Etherchannel Jumbo Frames and UDP

[jprabaker]

Hello,

I've configured an etherchannel on my NIM Server using jumbo frames, setting the mtu on the interface to be 9000. Now I can't do NIM installs, I get an error when the system tries to get the bootfile:

ERROR: icmp 3
icmp 3 : port unreachable
ERROR: icmp 3
icmp 3 : port unreachable
ERROR: icmp 3
icmp 3 : port unreachable
BOOTP: read-first-block fail: 0


My "no" udp parameters as set as so:

udp_bad_port_limit = 0
udp_ephemeral_high = 65535
udp_ephemeral_low = 32768
udp_inpcb_hashtab_siz = 24499
udp_pmtu_discover = 1
udp_recvspace = 655360
udp_sendspace = 655360
udp_ttl = 30
udpcksum = 1


Anyone know how to fix this?


Thanks in advance,
John

 

[kHz]

Does your switch support jumbo frames?

You don't mention your version of AIX, but for 5.2 you have to enable jumbo frames on the adapter before creating the etherchannel.

In 5.3, jumbo frames are automatically enabled for every adapter when the enable jumbo frames value is yes.

You should also increase your tcp_sendspace and tcp_recvspace and set rfc1323 to 1.

 

[jprabaker]

Were are running 5300-05-04. Jumbo frames are supported over etherchannel on our switches. tcp settings are:

tcp_recvspace = 262144
tcp_sendspace = 262144
rfc1323 = 1

 

[p5wizard]

On install, the ethernet adapters probably revert to non-jumboframe mode. So I fear it's a no-can-do...

or is there jumbo frame support in the SMS menus?


HTH,

p5wizard

 

[jprabaker]

Hmm, well I've got my install working over NIM (reverse lookup issues I think..), but now I've found I've got NFS issues along with other problems. I can mount a filesystem from by NIM server, but it takes around 10 seconds to mount. When mounted I can't do an ls within the nfs mounted filesystem.

I've had to revert back to default mtu and jumbo frame settings to get things working again.

Is it possible that something else needs to be set on the switches?


Thanks,
John

 

[mrn]

You've got to be using 1000 MBps full duplex to be able to use Jumbo frames.

Mike

"Whenever I dwell for any length of time on my own shortcomings, they gradually begin to seem mild, harmless, rather engaging little things, not at all like the staring defects in other people's characters."