Cisco 837 Bridge / Spanning Tree Protocol question

Hi,
I have a new Cisco 837 ADSL/Router/Switch that I have connected to my SBC DSL internet account.  I have static IP and have setup connectivity to SBC's network by configuring a bridge to their network.  The configuration works and I have connectivity to the internet, but I'm noticing that the Cisco router is sending out a Spanning Tree Protocol message approximately every 2 seconds.  This doesn't seem like it would be a normal condition to me.  Is it?  I have attached my current config below as well as the STP message captured from ethereal.

My question is:  Is this normal or do I need changes to my config to correct this issue?

Thanks,

Kevin


Ethereal output:
==================================
      1 0.000000    Cisco_42:1d:14        Spanning-tree-(for-bridges)_00 STP      Conf. Root = 32768/00:13:c3:42:1d:14  Cost = 0  Port = 0x8006
      2 2.000133    Cisco_42:1d:14        Spanning-tree-(for-bridges)_00 STP      Conf. Root = 32768/00:13:c3:42:1d:14  Cost = 0  Port = 0x8006
      4 4.000129    Cisco_42:1d:14        Spanning-tree-(for-bridges)_00 STP      Conf. Root = 32768/00:13:c3:42:1d:14  Cost = 0  Port = 0x8006


Cisco 837 config:
===================================================

Current configuration : 1298 bytes
!
version 12.3
no service pad
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname rwc-1
!
enable secret 5 $1$.48J$mNUuDQC0FIUV9USBYKyR51
!
no aaa new-model
ip subnet-zero
no ip routing
no ip domain lookup
ip dhcp excluded-address 10.11.12.1
!
ip dhcp pool dhcp-1
   network 10.11.12.0 255.255.255.0
   default-router 10.11.12.1
   dns-server 206.13.28.12 206.13.29.12
!
!
ip audit notify log
ip audit po max-events 100
no ftp-server write-enable
!
!
!
!
!
!
!
interface Ethernet0
 no ip address
 no ip route-cache
 bridge-group 1
 hold-queue 100 out
!
interface ATM0
 no ip address
 no ip route-cache
 no atm ilmi-keepalive
 pvc 0/35
  encapsulation aal5snap
 !
 dsl operating-mode auto
 bridge-group 1
!
interface FastEthernet1
 no ip address
 duplex auto
 speed auto
!
interface FastEthernet2
 no ip address
 duplex auto
 speed auto
!
interface FastEthernet3
 no ip address
 duplex auto
 speed auto
!
interface FastEthernet4
 no ip address
 speed auto
!
interface FastEthernet4
 no ip address
 duplex auto
 speed auto
!
ip classless
ip http server
no ip http secure-server
!
bridge 1 protocol ieee
!
line con 0
 no modem enable
line aux 0
line vty 0 4
!
scheduler max-task-time 5000
!
end