Subject: [OSPF] Removal of MOSPF from OSPFv3

From: Acee Lindem <[email-masked]>
Date: Tue, 31 Jul 2007 18:02:57 -0400

MOSPF has never really been fully specified in RFC 2740 and, to the  
best of my knowledge, has never been implemented. Hence, we again had  
some discussions about removing it from the respin. I've made the  
changes but have not submitting them. I've also attempted to reclaim  
the MC-bit in the prefix options since this was never fully specified  
either and has proved to be grossly inadequate to separate unicast  
and multicast topologies. Please send comments ASAP. If I don't hear  
any serious dissent I'll submit the update and we'll do a quick re-WGLC.

Thanks,
Acee

***************
*** 82,89 ****
      addition, option handling has been made more flexible.

      All of OSPF for IPv4's optional capabilities, including demand
!    circuit support, Not-So-Stubby Areas (NSSAs), and the multicast
!    extensions to OSPF (MOSPF) are also supported in OSPF for IPv6.

--- 82,89 ----
      addition, option handling has been made more flexible.

      All of OSPF for IPv4's optional capabilities, including demand
!    circuit support and Not-So-Stubby Areas (NSSAs) are also  
supported in
!    OSPF for IPv6.

***************
*** 828,844 ****
      LSAs, network-LSAs, inter-area-prefix-LSAs, inter-area-router- 
LSAs,
      and intra-area-prefix-LSAs.  LSAs with unknown LS type, U-bit  
set to
      1 (flood even when unrecognized) and area scope also appear in the
!    area data structure.  IPv6 routers implementing MOSPF add group-
!    membership-LSAs to the area data structure.  NSSA-LSAs are also
!    included in an NSSA area's data structure.

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   3.1.2.  The Interface Data structure
--- 828,844 ----
      LSAs, network-LSAs, inter-area-prefix-LSAs, inter-area-router- 
LSAs,
      and intra-area-prefix-LSAs.  LSAs with unknown LS type, U-bit  
set to
      1 (flood even when unrecognized) and area scope also appear in the
!    area data structure.  NSSA-LSAs are also included in an NSSA area's
!    data structure.
!

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   3.1.2.  The Interface Data structure
***************
*** 1086,1094 ****
      o  The Options field within Database Description packets has moved
         around, getting larger in the process.  More options bits  
are now
         possible.  Those that MUST be set correctly in Database
!       Description packets are: The MC-bit is set if and only if the
!       router is forwarding multicast datagrams according to the MOSPF
!       specification in [MOSPF], and the DC-bit is set if and only  
if the
         router wishes to suppress the sending of Hellos over the  
interface
         (see [DEMAND]).  Unrecognized bits in the Database Description
         packet's Options field should be cleared.
--- 1086,1092 ----
      o  The Options field within Database Description packets has moved
         around, getting larger in the process.  More options bits  
are now
         possible.  Those that MUST be set correctly in Database
!       Description packets are: The DC-bit is set if and only if the
         router wishes to suppress the sending of Hellos over the  
interface
         (see [DEMAND]).  Unrecognized bits in the Database Description
         packet's Options field should be cleared.
***************
*** 1577,1591 ****
      should be set unless the router will not participate in transit  
IPv6
      routing.  The E-bit should be clear if and only if the attached  
area
      is an OSPF stub or OSPF NSSA area.  The E-bit should always be  
set in
!    AS scoped LSAs.  The MC-bit should be set if and only if the router
!    is running MOSPF and the LSA is to be used in the multicast SPF
!    computation (see [MOSPF]).  The N-bit should be set if and only if
!    the attached area is an OSPF NSSA area.  The R-bit should be set
!    unless the router will not participate in any transit routing.  The
!    DC-bit should be set if and only if the router can correctly  
process
!    the DoNotAge bit when it appears in the LS age field of LSAs (see
!    [DEMAND]).  All unrecognized bits in the Options field should be
!    cleared.

      The V6-bit and R-bit are only examined in Router-LSAs during  
the SPF
      computation.  In other LSA types containing options, they are  
set for
--- 1577,1588 ----
      should be set unless the router will not participate in transit  
IPv6
      routing.  The E-bit should be clear if and only if the attached  
area
      is an OSPF stub or OSPF NSSA area.  The E-bit should always be  
set in
!    AS scoped LSAs.  The N-bit should be set if and only if the  
attached
!    area is an OSPF NSSA area.  The R-bit should be set unless the  
router
!    will not participate in any transit routing.  The DC-bit should be
!    set if and only if the router can correctly process the DoNotAge  
bit
!    when it appears in the LS age field of LSAs (see [DEMAND]).  All
!    unrecognized bits in the Options field should be cleared.

      The V6-bit and R-bit are only examined in Router-LSAs during  
the SPF
      computation.  In other LSA types containing options, they are  
set for
***************
*** 1603,1610 ****
      State ID fields.

      To the left of the Options field, the router capability bits V, E,
!    and B should be set according to Section 12.4.1 of [OSPFV2].  Bit W
!    should be coded according to [MOSPF].

      Each of the router's interfaces to the area are then described by
      appending "link descriptions" to the router-LSA.  Each link
--- 1600,1606 ----
      State ID fields.

      To the left of the Options field, the router capability bits V, E,
!    and B should be set according to Section 12.4.1 of [OSPFV2].

      Each of the router's interfaces to the area are then described by
      appending "link descriptions" to the router-LSA.  Each link
***************
*** 1732,1748 ****

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         Designated Router.

      o  The Options field in the network-LSA is set to the logical  
OR of
         the Options fields contained within the link's associated link-
!       LSAs.  In this way, the network link exhibits a capability  
when at
!       least one of the link's routers requests that the capability be
         advertised.

      As an example, assuming that Router RT4 has been elected  
Designated
--- 1732,1749 ----

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         Designated Router.

      o  The Options field in the network-LSA is set to the logical  
OR of
         the Options fields contained within the link's associated link-
!       LSAs corresponding to fully adjacent neighbors.  In this way,  
the
!       network link exhibits a capability when at least one fully
!       adjacent neighbor on the link requests that the capability be
         advertised.

      As an example, assuming that Router RT4 has been elected  
Designated
***************
*** 1787,1801 ****

!
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!    o  The NU-bit in the PrefixOptions field should be clear.  The  
coding
!       of the MC-bit depends upon whether, and if so how, MOSPF is
!       operating in the routing domain (see [MOSPF]).

      o  Link-local addresses MUST never be advertised in inter-area-
         prefix-LSAs.
--- 1788,1799 ----

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!    o  The NU-bit in the PrefixOptions field should be clear.

      o  Link-local addresses MUST never be advertised in inter-area-
         prefix-LSAs.
***************
*** 1894,1916 ****
         Address Prefix fields embedded within the LSA body.  Network  
Mask
         is no longer specified.

!    o  The NU-bit in the PrefixOptions field should be clear.  The  
coding
!       of the MC-bit depends upon whether, and if so how, MOSPF is
!       operating in the routing domain (see [MOSPF]).
!

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!    o  Link-local addresses can never be advertised in AS-external- 
LSAs.

-    o  The forwarding address is present in the AS-external-LSA if and
-       only if the AS-external-LSA's bit F is set.

      o  The external route tag is present in the AS-external-LSA if and
         only if the AS-external-LSA's bit T is set.
--- 1892,1911 ----
         Address Prefix fields embedded within the LSA body.  Network  
Mask
         is no longer specified.

!    o  The NU-bit in the PrefixOptions field should be clear.

+    o  Link-local addresses can never be advertised in AS-external- 
LSAs.

+    o  The forwarding address is present in the AS-external-LSA if and
+       only if the AS-external-LSA's bit F is set.

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      o  The external route tag is present in the AS-external-LSA if and
         only if the AS-external-LSA's bit T is set.
***************
*** 1982,1990 ****
         Address Prefix fields embedded within the LSA body.  Network  
Mask
         is no longer specified.

!    o  The NU-bit in the PrefixOptions field should be clear.  The  
coding
!       of the MC-bit depends upon whether, and if so how, MOSPF is
!       operating in the routing domain (see [MOSPF]).

      o  Link-local addresses can never be advertised in NSSA-LSAs.

--- 1971,1977 ----
         Address Prefix fields embedded within the LSA body.  Network  
Mask
         is no longer specified.

!    o  The NU-bit in the PrefixOptions field should be clear.

      o  Link-local addresses can never be advertised in NSSA-LSAs.

***************
*** 2450,2475 ****
      area-prefix-LSAs (0x2003), inter-area-router-LSAs (0x2004),  
NSSA-LSAs
      (0x2007), AS-external-LSAs (0x4005), link-LSAs (0x0008), and  
Intra-
      Area-Prefix-LSAs (0x2009) are assumed to be understood by all
!    routers.  However, not all LS types are understood by all routers,
!    For example, the group-membership-LSA (0x2006) is understood  
only by
!    MOSPF routers and since it has its U-bit set to 0.  This LS Type
!    should only be flooded to a non-MOSPF neighbor (determined by
!    examining the MC-bit in the neighbor's Database Description  
packets'
!    Options field) when the neighbor is Designated Router or Backup
!    Designated Router for the attached link.
!
!    The previous paragraph solves a problem for IPv4 OSPF extensions  
such
!
!
!
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!
!
!    as MOSPF, which require that the Designated Router support the
!    extension in order to have the new LSA types flooded across  
broadcast
!    and NBMA networks (see Section 10.2 of [MOSPF]).

   3.5.3.  Installing LSAs in the database

--- 2422,2436 ----
      area-prefix-LSAs (0x2003), inter-area-router-LSAs (0x2004),  
NSSA-LSAs
      (0x2007), AS-external-LSAs (0x4005), link-LSAs (0x0008), and  
Intra-
      Area-Prefix-LSAs (0x2009) are assumed to be understood by all
!    routers.  However, all LS types MAY not be understood by all  
routers.
!    For example, a new LSA type with its U-bit set to 0 MAY only be
!    understood by a subset of routers.  This new LS Type should only be
!    flooded to an OSPF neighbor that understands the LS type or when  
the
!    neighbor that doesn't understand it is Designated Router or Backup
!    Designated Router for the attached link.  This allows the LSA to be
!    flooded on the local link even if either the router elected
!    Designated Router or Backup Designated Router doesn't understand  
the
!    LS type.

   3.5.3.  Installing LSAs in the database

***************
*** 3395,3406 ****
      neighbor relationships from forming (e.g., the E-bit below); these
      mismatches are discovered through the sending and receiving of  
Hello
      packets.  Some option mismatches prevent particular LSA types from
!    being flooded across adjacencies (e.g., the MC-bit below); these  
are
!    discovered through the sending and receiving of Database  
Description
!    packets.  Some option mismatches prevent routers from being  
included
!    in one or more of the various routing calculations because of their
!    reduced functionality (again, the MC-bit is an example); these
!    mismatches are discovered by examining LSAs.

      Seven bits of the OSPF Options field have been assigned.  Each  
bit is
      described briefly below.  Routers should reset (i.e., clear)
--- 3395,3405 ----
      neighbor relationships from forming (e.g., the E-bit below); these
      mismatches are discovered through the sending and receiving of  
Hello
      packets.  Some option mismatches prevent particular LSA types from
!    being flooded across adjacencies these are discovered through the
!    sending and receiving of Database Description packets.  Some option
!    mismatches prevent routers from being included in one or more of  
the
!    various routing calculations because of their reduced  
functionality;
!    these mismatches are discovered by examining LSAs.

      Seven bits of the OSPF Options field have been assigned.  Each  
bit is
      described briefly below.  Routers should reset (i.e., clear)
***************
*** 3414,3429 ****

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                                  1                    2
!            0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8  9 0  1  2  3
!           +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+-+-+--+--+--+
!           | | | | | | | | | | | | | | | | |*|*|DC|R|N|MC| E|V6|
!           +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+-+-+--+--+--+

                              The Options field

--- 3413,3429 ----

!
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                                  1                    2
!            0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8  9 0 1  2  3
!           +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+-+-+-+--+--+
!           | | | | | | | | | | | | | | | | |*|*|DC|R|N|x| E|V6|
!           +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+-+-+-+--+--+

                              The Options field

***************
*** 3438,3446 ****
         This bit describes the way AS-external-LSAs are flooded, as
         described in Sections 3.6, 9.5, 10.8, and 12.1.2 of [OSPFV2].

!    MC-bit
!       This bit describes whether IP multicast datagrams are forwarded
!       according to the specifications in [MOSPF].

      N-bit
         This bit indicates whether or not the router is attached to an
--- 3438,3447 ----
         This bit describes the way AS-external-LSAs are flooded, as
         described in Sections 3.6, 9.5, 10.8, and 12.1.2 of [OSPFV2].

!    x-Bit
!       This bit was previously used by MOSPF (see [MOSPF]) which has  
been
!       deprecated for OSPFv3.  It should be set to 0 and ignored upon
!       reception.  It may be reused in the future.

      N-bit
         This bit indicates whether or not the router is attached to an
***************
*** 4021,4038 ****
      cases or are to be marked as not readvertisable in others.

                        0  1  2  3  4  5  6  7
!                     +--+--+--+--+--+--+--+--+
!                     |  |  |  |DN| P|MC|LA|NU|
!                     +--+--+--+--+--+--+--+--+

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                            The Prefix Options field
--- 4021,4038 ----
      cases or are to be marked as not readvertisable in others.

                        0  1  2  3  4  5  6  7
!                     +--+--+--+--+--+-+--+--+
!                     |  |  |  |DN| P|x|LA|NU|
!                     +--+--+--+--+--+-+--+--+

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                            The Prefix Options field
***************
*** 4050,4059 ****
         Section 3.4.3.9.  An implementation MAY also set the LA-bit for
         prefixes advertised with a host PrefixLength (128).

!    MC-bit
!       The "multicast" capability bit.  If set, the prefix should be
!       included in IPv6 multicast routing calculations.  If not set, it
!       should be excluded.

      P-bit
         The "propagate" bit.  Set on NSSA area prefixes that should be
--- 4050,4060 ----
         Section 3.4.3.9.  An implementation MAY also set the LA-bit for
         prefixes advertised with a host PrefixLength (128).

!    x-bit
!       This bit was previously defined as a "multicast" capability bit.
!       However, the use was never adequately specified and it is being
!       deprecated.  It is set to 0 and ignored upon reception.  It  
may be
!       reused in the future.

      P-bit
         The "propagate" bit.  Set on NSSA area prefixes that should be
***************
*** 4193,4209 ****

      The LSA function codes are defined as follows.  The origination  
and
      processing of these LSA function codes are defined elsewhere in  
this
!    document, except for the group-membership-LSA (see [MOSPF]) and the
!    NSSA-LSA (see [NSSA]).  As shown below, each LSA function code also

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!    implies a specific setting for the U, S1, and S2 bits.

               LSA function code   LS Type   Description
--- 4193,4210 ----

      The LSA function codes are defined as follows.  The origination  
and
      processing of these LSA function codes are defined elsewhere in  
this
!    document, except for the NSSA-LSA (see [NSSA]) and 0x2006 which was
!    previously used by MOSPF (see [MOSPF]).  MOSPF has been deprecated

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!    for OSPFv3.  As shown below, each LSA function code also implies a
!    specific setting for the U, S1, and S2 bits.

               LSA function code   LS Type   Description
***************
*** 4213,4219 ****
               3                   0x2003    Inter-Area-Prefix-LSA
               4                   0x2004    Inter-Area-Router-LSA
               5                   0x4005    AS-external-LSA
!             6                   0x2006    Group-membership-LSA
               7                   0x2007    NSSA-LSA
               8                   0x0008    Link-LSA
               9                   0x2009    Intra-Area-Prefix-LSA
--- 4214,4220 ----
               3                   0x2003    Inter-Area-Prefix-LSA
               4                   0x2004    Inter-Area-Router-LSA
               5                   0x4005    AS-external-LSA
!             6                   0x2006    Deprecated (May be reused)
               7                   0x2007    NSSA-LSA
               8                   0x0008    Link-LSA
               9                   0x2009    Intra-Area-Prefix-LSA
***************
*** 4272,4278 ****
         +-+-+-+--+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 
+-+-+
         |        LS Checksum             |             
Length             |
         +-+-+-+--+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 
+-+-+
!       |  0  |Nt|W|V|E|B|             
Options                            |
         +-+-+-+--+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 
+-+-+
         |     Type       |       0       |           
Metric               |
         +-+-+-+--+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 
+-+-+
--- 4272,4278 ----
         +-+-+-+--+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 
+-+-+
         |        LS Checksum             |             
Length             |
         +-+-+-+--+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 
+-+-+
!       |  0  |Nt|x|V|E|B|             
Options                            |
         +-+-+-+--+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 
+-+-+
         |     Type       |       0       |           
Metric               |
         +-+-+-+--+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 
+-+-+
***************
*** 4326,4336 ****
      Bit B
         When set, the router is an area border router (B is for  
border).

!    Bit W
!       When set, the router is a wild-card multicast receiver.  When
!       running MOSPF, these routers receive all multicast datagrams,
!       regardless of destination.  See Sections 3, 4, and A.2 of  
[MOSPF]
!       for details.

      Bit Nt
         When set, the router is an NSSA border router that is
--- 4326,4335 ----
      Bit B
         When set, the router is an area border router (B is for  
border).

!    Bit x
!       This bit was previously used by MOSPF (see [MOSPF]) which has  
been
!       deprecated for OSPFv3.  It should be set to 0 and ignored upon
!       reception.  It may be reused in the future.

      Bit Nt
         When set, the router is an NSSA border router that is
***************
*** 5796,5806 ****
--- 5796,5814 ----
      o  Add new prefix options and options field bits added in this
         document to the IANA considerations.  Refer to Section 5.

+ E.18.  Changes from the 16 Version to the 17 Version

+    The section contains list of changes from version 16 to version 17:

+    o  Changes to deprecate MOSPF for OSPFv3.  Refer to Appendix A.2,
+       Appendix A.4.2.1, and Appendix A.4.3.

+    o  Deprecate the MC-bit in the prefix options which was never
+       adequated specified.  Refer to Appendix A.4.1.1.

+    o  Clarify the setting of the options in the network-LSA.  Refer to
+       Appendix A.4.4.

Acee-iMac:~/ietf/xml2rfc acee$

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