📄 rfc1608.txt
字号:
directly by routers for dynamic routing. However, it certainly can
be used in network management systems to determine the allowed paths
[i.e., in accordance with published policies] between two networks.
This will be useful in finding alternate paths, and evaluating the
connectivity of networks.
3. Number assignment information
In the following, Directory objects have been defined to represent IP
and AS (Autonomous System) namespace in the Directory. Their purpose
is to provide
o mapping from IP number to IP network element (network or node)
o mapping from IP number to AS number and vice versa
o assignment and delegation information
Johannsen, Mansfield, Kosters & Sataluri [Page 7]
RFC 1608 IP Information in the X.500 Directory March 1994
The need for a global, distributed database supporting the objectives
arises mainly from distributed IP- and AS-number assignment.
Describing all IP numbers with one of the new objects delegatedBlock,
ipGroup and ipReference leads to the desired information. AS number
information is stored with the objects asBlock and asReference.
Furthermore, all assigned numbers have some properties in common.
Therefore, an objectclass assignedNumberClass is introduced. This
class exports attributes to delegatedBlock, ipGroup, ipReference,
asBlock, and asReference.
AssignedNumberClass is defined as follows ("number" always refers to
IP number of delegatedBlock, network, host, and AS number, resp.):
assignedNumberClass OBJECT CLASS
SUBCLASS of top
MAY CONTAIN
assBy :: DistinguishedNameSyntax,
/* refers to an organization or organizationalRole
that assigned the number to assTo (see below) */
assTo :: DistinguishedNameSyntax,
/* refers to organization or organizationalRole
that the number was assigned to. This does not
imply that assTo "owns" this number now. */
assDate :: uTCTimeSyntax,
/* date of assignment for this number */
nicHandle :: CaseIgnoreStringSyntax,
/* gives the unique ID for a description
related to this number.
format: "handle : nic-domain-name"
example: MAK21 : rs.internic.net */
relNwElement :: DistinguishedNameSyntax,
/* the network element related to this number
(network or node) */
3.1 Delegated Block object
This object provides information on a block of IP addresses delegated
to some local-authority or service provider. Only contiguous blocks
can be represented with the following schema. If an organization
(say, a NIC) has been assigned several IP network numbers which do
not form a contiguous block, it might want to use a different form of
representing that fact (e.g., using imageNetworks). The
delegatedBlock object holds lower and upper bounds of the block.
Note that the above does not make any assumption about the network
masks being constrained by byte boundaries. We can thus represent
subnetting within a "network (number)" that often happens within an
Johannsen, Mansfield, Kosters & Sataluri [Page 8]
RFC 1608 IP Information in the X.500 Directory March 1994
organization in the same framework.
This schema does lead to some granularity in the otherwise flat IP-
number space. Further, the granularity is significant as it may be
used to identify the administrator of the block - a service provider
or a domain manager. E.g., it fits well into the schema of
aggregating networks for routing purposes as has been proposed in
[4].
The object delegatedBlock is of the form:
delegatedBlock OBJECT CLASS
SUBCLASS of AssignedNumberClass
MUST CONTAIN
delegatedBlockName :: caseIgnoreStringSyntax,
lowerBound :: IPStringSyntax,
/* smallest IP address belonging to the
block, e.g. 195.100.0.0 */
upperBound :: IPStringSyntax
/* highest IP address belonging to the
block, e.g. 195.103.255.255 */
The attribute relNwElement (inherited from AssignedNumberClass) can
point to a networkImage covering all networks within the block if
this makes sense.
3.2 IP Group object
This object provides information for an IP network number. Its
purpose is basically only to
o show that the number has been assigned, and
o provide a reference to the descriptive ipNetworkObject for
this network.
Regardless of the actual value of x, IP group objects may exist for
IP numbers x.0.0.0, x.y.0.0 and x.y.z.0. This approach includes
"classical" class-A, -B and -C network addresses as well as any kind
of super- and subnetworking.
The IP group object is a subclass of assignedNumberClass. The
attribute relNwElement points to an ipNetworkImage as defined above.
ipGroup OBJECT CLASS
SUBCLASS of AssignedNumberClass
MUST CONTAIN
ipGroupName :: IPStringSyntax,
/* IP number; x.0.0.0 or x.y.0.0 or x.y.z.0
Johannsen, Mansfield, Kosters & Sataluri [Page 9]
RFC 1608 IP Information in the X.500 Directory March 1994
where x, y, z in 1..255 */
ipNwMask :: IPStringSyntax
/* mask that applies to all numbers
within the group; used to define
classless networking; */
3.3 IP Reference object
There is one IP reference object for each IP host address. The
purpose of this object is to
o tell that this IP number is already assigned to a node
o give a pointer to the related ipNodeImageObject
The IP reference object is a subclass of assignedNumberClass. The
attribute relNwElement points to an ipNodeImage.
ipReference OBJECT CLASS
SUBCLASS of AssignedNumberClass
MUST CONTAIN
ipReferenceName :: IPString
/* value is always IP address */
3.4 AS block object
The AS block object is used to show delegation of blocks of AS
numbers to regional registries. This is similar to delegatedBlock of
ipNetwork numbers.
asBlock OBJECT CLASS
SUBCLASS of AssignedNumberClass
MUST CONTAIN
asBlockName :: caseIgnoreStringSyntax,
asLowerBound :: integerStringSyntax,
asUpperBound :: integerStringSyntax
An AS block will comprise several consecutive AS numbers. Objects to
describe these numbers may be stored in asObjects.
3.5 AS reference object
An AS reference object is used to show that an Autonomous System
number has been assigned (and thus can not be given to somebody
else). Similar to ipGroup, asReference does not contain technical
details about an autonomous system itself but rather points (with
relNwElement) to a descriptive asObject.
Johannsen, Mansfield, Kosters & Sataluri [Page 10]
RFC 1608 IP Information in the X.500 Directory March 1994
asReference OBJECT CLASS
SUBCLASS of AssignedNumberClass
MUST CONTAIN
asNumber :: integerStringSyntax
4. Directory tree
root
|
+-------------+---------------+
| |
c= o=Internet
| |
+-----+------+ +------+-------+
| | | |
ipNw= as= dbl= asB=
| | |
ipNd= ipG= asRef=
| |
ipNwIf= ipRef=
Figure 1: Overall relationship of objects.
4.1 IP image objects
According to [1], IP image entries will be stored underneath the
organization / organizationalUnit entry of the entity responsible for
that network. The case that such an entry does not yet exist in the
white-pages pilot is discussed in 4.4 below.
4.2 AS objects
The technical and administrative description of an AS is basically
maintained by NICs, network providers, or other special
organizations. It is suggested that these organizations build a
subtree for information on AS which they are responsible for.
4.3 Namespace objects
The new IP namespace objects build a single tree in the Directory. It
is suggested that this tree will have a root of type
organizationalUnit within @o=Internet@ou=Network Information.
objectClass= organizationalUnit
organizationalUnitName= IP networks
description= root of IP number tree
Johannsen, Mansfield, Kosters & Sataluri [Page 11]
RFC 1608 IP Information in the X.500 Directory March 1994
The tree is built under an administrative and an implementational
view. Nowadays, network numbers usually are assigned to
organizations by (national) Network Information Centers (NIC) which
themselves have got a block of IP network numbers assigned from
another authority (e.g., IR at top level). This concept of delegated
blocks falling apart in smaller delegated blocks and IP network
numbers is used to model the Directory tree. Thus, an ipGroup object
is always subordinate of a delegated block object (namely the
delegated block including this IP number). Network numbers that were
directly assigned by a top-level authority, i.e., have not been
object of a delegation to a local assigning authority, will all be at
one level in the Directory. Already today, however, we find many
delegations within the traditional class A-, B- and C-addresses.
Such a delegation is represented by a delegated block object, having
the assigned IP network numbers as subordinates. Also, part of the
block can be further delegated to another authority, leading to
another delegated block object within the parent delegated block's
tree. Usually, subordinates of ipGroup objects are ipReferences,
i.e., single IP addresses as assigned to nodes. To support
subnetworking, it is also allowed to divide ipGroups into several
subnetwork ipGroups, each representing an IP subnetwork. In such
cases, subnetwork numbers are given as subordinates to the assigned
IP network number. Network masks clarify what the subnetwork
addresses are.
ou=IP networks
|
+-------------------+-----------------------+
/ | \
dbl=150.0.0.0-150.100.0.0
|
+-------------------+-----------------------+
/ | \
ipG=150.80.0.0
|
+-------------------+-----------------------+
/ | \
ipG=150.80.240.0
|
+-------------------+-----------------------+
/ | \
ipRef=150.80.254.1 ipRef=150.80.254.2 ipRef=150.80.254.3
Figure 2: Example population of IP namespace tree according
to delegation and subnetworking.
For some applications, the separation of ipImage (description of the
network) and ipGroup (description of the namespace element) will bear
Johannsen, Mansfield, Kosters & Sataluri [Page 12]
RFC 1608 IP Information in the X.500 Directory March 1994
disadvantages in the look-up procedure. In that case one might think
of combining both object classes with the aim to provide one object
describing administrative and technical data for an IP network.
As Autonomous Systems are an additional namespace to the existing IP
number space, they should go into a separate subtree. It is suggested
that this is an organizationalUnit within @o=Internet@ou=Network
Information.
objectClass= organizationalUnit
organizationalUnitName= AS numbers
description= root of Autonomous System number space
Similar to blocks of IP network numbers, blocks of AS numbers are
sometimes delegated to another registry. This is expressed by asBlock
objects. These objects come below the root of the AS number space.
All AS numbers falling into such a block are stored as subordinates
of the block. An AS block may have smaller AS blocks underneath if
delegation is extended.
4.4 Relationship to organizational entries
Organizational information (i.e., white-pages-like information about
an organization, its departments and employees) occurs at several
places in the network DIT - [org of IP-Number, org of AS-Number, org
of Admin- contact, However, it will be basically mastered
[administered, maintained] by the organization itself in the
Directory Management Domain (DMD) over which the organization has the
authority. This gives rise to some tricky problems - a typical
example is that of a NIC which holds the AS, DNS, IP, ... subtrees
of the DIT.
A good strategy would avoid explicit duplication of information. By
explicit duplication of information we understand information being
duplicated outside the directory framework, e.g., by having several
master entries for one and the same piece of information. The only
way to avoid duplication would be to have relevant entries point to
the pertinent organizational entry for organizational information.
But since
o most organizations do not, as yet, have an entry in the DIT and
o the reliability of the access to an organizations DIT when
stored in a remote DSA cannot be taken for granted,
the following framework is adopted to accommodate the conflicting
requirements /conditions.
Johannsen, Mansfield, Kosters & Sataluri [Page 13]
RFC 1608 IP Information in the X.500 Directory March 1994
o A copy of all the necessary organization-info is retained
at the NICs DSA. Since only the necessary info will be kept
the NIC will not be burdened to act as the repository of the
organizations DIT. These objects may be kept in a separate
subtree of affiliated-organizations [organizations
affiliated to the NIC]. Though the affiliated organizations node
does not really represent a locality, it is suggested to define
the node as objectClass locality. This does not break the
Directory schema when entries of organizations shall become
subordinate to the NICs organization's entry.
o The problem of information duplication/consistency will arise when
organizational DITs/DSAs do come into existence. At that stage a
shadowing mechanism which will attempt to maintain the data
consistency may be resorted to. The X.500/ISO 9594(1993)
implementations are expected to provide appropriate shadowing
⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -