Technical Summary
This document defines a new PIM Hello option to advertise an
interface identifier that can be used by PIM protocols to uniquely
identify an interface of a neighboring router.
Working Group Summary
There is consensus within the PIM WG to publish the document. The
participation has been with individuals from a variety of vendors and
providers. The authors made minor changes based upon feedback during the
wglc.
Document Quality
There exists at least one implementation of this protocol for which IANA
early allocation was performed.
Personnel
Mike McBride is the Document Shepherd
Adrian Farrel is the Responsible Area Director
RFC Editor Note
Section1 New final paragraph
NEW
All multi-byte integers in this specification are transmitted in
network byte order (i.e. most-significant byte first).
END
Section 2
OLD
The Interface Identifier option is used to identify which interface
of a neighboring router a PIM Hello [RFC4601] is sent on. This
allows PIM protocols to refer to, or identify, a particular interface
on a neighboring router.
NEW
The Interface Identifier option is used to identify through which
interface of a neighboring router a PIM Hello [RFC4601] was sent.
This allows PIM protocols to refer to, or identify, a particular
interface on a neighboring router.
END
Section 2.1
OLD
The 32 bit Local Interface Identifier is selected such that it is
unique among the router's PIM enabled interfaces. That is, there
MUST NOT be two PIM interfaces with the same Local Interface
Identifier. While an interface is up, the Identifier MUST always be
the same once it has been allocated. If an interface goes down and
comes up, the router SHOULD use the same Identifier. Many systems
make use of an ifIndex [RFC1213], which can be used as a Local
Interface Identifier.
The Local Interface Identifier MUST be non-zero. The reason for
this, is that some protocols may want to only optionally refer to an
Interface using the Interface Identifier Hello option, and use the
value of 0 to show that it is not referred to. Note that the value
of 0 is not a valid ifIndex as defined in [RFC1213].
NEW
The 32 bit Local Interface Identifier is selected such that it is
unique among the router's PIM enabled interfaces. That is, there
MUST NOT be two PIM interfaces with the same Local Interface
Identifier. While an interface is up, the Identifier MUST always be
the same once it has been allocated. If an interface goes down and
comes up, the router SHOULD use the same Identifier. If a node goes
down and comes up again. the Identifier for each interface MAY
change. Many systems make use of an ifIndex [RFC2863] as a Local
Interface Identifier.
The Local Interface Identifier MUST be non-zero. The reason for
this, is that some protocols may have messages that optionally
reference an Interface Identifier, and they may use the value of 0
to show that no Interface Identifier is being referenced. Note that
the value of 0 is not a valid ifIndex as defined in [RFC2863].
END
Section 2.2
OLD
The 32 bit Router Identifier may be used to uniquely identify the
router. It may be selected to be unique within some administrative
domain, or possibly globally unique. The requirements for the scope
in which it needs to be unique depend on the protocol that utilizes
this. A router implementation MAY choose an IPv4 unicast address
assigned to the router as the Router Identifier, but MUST allow the
identifier to be configured manually. Protocols such as BGP
[RFC4271] and OSPFv2 [RFC2328] are other protocols making use of 32
bit identifiers for routers. One may use the same identifier to
construct the Interface Identifier option, provided it meets the
stability and uniqueness requirements of protocols making use of this
option.
NEW
The 32 bit Router Identifier may be used to uniquely identify the
router. The requirements for the scope in which the Router Identifier
needs to be unique depend on the protocols that utilize it. It may
need to be unique within some administrative domain, or it may
possibly be globally unique.
A router implementation selects a Router Identifier according to a
configured policy that defines the uniqueness scope. Thus, an
implementation MAY be configured to choose an IPv4 unicast address
assigned to the router as the Router Identifier, but the
implementation MUST allow the identifier to be configured manually.
Protocols such as BGP [RFC4271] and OSPFv2 [RFC2328] are other
protocols that make use of 32 bit identifiers for routers. Provided
that the stability and uniqueness requirements of the protocols that
make use of the Router Identifier are met, an implementation MAY use
the same identifier as is used by other protocols.
END
Section 3 Definition of Router Identifier
ADD
The field MUST contain a valid Router Identifier or the value zero.
END
Section 7.2
OLD
[RFC1213] McCloghrie, K. and M. Rose, "Management Information Base
for Network Management of TCP/IP-based internets:MIB-II",
STD 17, RFC 1213, March 1991.
[RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, April 1998.
NEW
[RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, April 1998.
[RFC2863] McCloghrie, K. and Kastenholz, F., "The Interfaces Group
MIB", RFC 2863, June 2000.
END