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2848 not forwarding jumbo frames

Marc 'Zugschlus' Haber
Occasional Contributor

2848 not forwarding jumbo frames

Hallo,

I have a ProCurve 2848 with Softtware I10.77. Port 24 and Port 36 each have a Linux system connected. Both ports are up with 1000FDx (verified with show int brief) and are configured for VLAN 102 "untagged". VLAN 102 is jumbo-frames enabled, this is visible in show vlans.

The Linux boxes have MTU 9000 configured.

When I ping with "large" (ping -s 1479 ) packets, the other side does not see the ICMP echo request packet coming in. The switch loggs the Packet under "Total Rx Errors", but not in the more exact error categories - especially not under "Giants".

| Status and Counters - Port Counters for port 36
|
| Name :
| Link Status : Up
| Totals (Since boot or last clear) :
| Bytes Rx : 1588 Bytes Tx : 36,234
| Unicast Rx : 1 Unicast Tx : 1
| Bcast/Mcast Rx : 0 Bcast/Mcast Tx : 232
| Errors (Since boot or last clear) :
| FCS Rx : 0 Drops Rx : 0
| Alignment Rx : 0 Collisions Tx : 0
| Runts Rx : 0 Late Colln Tx : 0
| Giants Rx : 0 Excessive Colln : 0
| Total Rx Errors : 1 Deferred Tx : 0
| Rates (5 minute weighted average) :
| Total Rx (bps) : 594704 Total Tx (bps) : 5000832
| Unicast Rx (Pkts/sec) : 0 Unicast Tx (Pkts/sec) : 0
| B/Mcast Rx (Pkts/sec) : 0 B/Mcast Tx (Pkts/sec) : 0
| Utilization Rx : 00.05 % Utilization Tx : 00.50 %

What's the fault? Are jumbo frames supported for untagged VLANs? Do I need to reboot the switch before jumbo frames are forwarded?

Greetings
Marc
1 REPLY
Paulen
Regular Advisor

Re: 2848 not forwarding jumbo frames

Hi,

We are running an MPLS link through a 3400 - and it works like a charm. However, before we upgraded to the current version (M.10.68), we only got jumbo frames in one direction(!). Go figure..

I only have an untagged VLAN on both sides of the switch. This is how it looks like on my interface:

Name : My interface
Link Status : Up
Totals (Since boot or last clear) :
Bytes Rx : 987,253,458 Bytes Tx : 972,372,936
Unicast Rx : 2,752,720,702 Unicast Tx : 4,018,739,463
Bcast/Mcast Rx : 10,966,561 Bcast/Mcast Tx : 14,391,832
Errors (Since boot or last clear) :
FCS Rx : 156 Drops Rx : 0
Alignment Rx : 0 Collisions Tx : 0
Runts Rx : 0 Late Colln Tx : 0
Giants Rx : 2,687,830,911 Excessive Colln : 0
Total Rx Errors : 225 Deferred Tx : 0
Rates (5 minute weighted average) :
Total Rx (bps) : 273300720 Total Tx (bps) : 70126816
Unicast Rx (Pkts/sec) : 30900 Unicast Tx (Pkts/sec) : 16051
B/Mcast Rx (Pkts/sec) : 0 B/Mcast Tx (Pkts/sec) : 0
Utilization Rx : 27.33 % Utilization Tx : 07.01 %