Appendix A. Terminal Server Serial Ports


The following is an excerpt from RFC 1317 and illustrates the way in which serial interfaces are modeled in this MIB. The object instances supported by a real device that implements this MIB can be viewed using a MIB browser and pointing it at an appropriately configured terminal server.

 RFC1317-MIB DEFINITIONS ::= BEGIN     IMPORTS        Counter           FROM RFC1155-SMI        transmission           FROM RFC1213-MIB        OBJECT-TYPE           FROM RFC-1212;   -- this is the MIB module for RS-232-like hardware devices     rs232    OBJECT IDENTIFIER ::= { transmission 33 }     -- the generic RS-232-like group     -- Implementation of this group is mandatory for all     -- systems that have RS-232-like hardware ports     -- supporting higher level services such as character     -- streams or network interfaces   rs232Number OBJECT-TYPE     SYNTAX INTEGER     ACCESS read-only     STATUS mandatory     DESCRIPTION "The number of ports (regardless of their current  state) in the RS-232-like general port table."     ::= { rs232 1 } rs232AsyncPortTable OBJECT-TYPE     SYNTAX SEQUENCE OF Rs232AsyncPortEntry     ACCESS not-accessible     STATUS mandatory     DESCRIPTION "A list of asynchronous port entries.  The maximum entry number is given by the value of rs232Number. Entries need not exist for synchronous ports."     ::= { rs232 3 } rs232AsyncPortEntry OBJECT-TYPE     SYNTAX Rs232AsyncPortEntry     ACCESS not-accessible     STATUS mandatory     DESCRIPTION "Status and parameter values for an asynchronous port."     INDEX { rs232AsyncPortIndex }     ::= { rs232AsyncPortTable 1 } Rs232AsyncPortEntry ::=     SEQUENCE {     rs232AsyncPortIndex INTEGER,     rs232AsyncPortBits INTEGER,     rs232AsyncPortStopBits INTEGER,     rs232AsyncPortParity INTEGER,     rs232AsyncPortAutobaud INTEGER,     rs232AsyncPortParityErrs Counter,     rs232AsyncPortFramingErrs Counter,     rs232AsyncPortOverrunErrs Counter } 

This MIB provides all of the above objects for use when managing serial devices. Each entry in the table corresponds to a serial interface, and the other columns provide access to configuration data such as the number of bits in a data word (rs232AsyncPortBits) , the number of stop bits (rs232AsyncPortStopBits) , and the port parity (rs232AsyncPortParity) . A network management system reads the values of all entries in the rs232AsyncPortTable and sets the values of the port parameters as required. An example would be an appropriately configured 10-port terminal server, which would have 10 entries in this table. By sending a block of SNMP GetRequest messages, the entire table can be retrieved. If required, the user can also send a block of SNMP SetRequest messages in order to modify the rows in rs232AsyncPortTable . The following is the complete definition of the columns of this table:

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rs232AsyncPortIndex OBJECT-TYPE SYNTAX INTEGER ACCESS read-only STATUS mandatory DESCRIPTION "A unique value for each port. Its value is the same as rs232PortIndex for the port." ::= { rs232AsyncPortEntry 1 } rs232AsyncPortBits OBJECT-TYPE SYNTAX INTEGER (5..8) ACCESS read-write STATUS mandatory DESCRIPTION "The port's number of bits in a character." ::= { rs232AsyncPortEntry 2 } rs232AsyncPortStopBits OBJECT-TYPE SYNTAX INTEGER { one(1), two(2), one-and-half(3), dynamic(4) } ACCESS read-write STATUS mandatory DESCRIPTION "The port's number of stop bits." ::= { rs232AsyncPortEntry 3 } rs232AsyncPortParity OBJECT-TYPE SYNTAX INTEGER { none(1), odd(2), even(3), mark(4), space(5) } ACCESS read-write STATUS mandatory DESCRIPTION "The port's sense of a character parity bit." ::= { rs232AsyncPortEntry 4 } rs232AsyncPortAutobaud OBJECT-TYPE SYNTAX INTEGER { enabled(1), disabled(2) } ACCESS read-write STATUS mandatory DESCRIPTION "A control for the port's ability to automatically sense input speed. When graphics/ccc.gif rs232PortAutoBaud is 'enabled', a port may autobaud to values different from the set graphics/ccc.gif values for speed, parity, and character size. As a result a network management system graphics/ccc.gif may temporarily observe values different from what was previously set." ::= { rs232AsyncPortEntry 5 } rs232AsyncPortParityErrs OBJECT-TYPE SYNTAX Counter ACCESS read-only STATUS mandatory DESCRIPTION "Total number of characters with a parity error, input from the port since system graphics/ccc.gif re-initialization and while the port state was 'up' or 'test'." ::= { rs232AsyncPortEntry 6 } rs232AsyncPortFramingErrs OBJECT-TYPE SYNTAX Counter ACCESS read-only STATUS mandatory DESCRIPTION "Total number of characters with a framing error, input from the port since system graphics/ccc.gif re-initialization and while the port state was 'up' or 'test'." ::= { rs232AsyncPortEntry 7 } rs232AsyncPortOverrunErrs OBJECT-TYPE SYNTAX Counter ACCESS read-only STATUS mandatory DESCRIPTION "Total number of characters with an overrun error, input from the port since system graphics/ccc.gif re-initialization and while the port state was 'up' or 'test'." ::= { rs232AsyncPortEntry 8 }


Network Management, MIBs and MPLS
Network Management, MIBs and MPLS: Principles, Design and Implementation
ISBN: 0131011138
EAN: 2147483647
Year: 2003
Pages: 150

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