Broadcom bge and 802.1Q vlan tags

Roubícek Zdenek (T-Systems PragoNet) Zdenek.Roubicek at
Tue Oct 12 01:36:30 PDT 2004

 Hello current

 I have run into a problem with my Broadcom NIC (Dell LATITUDE D600). I am not able to detect 802.1Q tags on incoming interface with ethereal or tcpdump. All incoming packets seems like they are not coming through trunk but as native ETH frames, ie. the vlan tag is missing, probably removed before being passed to tcpdump?

No I have not tested NIC's behaviour on 4.X, but I is working with linux (2.6.something kernel probably?)

Any ideas what to modify or set so I can detect vlan_tag would be very apreciated.

Regards, zdenek

Here is what I believe to be of interest:

spaca-ntb# uname -a
FreeBSD 5.3-BETA7 FreeBSD 5.3-BETA7 #2: Mon Oct 11 22:59:16 CEST 2004     root at  i386

spaca-ntb# dmesg | grep bge
bge0: <Broadcom BCM5705M Gigabit Ethernet, ASIC rev. 0x3001> mem 0xfaff0000-0xfaffffff irq 11 at device 0.0 on pci2
miibus0: <MII bus> on bge0

spaca-ntb# pciconf -v -l
bge0 at pci2:0:0:  class=0x020000 card=0x865d1028 chip=0x165d14e4 rev=0x01 hdr=0x00
    vendor   = 'Broadcom Corporation'
    device   = 'BCM5705M Broadcom NetXtreme Gigabit Ethernet'
    class    = network
    subclass = ethernet

spaca-ntb# ifconfig
        inet6 fe80::20d:56ff:fee2:edc4%bge0 prefixlen 64 scopeid 0x1
        ether 00:0d:56:e2:ed:c4
        media: Ethernet 100baseTX <full-duplex>
        status: active
plip0: flags=108810<POINTOPOINT,SIMPLEX,MULTICAST> mtu 1500
lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384
        inet netmask 0xff000000
        inet6 ::1 prefixlen 128
        inet6 fe80::1%lo0 prefixlen 64 scopeid 0x3
vlan100: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        inet6 fe80::20d:56ff:fee2:edc4%vlan100 prefixlen 64 scopeid 0x4
        inet netmask 0xffffff00 broadcast
        ether 00:0d:56:e2:ed:c4
        media: Ethernet 100baseTX <full-duplex>
        status: active
        vlan: 100 parent interface: bge0

spaca-ntb# sysctl -a | grep fastforw
net.inet.ip.fastforwarding: 0

spaca-ntb# tcpdump -n -v -i bge0 host
tcpdump: WARNING: bge0: no IPv4 address assigned
tcpdump: listening on bge0, link-type EN10MB (Ethernet), capture size 96 bytes
10:26:07.764778 IP (tos 0x10, ttl  62, id 16761, offset 0, flags [DF], length: 52) > . [tcp sum ok] ack 825352345 win 15136 <nop,nop,timestamp 527892104 104052>
10:26:08.757016 IP (tos 0x10, ttl  62, id 16762, offset 0, flags [DF], length: 52) > . [tcp sum ok] ack 241 win 15136 <nop,nop,timestamp 527892203 104152>
10:26:09.756784 IP (tos 0x10, ttl  62, id 16763, offset 0, flags [DF], length: 52) > . [tcp sum ok] ack 465 win 15136 <nop,nop,timestamp 527892303 104252>

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