Anand Raj Manickam [off-list ref] :

On Thu, Jan 27, 2011 at 8:37 PM, Francois Romieu [off-list ref] wrote:

quoted

Anand Raj Manickam [off-list ref] :

[...]

quoted

- ip addr show

3: eth0: <BROADCAST,MULTICAST,UP,10000> mtu 1500 qdisc pfifo_fast qlen 1000
    link/ether 00:17:54:00:f6:62 brd ff:ff:ff:ff:ff:ff
    inet 172.16.1.1/16 brd 172.16.255.255 scope global eth0
    inet6 fe80::217:54ff:fe00:f662/64 scope link
       valid_lft forever preferred_lft forever

8: eth0.50@eth0: <BROADCAST,MULTICAST,UP,10000> mtu 1500 qdisc noqueue
    link/ether 00:17:54:00:f6:62 brd ff:ff:ff:ff:ff:ff
    inet 172.16.10.10/24 brd 172.16.10.255 scope global eth0.50
    inet6 fe80::217:54ff:fe00:f662/64 scope link
       valid_lft forever preferred_lft forever

Could you try again after issuing :

ip addr del 172.16.1.1/16 brd 172.16.255.255 dev eth0

then send the unabbreviated "ip addr show" and "ip route show all" if
things do not perform better.

(no iptables / ip rules wizardry, right ?)

[...]

quoted

- ethtool -k eth0

Offload parameters for eth0:
rx-checksumming: on
tx-checksumming: off
scatter-gather: off
tcp segmentation offload: off
udp fragmentation offload: off
generic segmentation offload: off

Ok.

[...]

quoted

I do not get the "VLAN tag gets stripped" concept, especially on Tx.
Does it mean "no packet" or "a packet whose content is wrong" ?

Sorry for not being clear ;-)

When we transmit a packet with VLAN TAG , the TAG get stripped when
transmitted through the device , the other end trunk port / sniffer
does NOT see a TAG.
Similarly , when a VLAN Tagged packet is sent from the other end , The
TAG gets stripped by the device , We DONOT see the tag .

But the data flows in both directions, right ?

I use tcpdump -i eth0 -n -nn -e vlan 50
to see if the packets are gettin tagged or NOT .

The same config works on forcedeth

What do you call "same config" ?

I am mildly convinced that your config is simple enough to isolate a
driver level vlan problem.

-- 
Ueimor