one pdu per afi. add restart sub-tlv

draft-ymbk-idr-l3nd-ulpc.xml

@@ -182,20 +182,20 @@
       for complexity and hence pain.</t>
 
       <t>If there are multiple BGP sessions on a link, e.g., IPv4 and
-      IPv6, then multiple sets of BGP sub-TLVs MAY BE exchanged within
+      IPv6, then separate BGP ULPC PDUs should be sent, one for each
-      the BGP ULPC PDU or sepatate BGP ULPC PDUs may be sent, one for
+      address family.</t>
-      each address family.</t>
 
       <t>A peer receiving BGP ULPC PDUs has only one active BGP ULPC PDU
       for an particular address family on a specific link at any point
       in time; receipt of a new BGP ULPC PDU for a particular address
-      family replaces any previous one.</t>
+      family replaces the data any previous one; but does not actually
+      affect the session unless there is a BGP Restart Attribute
+      sub-TLV.</t>
 
-      <t>If there are one or more open BGP sessions, receipt of a new
+      <t>If there are one or more open BGP sessions, absent a BGP
-      BGP ULPC PDU SHOULD not affect these sessions and the PDU SHOULD
+      Restart sub-TLV, receipt of a new BGP ULPC PDU SHOULD not affect
-      be discarded.  If a peer wishes to replace an open BGP session,
+      these sessions.  The received data are stored for a future session
-      they MUST first close the running BGP session and then send a new
+      restart.</t>
-      BGP ULPC PDU.</t>
       
       <t>As a link may have multiple encapsulations and multiple
       addresses for an IP encapsulation, which address of which
@@ -226,16 +226,51 @@
       occurances of the same Attr Type, an Error ACK should be
       returned.</t>
         
+      <section anchor="asn" title="BGP Restart">
+
+	<t>When all attributes in PDU have been processed, stop the
+	current BGP session and start a new one with the new attribute
+	set.</t>
+
+	<t>The four or 16 byte Dest IP tells both tha AFI and the IP
+	address of the BGP peer for the session to be restarted.<t>
+
+	<t>If there is no current BGP session to the specified peer,
+	start one.</t>
+
 <!--
-    protocol "Attr Type = 1:8,Attr Len = 4:8,My ASN:32"
+    protocol "Attr Type = 0:8,Attr Len = 4/16:8,Dest IP:128"
 -->
 
+        <figure>
+          <artwork>
+ 0                   1                   2                   3  
+ 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+| Attr Type = 0 |Attr Len = 4/16|                               |
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               +
+|                                                               |
++                                                               +
+|                                                               |
++                                                               +
+|                            Dest IP                            |
++                               +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+|                               |
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            </artwork>
+          </figure>
+        </section>
+
       <section anchor="asn" title="BGP ASN">
 
         <t>The four octet Autonomous System number MUST be specified.
         If the AS Number is less than 32 bits, it is padded with high
         order zeros.</t>
 
+<!--
+    protocol "Attr Type = 1:8,Attr Len = 4:8,My ASN:32"
+-->
+
         <figure>
           <artwork>
  0                   1                   2                   3  
@@ -252,10 +287,6 @@
 
       <section anchor="bgpv4" title="BGP IPv4 Address">
 
-<!--
-    protocol "Attr Type = 2:8,Attr Len = 7:8,My IPv4 Peering Address:32,Prefix Len:8"
--->
-
         <t>The BGP IPv4 Address sub-TLV announces the sender's four octet
         IPv4 BGP peering source address and one octet Prefix Lenth to be
         used by the receiver.  At least one of IPv4 or IPv6 BGP source
@@ -265,6 +296,10 @@
         the AFI/SAFIs to be transported over the peering, see <xref
         target="RFC4760"/>.</t>
 
+<!--
+    protocol "Attr Type = 2:8,Attr Len = 7:8,My IPv4 Peering Address:32,Prefix Len:8"
+-->
+
         <figure>
           <artwork>
  0                   1                   2                   3  
@@ -291,7 +326,7 @@
         target="RFC4760"/> .</t>
 
 <!--
-    protocol "Attr Type = 3:8,Attr Len = 19:8,My IPv6 Peering Address:128,Prefix Len:8"
+    protocol "Attr Type = 3:8,Attr Len = 17:8,My IPv6 Peering Address:128,Prefix Len:8"
 -->
 
         <figure>
@@ -299,7 +334,7 @@
  0                   1                   2                   3  
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-| Attr Type = 3 | Attr Len = 19 |                               |
+| Attr Type = 3 | Attr Len = 17 |                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               +
 |                                                               |
 +                                                               +