--- v2.4.18/linux/Documentation/filesystems/proc.txt	Mon Nov 26 23:05:49 2001
+++ linux/Documentation/filesystems/proc.txt	Tue Mar  5 01:04:43 2002
@@ -1549,6 +1549,19 @@
 Do multicast routing. The kernel needs to be compiled with CONFIG_MROUTE and a
 multicast routing daemon is required.
 
+medium_id
+---------
+
+Integer value used to differentiate the devices by the medium they
+are attached to. Two devices can have different id values when
+the broadcast packets are received only on one of them.
+The default value 0 means that the device is the only interface
+to its medium, value of -1 means that medium is not known.
+
+Currently, it is used to change the proxy_arp behavior:
+the proxy_arp feature is enabled for packets forwarded between
+two devices attached to different medium.
+
 proxy_arp
 ---------
 
--- v2.4.18/linux/Documentation/networking/ip-sysctl.txt	Sun Mar  3 00:23:58 2002
+++ linux/Documentation/networking/ip-sysctl.txt	Tue Mar  5 01:43:33 2002
@@ -358,6 +358,18 @@
 	Do multicast routing. The kernel needs to be compiled with CONFIG_MROUTE
 	and a multicast routing daemon is required.
 
+medium_id - INTEGER
+
+	Integer value used to differentiate the devices by the medium they
+	are attached to. Two devices can have different id values when
+	the broadcast packets are received only on one of them.
+	The default value 0 means that the device is the only interface
+	to its medium, value of -1 means that medium is not known.
+
+	Currently, it is used to change the proxy_arp behavior:
+	the proxy_arp feature is enabled for packets forwarded between
+	two devices attached to different medium.
+
 proxy_arp - BOOLEAN
 	Do proxy arp.