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3.4.2 Transmission Media MIBs

Other Internet-standard MIBs have been approved for specific transmission media, and are listed under the transmission subtree, {1.3.6.1.2.1.10}. As defined in RFC 1700, these include:

MIB OID RFC

X.25 Packet Layer objects 1.3.6.1.2.1.10.5 1382
CSMA/CD-like objects 1.3.6.1.2.1.10.7 1650
Token Bus-like objects 1.3.6.1.2.1.10.8 1230, 1239
Token Ring-like objects 1.3.6.1.2.1.10.9 1748
FDDI objects 1.3.6.1.2.1.10.15 1285, 1512
X.25 LAPB objects 1.3.6.1.2.1.10.16 1381
DS1 Interface objects 1.3.6.1.2.1.10.18 1406
E1 Interface objects 1.3.6.1.2.1.10.19 1406
PPP objects 1.3.6.1.2.1.10.23 1471
DS3/E3 Interface objects 1.3.6.1.2.1.10.30 1407
SMDS Interface objects 1.3.6.1.2.1.10.31 1694
Frame Relay objects 1.3.6.1.2.1.10.32 1315
RS-232 objects 1.3.6.1.2.1.10.33 1659
Parallel Printer objects 1.3.6.1.2.1.10.34 1660
ARCNET objects 1.3.6.1.2.1.10.35 N/A
ARCNETPLUS objects 1.3.6.1.2.1.10.36 N/A
ATM objects 1.3.6.1.2.1.10.37 1695
Multiprotocol Interconnect over X.25 (miox) 1.3.6.1.2.1.10.38 1461
SONET objects 1.3.6.1.2.1.10.39 1595
Frame relay network service objects 1.3.6.1.2.1.10.44 1695

For more up-to-date information, see the network management section of the “Assigned Numbers” document (currently RFC 1700), or the on-line version of the file (ftp://ftp.isi.edu/in-notes/iana/assignments/network-management-numbers).

3.5. The Ethernet RMON MIB

As networks have become increasingly distributed, geographically and logically, network management has become more challenging. One solution is to place remote management devices, sometimes called probes, on remote segments. The probes act as the eyes and ears of the network management system, providing managers with statistical information. The remote network monitoring (RMON) MIB standardizes the management information sent to and from these probes; it is presented in RFC 1757 [3-15]. A vendor-specific RMON implementation is the focus of “Continuous Monitoring of Remote Networks: The RMON MIB,” in the April 1993 issue of Hewlett-Packard Journal [3-16]. References 3–17 through 3–23 discuss various applications of the RMON architecture.

The RMON MIB is assigned OID {1.3.6.1.2.1.16} and contains 9 groups. All of these groups are optional (not mandatory), but the implementation of some groups requires other groups. For example, the Filter group requires the Packet Capture group. The following is a summary of the nine Ethernet groups shown in Figure 3-19:

Group Description

statistics (1) Provides probe-measured statistics, such as the number and sizes of packets, broadcasts, collisions, and so on.
history (2) Records periodic statistical samples over time that you can use to analyze trends.
alarm (3) Compares statistical samples with preset thresholds, generating alarms when a particular threshold is crossed.
host (4) Maintains statistics of the hosts on the network, including the MAC addresses of the active hosts.
hostTopN (5) Provides reports sorted by host table statistics, indicating which hosts are at the top of the list in a particular category.
matrix (6) Stores statistics in a traffic matrix that tracks conversations between pairs of hosts.
filter (7) Allows packets to be matched according to a filter equation.
capture (8) Allows packets to be captured after they pass through a logical channel.
event (9) Controls the generation and notification of events, which may include SNMP trap messages.


Figure 3-19.  The Ethernet RMON MIB

The current standard, RFC 1757, addresses only Ethernet network monitoring. The next section will discuss the draft for the token ring extensions.

3.6 The Token Ring RMON MIB

The token ring RMON MIB is under development as an extension to the Ethernet RMON MIB discussed in the previous section. Because of the popularity of token ring networks, this MIB has received a great deal of attention [3-24]. Recall that the Ethernet RMON MIB defines nine groups, Statistics through Events. The token ring RMON MIB extends two of these groups, Statistics and History, and adds one unique group. This new group is called tokenRing, with object identifier { rmon 10 }.

The statistics extensions allow an RMON-compatible device to collect token ring MAC-Layer errors and promiscuous errors. The MAC-Layer errors, such as token errors and frame-copied errors, are specific to the token ring protocol; the promiscuous errors, such as counting number of broadcast packages or data packets between 512 and 1023 octets in length, are more general. Similarly, the history information (discussed in Appendix G) is divided into MAC-Layer and promiscuous details. The token ring group contains four sub groups: ring station, which monitors station- and ring-specific events; ring station order, which tracks the network topology; ring station configuration, which controls the removal and/or configuration of stations on the ring; and source routing, which details source routing bridging information. Figure 3-20 illustrates these token ring additions; it also shows the major Ethernet groups for clarification. Reference [3-25] discusses test results of token ring RMON probes and managers.


Figure 3-20.  The token ring RMON MIB


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