If the peer group is for eBGP (as dictated by bgpPeergrArea), this field indicates that all routes with IPv4 address family received from peers in this peer group should have an extended community attached containing the bandwidth of the link to the eBGP peer when the routes are propagated to iBGP peers, as per draft-ietf-idr-link-bandwidth (subject to send_ext_comm configuration). Changing the value of this object while peers in the peer group are active, causes DC-BGP to review whether the extended community should be added to or removed from routes received from those peers (as appropriate) and propagates any changes to its iBGP peers. This setting has no effect on routes with address family other than IPv4.