Intel 1G (82571EB) link bouncing constantly

[Vijay Singh]

Hi, I am on 8.2, and I see that the link on the 1G ports is constantly
bouncing. I have verified cabling etc, and this is seen on multiple
setups.

The NIC exhibiting this is:

em1 at pci0:8:0:1: class=0x020000 card=0x11a48086 chip=0x10a48086 rev=0x06 hdr=0x00
    vendor     = 'Intel Corporation'
    device     = '82571EB Gigabit Ethernet Controller'
    class      = network
    subclass   = ethernet
em2 at pci0:9:0:0: class=0x020000 card=0x11a48086 chip=0x10a48086 rev=0x06 hdr=0x00
    vendor     = 'Intel Corporation'
    device     = '82571EB Gigabit Ethernet Controller'
    class      = network
    subclass   = ethernet

...
got message of size 168 on Mon Nov 19 13:50:25 2012
RTM_IFINFO: iface status change: len 168, if# 12, link: up,
flags:<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST>

got message of size 168 on Mon Nov 19 13:50:25 2012
RTM_IFINFO: iface status change: len 168, if# 11, link: down,
flags:<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST>

got message of size 168 on Mon Nov 19 13:50:25 2012
RTM_IFINFO: iface status change: len 168, if# 12, link: up,
flags:<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST>

got message of size 168 on Mon Nov 19 13:50:25 2012
RTM_IFINFO: iface status change: len 168, if# 12, link: up,
flags:<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST>

got message of size 168 on Mon Nov 19 13:50:25 2012
RTM_IFINFO: iface status change: len 168, if# 12, link: down,
flags:<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST>

got message of size 168 on Mon Nov 19 13:50:25 2012
RTM_IFINFO: iface status change: len 168, if# 11, link: down,
flags:<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST>
...

Has anyone else seen this?

-vijay