Warning- Auto negotiation rant ahead.-
Auto negotiation was meant for the virtual
office where you do not know what type of Nic is being used by the end user.
But in environments where you typically know what type of NIC is being used you
should hard code the both the NIC and switch ports. A typical 100 meg NIC using
auto will get you about ~160 meg of measured bandwidth. If you hard code the
links you should be up in the 180-190 range. Same for gig links. Auto
negotiation with gig links will get you ~400-600 meg but when you hard code
where possible it should be up in the 800-900 range.
Pass this on to your management-
Speed
and duplex mode settings
Some vendor features like switch port
speed and duplex mode auto-negotiation can by themselves cause intermittent
network problems.
Most switch vendors support the auto-negotiate feature that is supposed to
allow the switch to determine the port settings based on what is optimum for
the NIC card. Auto-negotiation issues may result from non-conforming
implementation, hardware incapability, or software defects. When NICs or vendor
switches do not conform exactly to the IEEE specification 802.3u (100baseT, 802.3z
(1000Base-X), 802.3ab (1000Base-T) and GBIC, problems may result. Hardware
incompatibility and other issues may also exist as a result of vendor-specific
advanced features, such as auto-polarity or cabling integrity, that are not
described in the IEEE 802.3u/802.3z/ 802.3ab specifications for 100/1000 Mbps
auto-negotiation. Generally, if both the NIC and the switch adhere to the IEEE
802.3u/ 802.3z/ 802.3ab auto-negotiation specifications and all additional
features are disabled, auto-negotiation should properly negotiate speed and
duplex and no operational issues should exist. However, this rarely works as
the vendor claims, and in order to achieve maximum throughput it is best to
hard code these settings on the switch port and the NIC card.
Note: Some gigabit NIC drivers
such as those from Broadcom do not allow for hard coding the speed to 1000meg
therefore in this case you are left with using auto-negotiation to get the NIC
to run at gig speeds.
The speed is usually set to either 100 meg or 1000 meg (gigabit)
in today's networks. Again hard code both the speed and duplex mode for each
switch port and NIC to make sure both connections are set to the same. DO NOT hard code only one side of the
connection be it either just the NIC or switch port. This results in a duplex
miss-match in most all cases.
If duplex mode of these settings is mismatched, then no or very little data can
be transmitted and servers or client PCs will fail when they try to send data
through the network.
Flow control can hard coded also but if left to auto negotiate and
if it doesn’t link up correctly you should see a lot of input errors on
either the NIC or switch port.
Finally you may have to tune the NIC to the OS particularly with
GIG NICs being they have a higher demand on OS resources. You should engage
your system vendor for how to best tune the OS to the NICs.
Dan Otto
CCIE #2279
From:
veritas-bu-bounces AT mailman.eng.auburn DOT edu
[mailto:veritas-bu-bounces AT mailman.eng.auburn DOT edu] On Behalf Of Abhishek Dhingra1
Sent: Wednesday, January 16, 2008
8:05 AM
To: ckstehman AT pepco DOT com
Cc:
VERITAS-BU AT mailman.eng.auburn DOT edu; veritas-bu-bounces AT mailman.eng.auburn DOT edu
Subject: Re: [Veritas-bu] bpbkar:
ERR - bpbkar FATAL exit status =40: network connect
Can you help in getting the document which states that
NIC and switch setting should be 100 Mbps/1Gbps full duplex not auto
negaotiate, i am running the enivironment in which we have 1 Gbps LAN, NIC
and Switch is auto negotiate and most of the backup runs good, but few backups
has very less speed.
I
am unable to prove the auto negotiable thing to my management.
Abhishek Dhingra
IBM Global Services, Delhi,
Email : abhishek.dhingra AT in.ibm DOT com
Mobile :
+91-9818675370
ckstehman AT pepco DOT com
Sent
by: veritas-bu-bounces AT mailman.eng.auburn DOT edu
01/16/2008 07:12 PM
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To
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cc
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VERITAS-BU AT mailman.eng.auburn DOT edu,
veritas-bu-bounces AT mailman.eng.auburn DOT edu
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Subject
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Re: [Veritas-bu] bpbkar: ERR - bpbkar FATAL
exit status = 40: network connect
|
|
We have found this in most cases to be related to NIC settings being our of
sync.
Or related to firewall performance if the backup is coming through a firewall.
For 100MB both NIC and switch should be 100FDX no auto negotiate.
There are some regristry hacks to deal with the firewall issue.
=============================i
Carl Stehman
IT Distributed Services Team
Pepco Holdings, Inc.
202-331-6619
Pager 301-765-2703
ckstehman AT pepco DOT com
dgrabs03
<netbackup-forum AT backupcentral DOT com>
Sent by: veritas-bu-bounces AT mailman.eng.auburn DOT edu
01/16/2008 08:28 AM
Please
respond to
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Subject
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[Veritas-bu] bpbkar: ERR - bpbkar FATAL exit
status = 40: network connect
|
|
Hello there!
As I read the
/usr/openv/netbackup/logs/bpbkar/log.xxxx. The usual information I see is
04:27:05.852 [81170] <16> bpbkar: ERR -
bpbkar killed by SIGPIPE
04:27:05.882 [81170] <16> bpbkar: ERR -
bpbkar FATAL exit status = 40: network connection broken
04:27:05.886 [81170] <4> bpbkar: INF - EXIT
STATUS 40: network connection broken
I performed all the name resolution process from
nslookup up to the Netbackup tools "bpclntcmd" all are successful and
able to communicate to both client and the server/media. But the message above
frequently appears on the logs.
Is this a heavy network load issue?
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