Cisco ISR 4451 - Interface setting

[RS19]

I have Cisco ISR 4451. I has interface Gi0/0/0
I want to set the port to 1000/full.

Is the below command command sufficient ?

interface GigabitEthernet0/0/0
speed 1000
no negotiation auto

Or should i also need to add "duplex full"

Let me know.

[Joseph W. Doherty]

Not 100% positive with gig Ethernet, but w/o duplex full, and w/o auto, believe you'll get 1000/half.

BTW, why do you want to hard code 1000/full?  Since the beginning of this century, hardware vendors recommend auto/auto.

[RS19]

cause it is connected to ISP ONU & it is the recommendation from the ISP

[Joseph W. Doherty]

ISP hard coded full duplex "recommendation"?!  Are you sure it's not a requirement?

Reason I ask, normally both sides should be configured alike.  An auto<>full will end up as half<>full.  I.e. if ISP is using full, then your side should be using full.

Working with an ISP, unsurprising they are still using a last century practice.

[RS19]

any inputs ?

[MHM Cisco World]

If ISP router is from other vendor and don't use autonego then  disable autonego and hardcoded the speed and duplex 

Speed xxxx

Duplex full

MHM

[Giuseppe Larosa]

Hello @RS19 ,

it is better to not leave any doubt so when going manual use commands to set both speed and duplex

int gi0/0/0

speed 1000

duplex full

only in this way you can be sure it will be 1000 Mbps full duplex

Hope to help

Giuseppe

[paul driver]

Hello
My understanding full gig ports are full duplex by default, this cannot be change, only 10/100/1000 ports have that capability

[RS19]

u mentioned 10/100/1000 ports. 1000 means 1 G right . Is my understanding right.

[paul driver]

Hello
EDITED:-- should state ive found this to be applicable on certain platforms.

I mean ports that can be either be 10/100/1000 have the capabiltiy to be duplex set, true 1GB + ports are full duplex by default and dont have the capability to have duplex hardcoded on certain plaforms at least

[Joseph W. Doherty]

I recall (???) even for copper, gig doesn't allow for half duplex, i.e. possibly it's non-standard, but platforms may permit it for 3x speed ports, where half is a standard for 10 and 100.  This might explain the difference @paul driver notes he has observed for 3x vs. gig only ports.

[MHM Cisco World]

Yes correct 

10/100/1000 is for mbytes

1000 mbytes is equal to 1gbytes

MHM

[paul driver]

Hello
This post has got me thinking,
im aware on some platform you can specify the media or disable negotiation, so the speed/duplex are then viable. However surely others on this forum have also come across 1Gb + ports that you cannot hardcode the duplex?

I definitely have but I just cannot remember what platforms and software it was on?

[MHM Cisco World]

You are correct some 1 G can not hardcoded it duplex 

But let wait his try to config both speed and duplex