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Unformatted text preview: unter Number of transitions from SYNSENT or SYNRCVD
to CLOSED, plus number of transitions from
SYNRCVD to LISTEN. tcpEstabResets Counter Number of transitions from ESTABLISHED or
CLOSEWAIT states to CLOSED. tcpCurrEstab Gauge Number of connections currently in ESTABLISHED or
CLOSEWAIT states. tcpInSegs Counter Total number of segments received. tcpOutSegs Counter Total number of segments sent, excluding those
containing only retransmitted bytes. tcpRetransSegs Counter Total number of retransmitted segments. tcpInErrs Counter Total number of segments received with an error (such
as invalid checksum). tcpOutRsts Counter Total number of segments sent with RST flag set. Figure 25.27 Simple variables in tcp group.
We can query some of these variables on the system sun:
sun % snmpi -a sun
snmpi> get tcpRtoAlgorithm.0 tcpRtoMin.0 tcpRtoMax.0 tcpMaxConn.0
tcpMaxConn.0=-1 file:///D|/Documents%20and%20Settings/bigini/Doc...omenet2run/tcpip/tcp-ip-illustrated/snmp_sim.htm (24 of 33) [12/09/2001 14.47.40] Chapter 25. SNMP: Simple Network Management Protocol
This system (SunOS 4.1.3) uses the Van Jacobson retransmission timeout algorithm, uses timeouts
between 200 ms and 12.8 seconds, and has no fixed limit on the number of TCP connections. (This
upper limit of 12.8 seconds appears wrong, since most implementations use an upper limit of 64
seconds, as we saw in Chapter 21.)
The tcp group has a single table, the TCP connection table, shown in Figure 25.28. This contains
one row for each connection. Each row contains five variables; the state of the connection, local IP
address, local port number, remote IP address, and remote port number.
index = < tcpConnLocalAddress >.< tcpConnLocalPort >.< tcpConnRemAddress >.<
Name Datatype [1..12] tcpConnState tcpConnLocalAddress IpAddress R/W Description * State of connection: 1 = CLOSED, 2 =
LISTEN, 3 = SYNSENT, 4 = SYNRCVD, 5 =
ESTABLISHED, 6 = FINWAIT1,7=
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This test prep was uploaded on 04/04/2014 for the course ECE EL5373 taught by Professor Guoyang during the Spring '12 term at NYU Poly.
- Spring '12