09-01-2010 09:06 PM
I'm quite new to the switch thing.
I have configured Jumbo frame on the NIC with command ifconfig eth0 mtu 9000 on the linux server side.
Now I need to know how to configure Jumbo Frame on the switch. should I also set mtu to 9000 on the switch or a larger value? can I only set mtu for every port I connect or need to change global mtu? and How to configure that.
Thanks in advance.
09-02-2010 12:37 AM
Yes you need to set the MTU to the same value on ALL lan port in the same vlan. I do not know the Brocade 8000 FCoE switch, looking for the manual now.
Haveever most switches let you set the MTU on a global, vlan or port level.
09-02-2010 12:55 AM
Thank you anyway.
actually, I also dobut that if 9000 the correct mtu size to set on the switch? as last time, with DELL switch, the support people told me that I need to set it to 9216 to enable jumbo frame on the switch...
09-02-2010 01:02 AM
9K is the value used most commonly for jumbo frames, however this is express as 1024 byte * 9 = 9216 - that is where the value get a little confiussed.
Standard enternet frames are 1514 bytes, so anthing over that is a jumbo setting. Some vendors support a maximum setting for MTU to 9216. some set it as 9000. You need to find the setting that all devices can aggree on.
09-02-2010 01:58 AM
I have found below commands may refer to, but still have a question:
HBA_8000_19(config)#int te 0/0
0/0 port is not some special port, by changing mtu on this port, it doesn't affect other ports on the switch, right? If my server is not connected to the 0/0 port, I need to use different port number, right? in my case, I have 4 servers connected to the switch, so I should run the commands for 4 different ports, right?
do I need to restart the switch to make the change effective right away? for DELL switch, I need to run the command "reload", how about Brocade switch?
Configuring the MTU on an interface
By default, all 10G Ethernet interfaces use a default MTU of 2500. In this step, we will set the
MTU to 1522.
1. At the FOS CLI, switch to the CEE CLI using the “cmsh” command, then do the
Enter configuration commands, one per line. End with CNTL/Z.
HBA_8000_19(config)#int te 0/0
<1522-9208> MTU in bytes
2. To confirm the change run:
HBA_8000_19(conf-if-te-0/0)#do sh run int te 0/0
interface TenGigabitEthernet 0/0
3. Write the configuration to memory
Overwrite the startup config file (y/n): y
09-02-2010 02:29 AM
Hi Betty, the quick answer (and the one you do not want to here) is, I do not know.
I really do need to have a read of the manual for the 8000 switch - and I cannot find one. (have posted another question on where to get that manual).
However, my guess would be;
These command look more Cisco then Foundry/Brocade so;
0/0 is the first port on the switch. So you would enter the command on each interface that the 4 servers are connected to.
try doing a ' do show interface bri' to list all the ports while at the config term level. This should show you the port numbers and MAC addresses.
As the siwtch from your post lists the default MTU as 2500 - there is a good chance that a reload is not required - but again I would neeed the manual to be sure.
Doing a 'do show interface 0/x' - where x is the port number that one of the switches is connected should show you MTU setting - so if after changing to 9000 it is not listed then try a reload.
Note if you are using Brocade CNA's in ALL your servers then go with the max MTU setting of 9208 as this should work. However is using other vendors then stay at 9000 this is the defacto standard.
Thanks. P.S. if you have the manual there - please post and I will look at it for you.
09-02-2010 02:41 AM
09-02-2010 02:59 AM
Yep both are helpfull.
MTU can only be set on an interface level on this switch (or at lest in that rev of code).
A reload is not required.
This is not clear but : Ports are numbered from 0/1 to 0/24 OR 0/0 to 0/23
So the above information I gave is correct. Hope all work well for you tmorrow.