In structure net_device, ifindex is defined as interface index, iflink is defined as unique device indentifier. I've checked the iflink assignments, it's equal to ifindex in most cases, pretty confused. For IPv6, I read the RFC2373. I wonder iflink might be EUI-64 in section 2.5.1 Interface Identifiers? Anyone knows about the iflink? Thanks Shirley Ma IBM Linux Technology Center 15300 SW Koll Parkway Beaverton, OR 97006-6063 Phone: (503) 578-7638 FAX: (503) 578-3228 - : send the line "unsubscribe linux-net" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html