RFC 1749 HISTORIC MANAGEMENT · TOKEN RING · MIB
802.5 SSR MIB: IEEE 802.5 Station Source Routing MIB using SMIv2
SNMP objects for reading and managing the Token Ring source routes an end station has learned.
RFC EDITOR
McCloghrie, K., Baker, F., and E. Decker, "IEEE 802.5 Station Source Routing MIB using SMIv2", RFC 1749, DOI 10.17487/RFC1749, December 1994, <https://www.rfc-editor.org/info/rfc1749>.
BIBTEX
@misc{rfc1749,
series = {Request for Comments},
number = 1749,
howpublished = {RFC 1749},
publisher = {RFC Editor},
doi = {10.17487/RFC1749},
url = {https://www.rfc-editor.org/info/rfc1749},
author = {K. McCloghrie and F. Baker and E. Decker},
title = {{IEEE 802.5 Station Source Routing MIB using SMIv2}},
pagetotal = 10,
year = 1994,
month = dec,
} LINEAGE · FROM THE RFC INDEXOpen full graph →
RFC text
Contents
Network Working Group K. McCloghrie
Request for Comments: 1749 F. Baker
Updates: 1748 E. Decker
Category: Standards Track cisco Systems, Inc.
December 1994
IEEE 802.5 Station Source Routing MIB using SMIv2
Status of this Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Table of Contents
1. Introduction ............................................. 1
2. The SNMPv2 Network Management Framework .................. 2
2.1 Object Definitions ...................................... 2
3. Overview ................................................. 2
3.1 Source Routing .......................................... 2
3.2 Relationship to RFC 1748 ................................ 3
3.3 Relationship to RFC 1525 ................................ 3
3.4 Static Source Routes .................................... 4
3.5 Destinations on the Local Ring .......................... 4
4. Definitions .............................................. 4
5. Acknowledgements ......................................... 8
6. References ............................................... 8
7. Security Considerations .................................. 9
8. Authors' Addresses ....................................... 10
1. Introduction
This memo defines a portion of the Management Information Base (MIB)
for use with network management protocols in the Internet community.
In particular, it describes managed objects used by IEEE 802.5 end-
stations for managing source routes on a Token Ring network where
IEEE source-routing is in use. IEEE source-routing is described in
802.5 Token Ring Access Method and Physical Layer Specifications [8]
and related ISO publications [9, 10, 11].
This memo is an incremental update to RFC 1748 [6]. It is documented
separately from the RFC 1748 solely due to the latter's maturity
within the Internet standardization process.
2. The SNMPv2 Network Management Framework
The SNMPv2 Network Management Framework consists of four major
components. They are:
o RFC 1442 [1] which defines the SMI, the mechanisms used for
describing and naming objects for the purpose of management.
o STD 17, RFC 1213 [2] defines MIB-II, the core set of managed
objects for the Internet suite of protocols.
o RFC 1445 [3] which defines the administrative and other
architectural aspects of the framework.
o RFC 1448 [4] which defines the protocol used for network
access to managed objects.
The Framework permits new objects to be defined for the purpose of
experimentation and evaluation.
2.1. Object Definitions
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)
defined in the SMI. In particular, each object type is named by an
OBJECT IDENTIFIER, an administratively assigned name. 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 descriptor, to refer to the
object type.
3. Overview
This memo defines a single table: the 802.5 Station Source Routing
Table, which contains the source routes known by a end-station on an
IEEE 802.5 Token Ring network in which IEEE source-routing is in use.
3.1. Source Routing
Source routing extends the 802.5 protocol [8] by assigning a unique
ring number to each ring within the extended LAN, and a bridge number
to each source routing bridge's connection to a ring. A Routing
Information Field (RIF) must be included in frames which need to
traverse multiple rings. The format of the RIF is:
octets octets octets octets
1&2 3&4 5&6 17&18
+------+------+------+-------+------+
| RC | RD | RD | ... | RD |
+------+------+------+-------+------+
<---- 0 to 8 RD fields ---->
The format of the Routing Control (RC) field is:
octet 1 octet 2
+---------------+---------------+
|b b b l l l l l|d f f f 0 0 0 0|
+---------------+---------------+
^ ^ ^ ^
| | | |
Explorer indicator --+ | | +-- Max frame length*
Length of RIF field --+ +-- Direction to use RDs
* Note that the length of the Maximum frame length subfield
has recently been extended to 6 bits.
The format of each Routing Descriptor (RD) field is:
octet 1 octet 2
+---------------+---------------+
|r r r r r r r r r r r r i i i i|
+---------------+---------------+
<---- ring number ----> <----->
^
|
bridge number --+
3.2. Relationship to RFC 1748
RFC 1748 [6], the IEEE 802.5 MIB, defines managed objects used for
interfaces to IEEE 802.5 Token Ring subnetworks. This memo is an
incremental update to RFC 1748, and is documented independently
solely due to the maturity of the definitions contained within RFC
1748.
3.3. Relationship to RFC 1525
RFC 1525 [7] defines the MIB objects specific to source-routing for
source-routing and SRT bridges. This memo defines the MIB objects
specific to source-routing for source-routing end-stations.
3.4. Static Source Routes
It is unclear how many, if any, existing systems allow the creation
or deletion of "static" 802.5 source routes by network management.
However, SNMPv2 SMI defines that the MAX-ACCESS clause as specifying
the maximal level of access which makes "protocol sense". Thus, this
memo provides support for static source routes through the
dot5SrRouteStatus object, but the conformance statements allow for
stations which do not support static source routes, by requiring that
compliant agents only need provide read-access to dot5SrRouteStatus.
3.5. Destinations on the Local Ring
Entries should be included in the dot5SrRouteTable for destination
MAC addresses which are on the same ring as the instrumented 802.5
interface. For such entries, dot5SrRouteDescr has the value of the
zero-length string, and dot5SrRouteControl has the corresponding
value.
4. Definitions
TOKENRING-STATION-SR-MIB DEFINITIONS ::= BEGIN
IMPORTS
MODULE-IDENTITY, OBJECT-TYPE
FROM SNMPv2-SMI
TEXTUAL-CONVENTION, RowStatus, MacAddress
FROM SNMPv2-TC
MODULE-COMPLIANCE, OBJECT-GROUP FROM SNMPv2-CONF
mib-2, ifIndex FROM RFC1213-MIB;
dot5SrMIB MODULE-IDENTITY
LAST-UPDATED "9412161000Z"
ORGANIZATION "IETF Interfaces MIB 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 source routes in
end-stations on IEEE 802.5 Token Ring networks."
::= { mib-2 42 }
dot5SrMIBObjects OBJECT IDENTIFIER ::= { dot5SrMIB 1 }
SourceRoute ::= TEXTUAL-CONVENTION
DISPLAY-HINT "1x:"
STATUS current
DESCRIPTION
"Represents a Source Route, containing an
embedded sequence of bridge and ring ID's,
as used by 802.5 Source Routing."
REFERENCE "Annex C of ISO/IEC 10038: 1993,
[ANSI/IEEE Std 802.1D, 1993]"
SYNTAX OCTET STRING (SIZE(0..30))
-- The 802.5 Station Source Route Table
--
dot5SrRouteTable OBJECT-TYPE
SYNTAX SEQUENCE OF Dot5SrRouteEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"The table of source-routing routes.
This represents the 802.5 RIF database."
::= { dot5SrMIBObjects 1 }
dot5SrRouteEntry OBJECT-TYPE
SYNTAX Dot5SrRouteEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"Information on a specific route.
An entry is created whenever a 'Single Path
Explorer' or an 'All Paths Explorer' discovers
a route to a neighbor not currently in the table,
or whenever an 'All Paths Explorer' discovers a
better (e.g., shorter) route than the route currently
stored in the table. This is done on behalf of
any network layer client.
The ifIndex value in the INDEX clause refers to
the value of MIB-II's ifIndex object for the
interface on which the route is in effect."
INDEX { ifIndex, dot5SrRouteDestination }
::= { dot5SrRouteTable 1 }
Dot5SrRouteEntry ::= SEQUENCE {
dot5SrRouteDestination MacAddress,
dot5SrRouteControl OCTET STRING,
dot5SrRouteDescr SourceRoute,
dot5SrRouteStatus RowStatus
}
dot5SrRouteDestination OBJECT-TYPE
SYNTAX MacAddress
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"The destination of this route."
::= { dot5SrRouteEntry 2 }
dot5SrRouteControl OBJECT-TYPE
SYNTAX OCTET STRING (SIZE(2))
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"The value of Routing Control field for this
route."
REFERENCE "Annex C of ISO/IEC 10038: 1993,
[ANSI/IEEE Std 802.1D, 1993]"
::= { dot5SrRouteEntry 3 }
dot5SrRouteDescr OBJECT-TYPE
SYNTAX SourceRoute
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"The embedded sequence of bridge and ring ID's
for this route. For destinations on the
local ring, the value of this object is
the zero-length string."
REFERENCE "Annex C of ISO/IEC 10038: 1993,
[ANSI/IEEE Std 802.1D, 1993]"
::= { dot5SrRouteEntry 4 }
dot5SrRouteStatus OBJECT-TYPE
SYNTAX RowStatus
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"The status of this row. Values of the instances
of dot5SrRouteControl and dot5SrRouteDescr can be
modified while the row's status is 'active."
::= { dot5SrRouteEntry 5 }
-- conformance information
dot5SrConformance OBJECT IDENTIFIER ::= { dot5SrMIB 2 }
dot5SrGroups OBJECT IDENTIFIER ::= { dot5SrConformance 1 }
dot5SrCompliances OBJECT IDENTIFIER ::= { dot5SrConformance 2 }
-- compliance statements
dot5SrCompliance MODULE-COMPLIANCE
STATUS current
DESCRIPTION
"The compliance statement for SNMPv2 entities
which implement the IEEE 802.5 Station Source Route
MIB."
MODULE -- this module
MANDATORY-GROUPS { dot5SrRouteGroup }
OBJECT dot5SrRouteStatus
SYNTAX INTEGER { active(1) } -- subset of values
MIN-ACCESS read-only
DESCRIPTION
"Write access is not required, and only the 'active'
value need be supported."
OBJECT dot5SrRouteControl
MIN-ACCESS read-only
DESCRIPTION
"Write access is not required."
OBJECT dot5SrRouteDescr
MIN-ACCESS read-only
DESCRIPTION
"Write access is not required."
::= { dot5SrCompliances 1 }
-- units of conformance
dot5SrRouteGroup OBJECT-GROUP
OBJECTS { dot5SrRouteControl,
dot5SrRouteDescr,
dot5SrRouteStatus
}
STATUS current
DESCRIPTION
"A collection of objects providing for the management of
source routes in stations on IEEE 802.5 source-routing
networks."
::= { dot5SrGroups 1 }
END
5. Acknowledgements
The need for this MIB module was agreed upon by the members of the
IETF Interfaces Working Group, and the definitions were derived from
experience with enterprise-specific MIBs presented to the Working
Group.
6. References
[1] Case, J., McCloghrie, K., Rose, M., and S. Waldbusser, "Structure
of Management Information for version 2 of the Simple Network
Management Protocol (SNMPv2)", RFC 1442, SNMP Research,Inc.,
Hughes LAN Systems, Dover Beach Consulting, Inc., Carnegie Mellon
University, April 1993.
[2] McCloghrie, K., and M. Rose, Editors, "Management Information
Base for Network Management of TCP/IP-based internets: MIB- II",
STD 17, RFC 1213, Hughes LAN Systems, Performance Systems
International, March 1991.
[3] Galvin, J., and K. McCloghrie, "Administrative Model for version
2 of the Simple Network Management Protocol (SNMPv2)", RFC 1445,
Trusted Information Systems, Hughes LAN Systems, April 1993.
[4] Case, J., McCloghrie, K., Rose, M., and S. Waldbusser, "Protocol
Operations for version 2 of the Simple Network Management
Protocol (SNMPv2)", RFC 1448, SNMP Research,Inc., Hughes LAN
Systems, Dover Beach Consulting, Inc., Carnegie Mellon
University, April 1993.
[5] Case, J., McCloghrie, K., Rose, M., and S. Waldbusser, "Textual
Conventions for version 2 of the Simple Network Management
Protocol (SNMPv2)", RFC 1443, SNMP Research Inc., Hughes LAN
Systems, Dover Beach Consulting, Inc., Carnegie Mellon
University, April 1993.
[6] McCloghrie, K., and E. Decker, "IEEE 802.5 Token Ring MIB using
SMIv2", RFC 1748 cisco Systems, Inc., December 1994.
[7] McCloghrie, K., Decker, E., Langville, P., and A. Rijsinghani,
"Definitions of Managed Objects for Source Routing Bridges", RFC
1525, Hughes LAN Systems, cisco Systems, Inc., Digital Equipment
Corporation, September 1993.
[8] "Token Ring Access Method and Physical Layer Specifications",
IEEE Standard 802.5-1989, 1989.
[9] "Information technology - Local and metropolitan area networks -
Part 5: Token ring access method and physical layer
specifications", ISO/IEC 8802-5, 1992.
[10] "Information technology - Telecommunications and information
exchange between systems - Local area networks - Media access
control (MAC) bridges", ISO/IEC 10038, 1993 [ANSI/IEEE Std
802.1D, 1993 Edition].
[11] "Source Routing Operation by End Systems", ISO/IEC 8802-2 PDAM5.3
(6N7721).
7. Security Considerations
Security issues are not discussed in this memo.
8. Authors' Addresses
Keith McCloghrie
cisco Systems, Inc.
170 West Tasman Drive,
San Jose CA 95134-1706.
Phone: (408) 526-5260
EMail: kzm@cisco.com
Fred Baker
cisco Systems, Inc.
519 Lado Drive
Santa Barbara, CA 93111
Phone: (805) 681-0115
EMail: fred@cisco.com
Eric B. Decker
cisco Systems, Inc.
1525 O'Brien Dr.
Menlo Park, California 94025
Phone: (415) 688-8241
EMail: cire@cisco.com
AI ELI5
On this page
PROBLEMToken Ring end stations that use IEEE source routing keep a database of routes to other stations, but there was no standard way for network management to look at it.
MECHANISMThe memo defines one SNMPv2 MIB table, the 802.5 Station Source Routing Table, with a route control value, the list of bridge and ring IDs, and a row status for each destination MAC address.
STATUS TODAYIt is an incremental update to RFC 1748, written as a separate document only because RFC 1748 was further along in standardization. The RFC is now Historic.
§1What the MIB Is For
RFC 1749 defines a portion of the Management Information Base (MIB) used by network management protocols. It covers the managed objects that IEEE 802.5 end stations use to manage source routes on a Token Ring network where IEEE source routing is in use.
The memo is an incremental update to RFC 1748, the IEEE 802.5 MIB. It is documented separately only because of the maturity of RFC 1748 within the Internet standardization process. Where RFC 1525 defines the source-routing objects for source-routing and SRT bridges, this memo defines them for source-routing end stations.
Some stations on a ring need to know the way to other stations. This memo is a standard list of questions you can ask a station about those ways.
§3.1Source Routing on Token Ring
Source routing extends 802.5 by giving each ring in the extended LAN a unique ring number, and each source routing bridge connection to a ring a bridge number. A Routing Information Field (RIF) must be included in frames that need to cross more than one ring.
The RIF is a 2-octet Routing Control (RC) field followed by 0 to 8 Routing Descriptor (RD) fields of 2 octets each. The RC field carries an explorer indicator, the length of the RIF, a direction bit that says how to read the RDs, and the maximum frame length. Each RD holds a ring number and a bridge number.
Each hallway ring gets a number and each door between rings gets a number. A message carries a list of those numbers so it knows which doors to go through.
| Field | Name | Size | Value | Description |
|---|---|---|---|---|
RC | RC | 2 bytes | Routing Control field, octets 1 and 2. | |
RD-1 | RD | 2 bytes | Routing Descriptor: ring number and bridge number. | |
RD-MORE | RD ... | 2 bytes | Zero to eight RD fields in total, up to octets 17 and 18. |
§4The Station Source Route Table
The memo defines a single table, dot5SrRouteTable, that holds the source routes known by an end station. The module is dot5SrMIB and sits at { mib-2 42 }. Each row is indexed by ifIndex and the destination MAC address, dot5SrRouteDestination.
dot5SrRouteControl: the 2-octet Routing Control field for the route.dot5SrRouteDescr: the embedded sequence of bridge and ring IDs, using theSourceRoutetype, an octet string of 0 to 30 octets.dot5SrRouteStatus: the row status.
An entry is created when a Single Path Explorer or an All Paths Explorer discovers a route to a neighbor not yet in the table, or when an All Paths Explorer finds a better route, such as a shorter one.
The table is a notebook with one line per friend. Each line says which hallways and doors lead to that friend and whether the line is still good.
§3.4Static Routes and Local Destinations
It is unclear how many existing systems let network management create or delete static 802.5 source routes. The memo still supports them through dot5SrRouteStatus, but the compliance statement only requires read access to it, so stations without static routes can still comply. Only the active value needs to be supported, and write access to dot5SrRouteControl and dot5SrRouteDescr is also not required.
Destinations on the same ring as the instrumented interface should also appear in the table. For them, dot5SrRouteDescr is the zero-length string and dot5SrRouteControl has the corresponding value.
Friends in your own hallway need no directions, so their line has an empty route. And a station does not have to let anyone write in its notebook.
§7Security Considerations
The memo's security section says only that security issues are not discussed. It sets no access-control or protection rules of its own, beyond the framework it builds on, the SNMPv2 Network Management Framework of RFC 1442, MIB-II, RFC 1445 and RFC 1448.
The authors did not write anything about keeping the notebooks safe from snoopers in this memo.
§6References
[1]RFC 1442Case, J., McCloghrie, K., Rose, M., and S. Waldbusser, "Structure of Management Information for version 2 of the Simple Network Management Protocol (SNMPv2)", RFC 1442, April 1993.April 1993[2]RFC 1213McCloghrie, K., and M. Rose, Editors, "Management Information Base for Network Management of TCP/IP-based internets: MIB-II", STD 17, RFC 1213, March 1991.March 1991[3]RFC 1445Galvin, J., and K. McCloghrie, "Administrative Model for version 2 of the Simple Network Management Protocol (SNMPv2)", RFC 1445, April 1993.April 1993[4]RFC 1448Case, J., McCloghrie, K., Rose, M., and S. Waldbusser, "Protocol Operations for version 2 of the Simple Network Management Protocol (SNMPv2)", RFC 1448, April 1993.April 1993[6]RFC 1748McCloghrie, K., and E. Decker, "IEEE 802.5 Token Ring MIB using SMIv2", RFC 1748, December 1994.December 1994[7]RFC 1525McCloghrie, K., Decker, E., Langville, P., and A. Rijsinghani, "Definitions of Managed Objects for Source Routing Bridges", RFC 1525, September 1993.September 1993