--- wikisrc/users/kefren.mdwn	2010/05/21 05:59:30	1.1
+++ wikisrc/users/kefren.mdwn	2010/06/28 08:31:35	1.2
@@ -1 +1,77 @@
-Under slow and heavy construction.
+#Some quick info about MPLS:
+
+You need to compile your kernel with options MPLS and psuedo-device ifmpls
+For pure LSR - that only switch labels without encap/decap from other protocols (e.g. INET) you need only to work on routing table. For example:
+
+<pre># route add -mpls 41 -tag 25 -inet 193.28.151.97
+add host 41: gateway 193.28.151.97
+# route add -mpls 42 -tag 30 -inet 193.28.151.97
+add host 42: gateway 193.28.151.97
+# route add -mpls 51 -tag 25 -inet 193.28.151.97
+add host 51: gateway 193.28.151.97</pre>
+
+Translation of first line: if it receives an MPLS frame with label 41 forward it to INET next-hop 193.28.151.97, tagged with label 25
+
+You also need to tweak sysctl to accept and forward MPLS:
+
+<pre># sysctl -w net.mpls.accept=1
+net.mpls.accept: 0 -> 1
+# sysctl -w net.mpls.forwarding=1
+net.mpls.forwarding: 0 -> 1</pre>
+
+
+Verify routes with route get or better with netstat -nrT:
+
+<pre>
+...
+MPLS:
+Destination        Gateway            Flags    Refs      Use    Mtu     Tag Interface
+41                 193.28.151.97      UGHS        0    37241      -      25 sk0
+42                 193.28.151.97      UGHS        0        0      -      30 sk0
+51                 193.28.151.97      UGHS        0        0      -      25 sk0
+</pre>
+
+#Interacting with other protocols
+
+If you want to also decapsulate/encapsulate from MPLS to some other protocol (like INET or INET6), you have to create an mpls interface and put in up: ifconfig mpls0 create up. YOU NEED TO ADD AN ADDRESS OF THAT PROTOCOL ON THIS INTERFACE - whenever that address is private or not.
+
+E.g. for INET - setting a fictitious address:
+
+<pre>
+# ifconfig mpls0 create up
+# ifconfig mpls0 1.1.1.1/32
+</pre>
+
+After that create routes like this - use -ifa flag in order to avoid self-generated packets having source address 1.1.1.1, but route them thru mpls0 interface.
+
+<pre>
+# route add 204.152.190.0/24 -ifa 193.28.151.105 -ifp mpls0 -tag 25 -inet 193.28.151.97
+add net 204.152.190.0: gateway 193.28.151.97
+</pre>
+
+Verify the route:
+
+<pre>
+# route -n get 204.152.190.0/24
+   route to: 204.152.190.0
+destination: 204.152.190.0
+       mask: 255.255.255.0
+    gateway: 193.28.151.97
+        Tag: 25
+ local addr: 193.28.151.105
+  interface: mpls0
+      flags: <UP,GATEWAY,DONE,STATIC>
+ recvpipe  sendpipe  ssthresh  rtt,msec    rttvar  hopcount      mtu     expire
+       0         0         0       813       344         0         0         0 
+sockaddrs: <DST,GATEWAY,NETMASK,IFP,IFA,TAG>
+</pre>
+
+or with netstat -rT:
+<pre>
+...
+204.152.190/24     193.28.151.97      UGS         0    95362      -      25 mpls0
+...
+</pre>
+
+
+I'm working on LDP daemon, it should be available in a couple of weeks.