[VLAN] runt frames reported on cisco switch

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



> James Harper wrote:
> > (sorry if I double posted... I only just re-joined the list and it
> > simultaneously rejected this posting and replied with the [VLAN] in
the
> > subject indicating it sent it to the list)
> >
> > I am getting many (>10%) runt frames on a cisco switch on the port
that
> > is connected to a linux router running with vlans. Despite the
reported
> > errors, there are no observed problems with the network.
> 
> I think this is an old cisco bug.

Not sure I agree with you there... two other machines trunking vlans
plugged into the same switch don't have the same problems. The only
difference there is that they are using e100 cards, not via-rhine

> W/regard to the 60 v/s 64 minimum pkt size, the bytes on the wire are
64,
> but that is because the NIC will add a 4 byte CRC to the end of the
> 60-byte payload.

60 bytes is the #define in if_ether.h, and yes it states that it is
'sans FCS', so when it says 60 it really means 64.

What I was getting at though, is that a normal Ethernet minimum frame
size is 64 (60 + FCS). Should the minimum frame size be incremented by 4
when there are vlan headers present?

Something is different about frames sent by the e100 vs the via-rhine,
to verify what I'm thinking, is there a way to check? (can tcpdump tell
me what I want to know, or is the padding invisible to that layer?)

Thanks

James



[Index of Archives]     [Netdev]     [Ethernet Bridging]     [Linux Wireless]     [Kernel Newbies]     [Security]     [Linux for Hams]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux RAID]     [Linux Admin]     [Samba]     [Video 4 Linux]

  Powered by Linux