Visit Our UNIX and Linux User Community

Connected and Running with half duplex speed

Thread Tools Search this Thread
Operating Systems AIX Connected and Running with half duplex speed
# 1  
Old 07-27-2012
Connected and Running with half duplex speed

VIO Server connected to switch port and running with half duplex speed on one of the shared ethernet adapter. We have verified at switch end and everythings looks good.
Other ethernet adapter in the VIO server are connected and running in Full duplex speed.

Please help me find why this shared ethernet adapter is having half duplex speed and how to fix this back to full duplex.

Sometime back it was running as full duplex and recently there were no changes/upgrades on both switch and VIO server level.

$ ioslevel
# lsdev -Cc adapter | grep -i ent14
ent14    Available       Shared Ethernet Adapter
# entstat -d ent14 | grep -i media
Media Speed Selected: Auto negotiation
Media Speed Running: 10 Mbps Half Duplex
# lsattr -El ent14 | grep -i real
real_adapter  ent4     Physical adapter associated with the SEA                           True

- Mugunth
# 2  
Old 07-27-2012
Proper fix is to get rid of "Auto negotiation" at both the Server and the Switch Port and positively set the line speed. Then cold start the Switch and then the Computer.

This problem arises from re-plugging network ports with the power on. Very bad practice. The same net-effect happens by power-cycling the Switch.

The quick fix is to power-down the server, power-cycle the Switch, power-up the server. In that strict order.
This User Gave Thanks to methyl For This Post:
# 3  
Old 08-03-2012
Also, check to see if you have the latest microcode on your card. Sometimes when we get replacement hardware, the microcode is way behind. I can't think of a good reason to not be on the latest microcode level released by IBM.
# 4  
Old 08-03-2012
Originally Posted by methyl
This problem arises from re-plugging network ports with the power on. Very bad practice. The same net-effect happens by power-cycling the Switch.
Why is this bad practice? Negotiation can happen at any time, yes?
# 5  
Old 08-04-2012
Originally Posted by Corona688
Why is this bad practice? Negotiation can happen at any time, yes?
I have no opinion about this being bad practice or not - IMHO you are right and negotiation can happen at any time. On the other hand, since the times of the 10/100-Adapters Auto Negotiation in IBM Adapters has created far more problems than it solved (if it solved any, that is). I.e. CISCO Switches were for a long time famous for not being able to cope with IBMs adapters in Auto-Negotiation mode and consistently one ended with a port set to 100-Full and a NIC set to 100-Half Duplex (resulting in a bandwidth of ~1kbit/min).

In my experience switching off Auto Negotiation first thing a connection problem arised solved an awful lot of cases - even ones where Auto Negotiation worked for some time, because every microcode update or firmware upgrade might introduce this damn incompatibility again even if it was already solved.

I hope this helps.

These 2 Users Gave Thanks to bakunin For This Post:

Previous Thread | Next Thread
Test Your Knowledge in Computers #515
Difficulty: Easy
A variable's type (or data type) is the characterization of the data that it represents.
True or False?

8 More Discussions You Might Find Interesting

1. SCO

System Clock running at half speed

SCO Openserver 6.0.0 had an issue with a NIC losing it's config on reboot. Netconfig would not allow "view protocol" and apparently zeroed out the existing IP info. Repaired from console. After this event, however, the system clock seems to lose 30 seconds for every RTC minute that passes. As a... (1 Reply)
Discussion started by: DoublePanic
1 Replies

2. Linux

Network 10Mb/s half duplex only. r8168 on Centos 5.

Hi, For some reason my network card started going 10Mb/s half duplex instead of 1000Mb/s full duplex. System is connected to 8x1Gb HP switch. Other devices connect fine through the switch and get full 1Gb network. I have Centos 5 with all updates. Driver comes from elrepo and as well is... (1 Reply)
Discussion started by: columb
1 Replies

3. AIX

How to change Speed Duplex

How to change Speed Duplex ! How to change Speed Duplex by command chdev -P -l ent1 -a media_speed=1000_Full_Duplex How to change Speed Duplex by Smitty . smitty chgenet -> select adapter -> change Media speed etc. -> set "Apply change to DATABASE only" to yes -> Enter -> ... (0 Replies)
Discussion started by: ITHelper
0 Replies

4. Solaris

How to find half duplex or full duplex

Hi, How to find whether the server is running with half duplex or full duplex. I tried with the following command ndd -get /dev/ but am not getting any output,. Is the command correct? Also let me know how to change from half to full duplex. (1 Reply)
Discussion started by: rogerben
1 Replies

5. Solaris

Solaris 10 Speed and Duplex Settings: bge

Evening, I am attempting to change the speed and duplex settings on a single interface on a bge card on an m3000 SPARC server. Currently the settings are as follows: bge0 link: up speed: 1000 Mbps duplex: full bge1 link: up speed: 100 Mbps ... (13 Replies)
Discussion started by: brialt1
13 Replies

6. Infrastructure Monitoring

How to find the duplex speed on Windows

Hi, In UNIX, it's very easy to find the duplex speed. But in Windows, is there a easy way to find the duplex speed? I can't go to over 100 servers to find this out, I was wondering if I run one command to do this? Please advice. (2 Replies)
Discussion started by: samnyc
2 Replies

7. Solaris

gigabit - fix speed/duplex on the switch ? or autoneg ?

Hi there We have a bit of a debate going here over what the prefered method is for setting 1000/Full on e1000g or nge interfaces is. As you aware the Solaris configration files for nge and e1000g dont allow you to "fix" 1000/Full but instead allow you to set auto-negotiate to ON but only... (1 Reply)
Discussion started by: hcclnoodles
1 Replies

8. IP Networking

NIC speed 100M/full duplex problem

I have a TOSHIBA AS7000 B150 Sun Box I wanted to run it with 100M/full duplex I had added this to the /etc/system file to make to setting permenant So it would be set correctly on reboot. set eri:eri_adv_100fdx_cap=1 set eri:eri_adv_100hdx_cap=0 set eri:eri_adv_autoneg_cap=0 But when I... (4 Replies)
Discussion started by: AirWalker83
4 Replies

Featured Tech Videos