RFC 2012
SNMPv2 Management Information Base for the Transmission Control Protocol using SMIv2
RFC 2012 💖 SNMPv2 MIB for TCP (using SMIv2)
okay bestie, this one is the SNMPv2 Management Information Base for the Transmission Control Protocol using SMIv2 🎀. It was written by K. McCloghrie as Editor, from Cisco Systems, and it's dated November 1996. It's a Standards Track doc, and it updates RFC 1213 🦋. No obsoletes here, so it's not replacing anything, just building on 1213 ✨.
Status of This Memo 📜
this doc specifies an Internet standards track protocol for the Internet community, and it's asking for discussion and suggestions for improvements 🫶. for the standardization state and status of this protocol, check the current edition of the "Internet Official Protocol Standards" (STD 1) 💅. distribution of this memo is unlimited 🌈.
IESG Note 🚨 the IP, UDP, and TCP MIB modules only support IPv4 right now 🙈. these three modules use the IpAddress type, which is defined as an OCTET STRING of length 4, to represent the IPv4 32-bit internet addresses. (See RFC 1902, SMI for SNMPv2.) they don't support the new 128-bit IPv6 internet addresses 💀.
Table of Contents 🗂️
1. Introduction ................................................ 1
2. Definitions ................................................. 2
2.1 The TCP Group .............................................. 3
2.2 Conformance Information .................................... 8
2.2.1 Compliance Statements .................................... 8
2.2.2 Units of Conformance ..................................... 9
3. Acknowledgements ............................................ 10
4. References .................................................. 10
5. Security Considerations ..................................... 10
6. Editor's Address ............................................ 101. Introduction ✨
okay so picture a management system 🧚. it has several (potentially many!) nodes, and each one has a processing entity called an agent that can access management instrumentation 🔧. then there's at least one management station, plus a management protocol that carries management information between the agents and the stations 💌. everything runs under an administrative framework that defines authentication, authorization, access control, and privacy policies 🔐. that framework is giving main character energy fr.
management stations run management applications that monitor and control managed elements 👑. managed elements are devices like hosts, routers, terminal servers, etc., and they're monitored and controlled through access to their management information.
the management information is seen as a collection of managed objects, living in a virtual information store called the Management Information Base (MIB) 🗃️. related objects are grouped into MIB modules, which are written using a subset of OSI's Abstract Syntax Notation One (ASN.1) [1], termed the Structure of Management Information (SMI) [2] 🍓.
this doc is the MIB module that defines managed objects for managing implementations of the Transmission Control Protocol (TCP) [3] 🦋.
the managed objects in this MIB module were originally defined with the SNMPv1 framework as part of MIB-II [4] 🌸. this doc defines the same objects for TCP using the SNMPv2 framework, so it's the same vibe, just upgraded 🔥.
2. Definitions 💅
the module starts out like this:
TCP-MIB DEFINITIONS ::= BEGIN
IMPORTS
MODULE-IDENTITY, OBJECT-TYPE, Integer32, Gauge32,
Counter32, IpAddress, mib-2 FROM SNMPv2-SMI
MODULE-COMPLIANCE, OBJECT-GROUP FROM SNMPv2-CONF;
tcpMIB MODULE-IDENTITY
LAST-UPDATED "9411010000Z"
ORGANIZATION "IETF SNMPv2 Working Group"
CONTACT-INFO
" Keith McCloghrie
Postal: Cisco Systems, Inc.
170 West Tasman Drive
San Jose, CA 95134-1706
US
Phone: +1 408 526 5260
Email: kzm@cisco.com"
DESCRIPTION
"The MIB module for managing TCP implementations."
REVISION "9103310000Z"
DESCRIPTION
"The initial revision of this MIB module was part of MIB-
II."
::= { mib-2 49 }2.1. The TCP Group 🌷
-- the TCP group
tcp OBJECT IDENTIFIER ::= { mib-2 6 }
tcpRtoAlgorithm OBJECT-TYPE
SYNTAX INTEGER {
other(1), -- none of the following
constant(2), -- a constant rto
rsre(3), -- MIL-STD-1778, Appendix B
vanj(4) -- Van Jacobson's algorithm [5]
}
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The algorithm used to determine the timeout value used for
retransmitting unacknowledged octets."
::= { tcp 1 }
tcpRtoMin OBJECT-TYPE
SYNTAX Integer32
UNITS "milliseconds"
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The minimum value permitted by a TCP implementation for the
retransmission timeout, measured in milliseconds. More
refined semantics for objects of this type depend upon the
algorithm used to determine the retransmission timeout. In
particular, when the timeout algorithm is rsre(3), an object
of this type has the semantics of the LBOUND quantity
described in RFC 793."
::= { tcp 2 }
tcpRtoMax OBJECT-TYPE
SYNTAX Integer32
UNITS "milliseconds"
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The maximum value permitted by a TCP implementation for the
retransmission timeout, measured in milliseconds. More
refined semantics for objects of this type depend upon the
algorithm used to determine the retransmission timeout. In
particular, when the timeout algorithm is rsre(3), an object
of this type has the semantics of the UBOUND quantity
described in RFC 793."
::= { tcp 3 }
tcpMaxConn OBJECT-TYPE
SYNTAX Integer32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The limit on the total number of TCP connections the entity
can support. In entities where the maximum number of
connections is dynamic, this object should contain the value
-1."
::= { tcp 4 }
tcpActiveOpens OBJECT-TYPE
SYNTAX Counter32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The number of times TCP connections have made a direct
transition to the SYN-SENT state from the CLOSED state."
::= { tcp 5 }
tcpPassiveOpens OBJECT-TYPE
SYNTAX Counter32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The number of times TCP connections have made a direct
transition to the SYN-RCVD state from the LISTEN state."
::= { tcp 6 }
tcpAttemptFails OBJECT-TYPE
SYNTAX Counter32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The number of times TCP connections have made a direct
transition to the CLOSED state from either the SYN-SENT
state or the SYN-RCVD state, plus the number of times TCP
connections have made a direct transition to the LISTEN
state from the SYN-RCVD state."
::= { tcp 7 }
tcpEstabResets OBJECT-TYPE
SYNTAX Counter32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The number of times TCP connections have made a direct
transition to the CLOSED state from either the ESTABLISHED
state or the CLOSE-WAIT state."
::= { tcp 8 }
tcpCurrEstab OBJECT-TYPE
SYNTAX Gauge32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The number of TCP connections for which the current state
is either ESTABLISHED or CLOSE- WAIT."
::= { tcp 9 }
tcpInSegs OBJECT-TYPE
SYNTAX Counter32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The total number of segments received, including those
received in error. This count includes segments received on
currently established connections."
::= { tcp 10 }
tcpOutSegs OBJECT-TYPE
SYNTAX Counter32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The total number of segments sent, including those on
current connections but excluding those containing only
retransmitted octets."
::= { tcp 11 }
tcpRetransSegs OBJECT-TYPE
SYNTAX Counter32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The total number of segments retransmitted - that is, the
number of TCP segments transmitted containing one or more
previously transmitted octets."
::= { tcp 12 }
-- the TCP Connection table
-- The TCP connection table contains information about this
-- entity's existing TCP connections.
tcpConnTable OBJECT-TYPE
SYNTAX SEQUENCE OF TcpConnEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"A table containing TCP connection-specific information."
::= { tcp 13 }
tcpConnEntry OBJECT-TYPE
SYNTAX TcpConnEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"A conceptual row of the tcpConnTable containing information
about a particular current TCP connection. Each row of this
table is transient, in that it ceases to exist when (or soon
after) the connection makes the transition to the CLOSED
state."
INDEX { tcpConnLocalAddress,
tcpConnLocalPort,
tcpConnRemAddress,
tcpConnRemPort }
::= { tcpConnTable 1 }
TcpConnEntry ::= SEQUENCE {
tcpConnState INTEGER,
tcpConnLocalAddress IpAddress,
tcpConnLocalPort INTEGER,
tcpConnRemAddress IpAddress,
tcpConnRemPort INTEGER
}
tcpConnState OBJECT-TYPE
SYNTAX INTEGER {
closed(1),
listen(2),
synSent(3),
synReceived(4),
established(5),
finWait1(6),
finWait2(7),
closeWait(8),
lastAck(9),
closing(10),
timeWait(11),
deleteTCB(12)
}
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"The state of this TCP connection.
The only value which may be set by a management station is
deleteTCB(12). Accordingly, it is appropriate for an agent
to return a `badValue' response if a management station
attempts to set this object to any other value.
If a management station sets this object to the value
deleteTCB(12), then this has the effect of deleting the TCB
(as defined in RFC 793) of the corresponding connection on
the managed node, resulting in immediate termination of the
connection.
As an implementation-specific option, a RST segment may be
sent from the managed node to the other TCP endpoint (note
however that RST segments are not sent reliably)."
::= { tcpConnEntry 1 }
tcpConnLocalAddress OBJECT-TYPE
SYNTAX IpAddress
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The local IP address for this TCP connection. In the case
of a connection in the listen state which is willing to
accept connections for any IP interface associated with the
node, the value 0.0.0.0 is used."
::= { tcpConnEntry 2 }tcpConnLocalPort OBJECT-TYPE is up next, and it's the local port number for each TCP connection 🎀 Here's the MIB module from there to the end:
tcpConnLocalPort OBJECT-TYPE
SYNTAX INTEGER (0..65535)
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The local port number for this TCP connection."
::= { tcpConnEntry 3 }
tcpConnRemAddress OBJECT-TYPE
SYNTAX IpAddress
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The remote IP address for this TCP connection."
::= { tcpConnEntry 4 }
tcpConnRemPort OBJECT-TYPE
SYNTAX INTEGER (0..65535)
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The remote port number for this TCP connection."
::= { tcpConnEntry 5 }
tcpInErrs OBJECT-TYPE
SYNTAX Counter32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The total number of segments received in error (e.g., bad
TCP checksums)."
::= { tcp 14 }
tcpOutRsts OBJECT-TYPE
SYNTAX Counter32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The number of TCP segments sent containing the RST flag."
::= { tcp 15 }
-- conformance information
tcpMIBConformance OBJECT IDENTIFIER ::= { tcpMIB 2 }
tcpMIBCompliances OBJECT IDENTIFIER ::= { tcpMIBConformance 1 }
tcpMIBGroups OBJECT IDENTIFIER ::= { tcpMIBConformance 2 }
-- compliance statements
tcpMIBCompliance MODULE-COMPLIANCE
STATUS current
DESCRIPTION
"The compliance statement for SNMPv2 entities which
implement TCP."
MODULE -- this module
MANDATORY-GROUPS { tcpGroup
}
::= { tcpMIBCompliances 1 }
-- units of conformance
tcpGroup OBJECT-GROUP
OBJECTS { tcpRtoAlgorithm, tcpRtoMin, tcpRtoMax,
tcpMaxConn, tcpActiveOpens,
tcpPassiveOpens, tcpAttemptFails,
tcpEstabResets, tcpCurrEstab, tcpInSegs,
tcpOutSegs, tcpRetransSegs, tcpConnState,
tcpConnLocalAddress, tcpConnLocalPort,
tcpConnRemAddress, tcpConnRemPort,
tcpInErrs, tcpOutRsts }
STATUS current
DESCRIPTION
"The tcp group of objects providing for management of TCP
entities."
::= { tcpMIBGroups 1 }
END3. Acknowledgements ✨
This document contains a modified subset of RFC 1213. 💖
4. References 📚
[1] Information processing systems - Open Systems Interconnection - Specification of Abstract Syntax Notation One (ASN.1), International Organization for Standardization. International Standard 8824, (December, 1987).
[2] McCloghrie, K., Editor, "Structure of Management Information for version 2 of the Simple Network Management Protocol (SNMPv2)", RFC 1902, Cisco Systems, January 1996.
[3] Postel, J., "Transmission Control Protocol - DARPA Internet Program Protocol Specification", STD 7, RFC 793, DARPA, September 1981.
[4] McCloghrie, K., and M. Rose, "Management Information Base for Network Management of TCP/IP-based internets: MIB-II", STD 17, RFC 1213, March 1991.
[5] Jacobson, V., "Congestion Avoidance and Control", SIGCOMM 1988, Stanford, California.
5. Security Considerations 🙈
Security issues are not discussed in this memo.
6. Editor's Address 💌
Keith McCloghrie
Cisco Systems, Inc.
170 West Tasman Drive
San Jose, CA 95134-1706
US
Phone: +1 408 526 5260
EMail: kzm@cisco.comThat's the whole thing, bestie! 🦋 Super proud of you for getting through both parts 🫶
📦 where this page comes from
- ietf: rfc2012 1996-11
- 💖 girlified by claude-haiku-5-5 on : a language model's rewrite of the original, under its terms