diff --git a/ChangeLog b/ChangeLog
index 0a02ca5c..71e7d313 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -26,6 +26,8 @@ version 3.21 ()
       rather than assuming they are the same.
     * Capture port VLANs on Cisco interfaces which are configured for
       trunking but are not in operational trunking mode
+    * Correct munging of dot1dStpPortDesignatedPort in stp_p_port() and
+      i_stp_port() methods
 
 version 3.20 (2014-09-08)
 
diff --git a/Info.pm b/Info.pm
index 5d820392..f199f63e 100644
--- a/Info.pm
+++ b/Info.pm
@@ -3411,7 +3411,7 @@ sub munge_mac {
 
 =item munge_prio_mac()
 
-Takes an 8-byte octet stream (HEX-STRING) and returns a colon separated ASCII
+Takes an 2-byte octet stream (HEX-STRING) and returns a colon separated ASCII
 hex string.
 
 =cut
@@ -3425,6 +3425,22 @@ sub munge_prio_mac {
     return;
 }
 
+=item munge_prio_port()
+
+Takes an 8-byte octet stream (HEX-STRING) and returns a colon separated ASCII
+hex string.
+
+=cut
+
+sub munge_prio_port {
+    my $mac = shift;
+    return unless defined $mac;
+    return unless length $mac;
+    $mac = join( ':', map { sprintf "%02x", $_ } unpack( 'C*', $mac ) );
+    return $mac if $mac =~ /^([0-9A-F][0-9A-F]:){1}[0-9A-F][0-9A-F]$/i;
+    return;
+}
+
 =item munge_octet2hex()
 
 Takes a binary octet stream and returns an ASCII hex string
diff --git a/Info/Bridge.pm b/Info/Bridge.pm
index ba654e0d..d3f3d5cd 100644
--- a/Info/Bridge.pm
+++ b/Info/Bridge.pm
@@ -128,7 +128,7 @@ $VERSION = '3.20';
     'stp_root'         => \&SNMP::Info::munge_mac,
     'stp_p_root'       => \&SNMP::Info::munge_prio_mac,
     'stp_p_bridge'     => \&SNMP::Info::munge_prio_mac,
-    'stp_p_port'       => \&SNMP::Info::munge_prio_mac,
+    'stp_p_port'       => \&SNMP::Info::munge_prio_port,
     'qb_cv_egress'     => \&SNMP::Info::munge_port_list,
     'qb_cv_untagged'   => \&SNMP::Info::munge_port_list,
     'qb_v_egress'      => \&SNMP::Info::munge_port_list,