Loopback: NONE
Duplex: FULL,   Negotiation: DISABLE
Mdi   : AUTO,   Flow-control: DISABLE

 

If we enable auto-negotiation, the port negotiates as 100 Mb Half duplex.

Solution

The solution is to set both ports with the same speed, duplex, and negotiation. As below.

NE20E:

interface GigabitEthernet0/0/0
 speed 1000
    
 duplex full
 undo shutdown
 ip address 10.1.63.3 255.255.255.240

 

S5720:

interface GigabitEthernet0/0/47

 speed 1000    
 duplex full
 port link-type access
 port default vlan 248

END