Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 
New Member

IRB interface: A ping is lost every 10 seconds


I have connected a router 2821, equipped with two gigabit ethernet ports, each one to two different Catalyst.

In order to provide redundancy to its connectivity i configured Integrated IRB at the 2821:

Both ethernet ports are assigned to bridge-group 1 and then, a BVI interface is bounded to this bridge group. This is the basic configuration i did:

bridge 1 protocol ieee

bridge irb

bridge 1 route ip


interface gigabitethernet 0/0

bridge-group 1

no ip address


interface gigabitethernet 0/1

bridge-group 1

no ip address


interface bvi 1

ip address

When pinging continuosly to the default gateway from the 2821 to the hsrp address of both catalyst, i observed that a ping is lost repeteadely exactly every 10 seconds. It makes me wonder that something isn?t working fine.

The same happens when pinging from any catalyst to the 2821 bvi interface

If i remove the integrated irb configuration by assigning the ip address directly to one gigabit interface, it works fine, as pings always works fine from everywhere.

I would like to remark that both catalyst 4506 are running MISTP while the 2821 runs STP 802.1d. Therefore the router is bounded to the CST part of MIST. Anyway, there are no STP unstabilities and CST converges as expected.

Can somebody think why a ping fail every 10 seconds ??

Regards in advance


Re: IRB interface: A ping is lost every 10 seconds

New Member

Re: IRB interface: A ping is lost every 10 seconds

Thank you for your reply!.

In fact i discovered the problem the same day after reading carefully the manual "Configuring Transparent Bridging", which is the first one of your pointers.

the manual states that "When a bridged domain contains learning devices (such as switches or bridges) that can learn the MAC address of a bridge-group virtual interface, the virtual interface must be configured with its own MAC address?separate from the MAC addresses of the bridged interfaces in the bridge group that are associated with the virtual interface. The MAC address is configured by using the mac-address virtual interface command.

That's what i did.

Kind regards.


CreatePlease to create content