rfc1354.txt
来自「RFC 的详细文档！」· 文本 代码 · 共 675 行 · 第 1/2 页
TXT
675 行
Network Working Group F. Baker
Request For Comments: 1354 ACC
July 1992
IP Forwarding Table MIB
Status of this Memo
This RFC specifies an IAB standards track protocol for the Internet
community, and requests discussion and suggestions for improvements.
Please refer to the current edition of the "IAB Official Protocol
Standards" for the standardization state and status of this protocol.
Distribution of this memo is unlimited.
Abstract
This memo defines a portion of the Management Information Base (MIB)
for use with network management protocols in TCP/IP-based internets.
In particular, it defines objects for managing routes in the IP
Internet.
It is proposed that the ipRouteTable defined by MIB-II (RFC 1213) be
deprecated and replaced with this table. This adds the ability to
set or display multi-path routes, and varying routes by network
management policy.
Table of Contents
1. The Network Management Framework ............................ 1
2. Objects ..................................................... 2
2.1 Format of Definitions ...................................... 2
3. Overview .................................................... 3
3.1 Structure of MIB ........................................... 3
4. Definitions ................................................. 4
4.1 IP Forwarding Table ........................................ 4
5. Acknowledgements ............................................ 11
6. References .................................................. 11
7. Security Considerations........................................ 12
8. Author's Address............................................... 12
1. The Network Management Framework
The Internet-standard Network Management Framework consists of three
components. They are:
RFC 1155 which defines the SMI, the mechanisms used for describing
and naming objects for the purpose of management. RFC 1212 defines a
Baker [Page 1]
RFC 1354 IP Forwarding Table MIB July 1992
more concise description mechanism, which is wholly consistent with
the SMI.
RFC 1156 which defines MIB-I, the core set of managed objects for the
Internet suite of protocols. RFC 1213 defines MIB-II, an evolution
of MIB-I based on implementation experience and new operational
requirements.
RFC 1157 which defines the SNMP, the protocol used for network access
to managed objects.
The Framework permits new objects to be defined for the purpose of
experimentation and evaluation.
2. Objects
Managed objects are accessed via a virtual information store, termed
the Management Information Base or MIB. Objects in the MIB are
defined using the subset of Abstract Syntax Notation One (ASN.1) [7]
defined in the SMI. In particular, each object has a name, a syntax,
and an encoding. The name is an object identifier, an
administratively assigned name, which specifies an object type. The
object type together with an object instance serves to uniquely
identify a specific instantiation of the object. For human
convenience, we often use a textual string, termed the OBJECT
DESCRIPTOR, to also refer to the object type.
The syntax of an object type defines the abstract data structure
corresponding to that object type. The ASN.1 language is used for
this purpose. However, the SMI [3] purposely restricts the ASN.1
constructs which may be used. These restrictions are explicitly made
for simplicity.
The encoding of an object type is simply how that object type is
represented using the object type's syntax. Implicitly tied to the
notion of an object type's syntax and encoding is how the object type
is represented when being transmitted on the network.
The SMI specifies the use of the basic encoding rules of ASN.1 [8],
subject to the additional requirements imposed by the SNMP.
2.1. Format of Definitions
Section 4 contains contains the specification of all object types
contained in this MIB module. The object types are defined using the
conventions defined in the SMI, as amended by the extensions
specified in [9].
Baker [Page 2]
RFC 1354 IP Forwarding Table MIB July 1992
3. Overview
3.1. Structure of MIB
The IP Forwarding Table is quite analogous to the older ipRoute
Table. The principal differences are:
(1) It is somewhat re-organized, for aesthetic reasons,
(2) It has the Next Hop Autonomous System Number, useful
primarily to the administrators of regional networks,
(3) It is instanced by Policy and Next Hop as well as by
ultimate destination. Thus, multiple multipath routes
can be managed, not just a single route, along with the
circumstances under which the any given route might be
chosen.
4. Definitions
RFC1354-MIB DEFINITIONS ::= BEGIN
IMPORTS
Gauge, IpAddress
FROM RFC1155-SMI
mib-2, ip
FROM RFC1213-MIB
OBJECT-TYPE
FROM RFC-1212;
-- This MIB module uses the extended OBJECT-TYPE macro as
-- defined in [9].
ipForward OBJECT IDENTIFIER ::= { ip 24 }
ipForwardNumber OBJECT-TYPE
SYNTAX Gauge
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of current ipForwardTable entries
that are not invalid."
::= { ipForward 1 }
-- IP Forwarding Table
-- The IP Forwarding Table obsoletes and replaces the ipRoute
-- Table current in MIB-I and MIB-II. It adds knowledge of
Baker [Page 3]
RFC 1354 IP Forwarding Table MIB July 1992
-- the autonomous system of the next hop, multiple next hop
-- support, and policy routing support.
ipForwardTable OBJECT-TYPE
SYNTAX SEQUENCE OF IpForwardEntry
ACCESS not-accessible
STATUS mandatory
DESCRIPTION
"This entity's IP Routing table."
REFERENCE
"RFC 1213 Section 6.6, The IP Group"
::= { ipForward 2 }
ipForwardEntry OBJECT-TYPE
SYNTAX IpForwardEntry
ACCESS not-accessible
STATUS mandatory
DESCRIPTION
"A particular route to a particular destina-
tion, under a particular policy."
INDEX {
ipForwardDest,
ipForwardProto,
ipForwardPolicy,
ipForwardNextHop
}
::= { ipForwardTable 1 }
IpForwardEntry ::=
SEQUENCE {
ipForwardDest
IpAddress,
ipForwardMask
IpAddress,
ipForwardPolicy
INTEGER,
ipForwardNextHop
IpAddress,
ipForwardIfIndex
INTEGER,
ipForwardType
INTEGER,
ipForwardProto
INTEGER,
ipForwardAge
Baker [Page 4]
RFC 1354 IP Forwarding Table MIB July 1992
INTEGER,
ipForwardInfo
OBJECT IDENTIFIER,
ipForwardNextHopAS
INTEGER,
ipForwardMetric1
INTEGER,
ipForwardMetric2
INTEGER,
ipForwardMetric3
INTEGER,
ipForwardMetric4
INTEGER,
ipForwardMetric5
INTEGER
}
ipForwardDest OBJECT-TYPE
SYNTAX IpAddress
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The destination IP address of this route. An
entry with a value of 0.0.0.0 is considered a
default route.
This object may not take a Multicast (Class D)
address value.
Any assignment (implicit or otherwise) of an
instance of this object to a value x must be
rejected if the bitwise logical-AND of x with
the value of the corresponding instance of the
ipForwardMask object is not equal to x."
::= { ipForwardEntry 1 }
ipForwardMask OBJECT-TYPE
SYNTAX IpAddress
ACCESS read-write
STATUS mandatory
DESCRIPTION
"Indicate the mask to be logical-ANDed with the
destination address before being compared to
the value in the ipForwardDest field. For
those systems that do not support arbitrary
subnet masks, an agent constructs the value of
the ipForwardMask by reference to the IP Ad-
Baker [Page 5]
RFC 1354 IP Forwarding Table MIB July 1992
dress Class.
Any assignment (implicit or otherwise) of an
instance of this object to a value x must be
rejected if the bitwise logical-AND of x with
the value of the corresponding instance of the
ipForwardDest object is not equal to ipForward-
Dest."
DEFVAL { '00000000'h } -- 0.0.0.0
::= { ipForwardEntry 2 }
-- The following convention is included for specification
-- of TOS Field contents. At this time, the Host Requirements
-- and the Router Requirements documents disagree on the width
-- of the TOS field. This mapping describes the Router
-- Requirements mapping, and leaves room to widen the TOS field
-- without impact to fielded systems.
ipForwardPolicy OBJECT-TYPE
SYNTAX INTEGER
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The general set of conditions that would cause
the selection of one multipath route (set of
next hops for a given destination) is referred
to as 'policy'.
Unless the mechanism indicated by ipForwardPro-
to specifies otherwise, the policy specifier is
the IP TOS Field. The encoding of IP TOS is as
specified by the following convention. Zero
indicates the default path if no more specific
policy applies.
+-----+-----+-----+-----+-----+-----+-----+-----+
| | | |
| PRECEDENCE | TYPE OF SERVICE | 0 |
| | | |
+-----+-----+-----+-----+-----+-----+-----+-----+
IP TOS IP TOS
Field Policy Field Policy
Contents Code Contents Code
0 0 0 0 ==> 0 0 0 0 1 ==> 2
0 0 1 0 ==> 4 0 0 1 1 ==> 6
0 1 0 0 ==> 8 0 1 0 1 ==> 10
Baker [Page 6]
⌨️ 快捷键说明
复制代码Ctrl + C
搜索代码Ctrl + F
全屏模式F11
增大字号Ctrl + =
减小字号Ctrl + -
显示快捷键?