diff --git a/lib/radius.js b/lib/radius.js
index 655c15b..803e427 100644
--- a/lib/radius.js
+++ b/lib/radius.js
@@ -2,6 +2,8 @@ var fs = require("fs");
 var util = require("util");
 var crypto = require("crypto");
 var path = require("path");
+var net = require("net");
+var v6 = require('ip-address').v6;
 
 var Radius = {};
 
@@ -485,6 +487,19 @@ Radius.decode_attributes = function(data, attr_hash, vendor, raw_attrs) {
         }
         value = octets.join(".");
         break;
+      case "ipv6prefix":
+        var prefix = value.readUInt8(1);
+        var octets = [];
+        for (var i = 1; i < value.length/2; i++) {
+          octets.push(parseInt(value.readUInt16BE(i*2)).toString(16));
+        }
+        value = octets.join(':')+'/'+prefix;
+        var addr = new v6.Address(octets.join(':'));
+        if (!addr.isValid()) {
+          throw new Error("IPv6 prefix is not valid");
+        }
+        value = addr.correctForm()+'/'+prefix;
+        break;
       case "date":
         value = new Date(value.readUInt32BE(0) * 1000);
         break;
@@ -814,6 +829,26 @@ Radius.encode_attributes = function(packet, attributes, vendor) {
             throw new Error("encode: invalid IP: " + in_value);
           }
           break;
+        case "ipv6prefix":
+          // rfc3162
+          // reserved (1 byte) / prefix-length (1 byte) / prefix (16 bytes)
+          out_value = new Buffer(18);
+          out_value.fill(0);
+          var addr = in_value.split('/');
+          if (addr.length != 2) {
+            throw new Error("encode: invalid IPv6 prefix, no /");
+          }
+          if (!net.isIPv6(addr[0])) {
+            throw new Error("encode: invalid IPv6 prefix");
+          }
+          var prefix = addr[1].slice(1);
+          out_value.writeUInt8(64, 1);
+          addrs = addr[0].split(':');
+          for (var j = 0; j < addrs.length; j++) {
+              if (addrs[j] != '')
+                  out_value.writeUInt16BE(parseInt(addrs[j], 16), j*2+2);
+          }
+          break;
         case "date":
           in_value = Math.floor(in_value.getTime() / 1000);
         case "time":
diff --git a/package.json b/package.json
index b8056c2..72233a0 100644
--- a/package.json
+++ b/package.json
@@ -10,10 +10,14 @@
   },
   "engines": { "node": ">=0.8.0" },
   "devDependencies": {
-    "nodeunit": "~0.8.6"
+    "nodeunit": "~0.8.6",
+    "ip-address": "*"
   },
   "scripts": {
     "test": "nodeunit test"
   },
-  "keywords": ["radius"]
+  "keywords": ["radius"],
+  "dependencies": {
+    "ip-address": "*"
+  }
 }
diff --git a/test/radius.test.js b/test/radius.test.js
index 7ef0267..8316fe8 100755
--- a/test/radius.test.js
+++ b/test/radius.test.js
@@ -928,6 +928,36 @@ module.exports = testCase({
       "User-Password": "降龙十八掌"
     }, decoded.attributes );
 
+    test.done();
+  },
+
+  test_ipv6prefix_encode: function(test) {
+    var decoded = radius.decode({
+      packet: radius.encode({
+        code: 'Access-Request',
+        authenticator: new Buffer('426edca213c1bf6e005e90a64105ca3a', 'hex'),
+        attributes: [['Framed-IPv6-Prefix', '2a05:4680:4::/64']],
+        secret: secret
+      }),
+      secret: secret
+    });
+
+    test.equal( decoded.attributes['Framed-IPv6-Prefix'], '2a05:4680:4::/64' );
+
+    // bad ipv6prefix
+    test.throws(function() {
+      var decoded = radius.decode({
+        packet: radius.encode({
+          code: 'Access-Request',
+          authenticator: new Buffer('426edca213c1bf6e005e90a64105ca3a', 'hex'),
+          attributes: [['Framed-IPv6-Prefix', new Buffer('00402')]],
+          secret: secret
+        }),
+        secret: secret
+      });
+    });
+
     test.done();
   }
+
 });