We have a 3900 series G2 running 15.0(1)M4. It seems there are alot of differences with the 15.0 code. I was intrigued by the ability to do a port-channel on the router instead of having to use something like HSRP or GLBP for HA. The router is going to be a sip gateway only so I wanted to give it dual links to our core switches for extra protection. I configured the device in the following way and to my surprise it works fine. Whats scary is I would think this would cause a loop because I did not have a port-channel configured on the other side and on the router if I do a show etherchanel summary nothing is present. Any ideas?
show run | beg interface
!
interface Port-channel1
ip address 10.1.210.15 255.255.255.0
hold-queue 150 in
!
interface GigabitEthernet0/0
no ip address
duplex auto
speed auto
!
interface GigabitEthernet0/1
no ip address
duplex auto
speed auto
channel-group 1
!
interface GigabitEthernet0/2
no ip address
duplex auto
speed auto
channel-group 1
!
show etherchannel summary
Flags: D - down P - in port-channel
I - stand-alone s - suspended
R - Layer3 S - Layer2
U - in use
Group Port-channel Ports
-----+------------+-----------------------------------------------------------
CORP_SIP_01#
CORP_SIP_01#show ip int brief
Interface IP-Address OK? Method Status Protocol
GigabitEthernet0/0 unassigned YES manual down down
GigabitEthernet0/1 unassigned YES NVRAM up up
GigabitEthernet0/2 unassigned YES NVRAM up up
Loopback0 unassigned YES unset up up
Port-channel1 10.1.210.15 YES manual up up
