BAS-TCP-MIB

All MIBs › BAS-TCP-MIB

Organization: Broadband Access Systems

Last Updated: 1998-10-07

Category: DOCSIS and Cable, IP and Core Protocols

Description: Monitors TCP connection statistics and session table on the BAS CMTS management plane.

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What Is BAS-TCP-MIB?

BAS-TCP-MIB is a proprietary MIB for a Broadband Access System (BAS), a class of broadband/CMTS-style aggregation platform, defining TCP-layer objects for the device's IP forwarding and management-plane software stack. It exposes TCP retransmission timeout configuration (basTcpRtoAlgorithm, basTcpRtoMin/Max), connection limits, and counters for active/passive opens, failed attempts, resets, currently established connections, and inbound segments. It is used to monitor the software/network-stack health of the BAS's own TCP implementation rather than physical hardware, helping detect abnormal connection churn, resource exhaustion, or management-plane connectivity problems. It is clearly modeled after the structure of the standard TCP-MIB (RFC 4022/RFC 1213) TCP group, adapted for the BAS platform's IP forwarding component. It is typically deployed on Broadband Access System / CMTS-class aggregation devices in cable or broadband access networks. Engineers can download the BAS-TCP-MIB file directly to load it into their MIB browser.

IPNetwork Monitor allows you to monitor SNMP objects defined in BAS-TCP-MIB. Use the built-in SNMP Monitoring Browser to explore available variables, view their current values and descriptions, and select the objects you want to monitor. You can then create SNMP monitors, configure thresholds, and receive alerts when monitored values change.

Supported Devices

Broadband Access System (BAS) / CMTS-class broadband aggregation device

Monitoring Examples

An administrator would poll basTcpCurrEstab and basTcpAttemptFails from basTcpTable/basTcpEntry to watch for an abnormal spike in failed TCP connection attempts or a sudden drop in current established sessions. A rising basTcpEstabResets count alongside falling basTcpCurrEstab would indicate the BAS's management-plane TCP stack is under stress or experiencing connectivity resets.

What Can Be Monitored

current established TCP connections
TCP connection open/failure counts
TCP reset counts
TCP retransmission timeout configuration
inbound TCP segment counts

Imported Objects

From BAS-MIB

BasChassisId
BasInterfaceId
BasLogicalPortId
BasSlotId
basAliasTcp	OBJECT-IDENTITY

From SNMPv2-SMI

Counter32
Gauge32
Integer32
IpAddress
MODULE-IDENTITY
OBJECT-TYPE

How to Use in IPNetwork Monitor

Example using basTcpActiveOpens OID:

Select a Broadband Access Systems (BAS) CMT (legacy) as the target host to create a monitor — the SNMP service should be up and running on it. Click New Monitor, then check SNMP Custom on the Favorites tab, click Next, and confirm the host. On the next page, click Select... to open the built-in SNMP MIB Browser and type basTcpActiveOpens into the Find box to locate it in the OID tree, selecting the specific row/instance you want to monitor since this is a table column, then select it and click OK. The number of times TCP connections have made a direct transition to the SYN-SENT state from the CLOSED state. On the monitor's Main parameters page you can set the target's SNMP port (default 161), credentials, polling interval, and other settings — see the SNMP Monitor help for details. On the State conditions and Alerting tabs, configure when the monitor should change state and trigger an alert; since this is a Counter32-type OID, Value bounds is the most useful condition here — trigger an alert if the counter increases sharply between polls relative to its normal baseline, since an unexpected spike often reflects a real change in traffic or activity. Click Finish to create the monitor; you can adjust any parameter later.

OIDs

OID symbolic	OID numeric	Type	Access	Description
basAliasTcpMib	1.3.6.1.4.1.3493.2.7.3.1			This module defines the MIB objects for a Broadband Access System IP Forwarding component.
basTcpObjects	1.3.6.1.4.1.3493.2.7.3.1.1
basTcpTable	1.3.6.1.4.1.3493.2.7.3.1.1.1		not-accessible	A list of TCP stats
basTcpEntry	1.3.6.1.4.1.3493.2.7.3.1.1.1.1		not-accessible	Objects for the TCP mib.
INT basTcpRtoAlgorithm	1.3.6.1.4.1.3493.2.7.3.1.1.1.1.1	INTEGER	read-only	The algorithm used to determine the timeout value used for retransmitting unacknowledged octets.
I32 basTcpRtoMin	1.3.6.1.4.1.3493.2.7.3.1.1.1.1.2	Integer32	read-only	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.
I32 basTcpRtoMax	1.3.6.1.4.1.3493.2.7.3.1.1.1.1.3	Integer32	read-only	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.
I32 basTcpMaxConn	1.3.6.1.4.1.3493.2.7.3.1.1.1.1.4	Integer32	read-only	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.
C32 basTcpActiveOpensEx	1.3.6.1.4.1.3493.2.7.3.1.1.1.1.5	Counter32	read-only	The number of times TCP connections have made a direct transition to the SYN-SENT state from the CLOSED state.
C32 basTcpPassiveOpens	1.3.6.1.4.1.3493.2.7.3.1.1.1.1.6	Counter32	read-only	The number of times TCP connections have made a direct transition to the SYN-RCVD state from the LISTEN state.
C32 basTcpAttemptFails	1.3.6.1.4.1.3493.2.7.3.1.1.1.1.7	Counter32	read-only	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.
C32 basTcpEstabResets	1.3.6.1.4.1.3493.2.7.3.1.1.1.1.8	Counter32	read-only	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.
G32 basTcpCurrEstab	1.3.6.1.4.1.3493.2.7.3.1.1.1.1.9	Gauge32	read-only	The number of TCP connections for which the current state is either ESTABLISHED or CLOSE- WAIT.
C32 basTcpInSegs	1.3.6.1.4.1.3493.2.7.3.1.1.1.1.10	Counter32	read-only	The total number of segments received, including those received in error. This count includes segments received on currently established connections.
C32 basTcpOutSegs	1.3.6.1.4.1.3493.2.7.3.1.1.1.1.11	Counter32	read-only	The total number of segments sent, including those on current connections but excluding those containing only retransmitted octets.
C32 basTcpRetransSegs	1.3.6.1.4.1.3493.2.7.3.1.1.1.1.12	Counter32	read-only	The total number of segments retransmitted - that is, the number of TCP segments transmitted containing one or more previously transmitted octets.
BAS basTcpChassis	1.3.6.1.4.1.3493.2.7.3.1.1.1.1.13	BasChassisId	not-accessible	The BAS Chassis ID of the Route Server.
BAS basTcpSlot	1.3.6.1.4.1.3493.2.7.3.1.1.1.1.14	BasSlotId	not-accessible	The BAS Slot ID of the Route Server.
NUM basTcpIf	1.3.6.1.4.1.3493.2.7.3.1.1.1.1.15	BasInterfaceId	not-accessible	The BAS interface ID of the Route Server.
BAS basTcpLPort	1.3.6.1.4.1.3493.2.7.3.1.1.1.1.16	BasLogicalPortId	not-accessible	The BAS logical port ID of the Route Server.
basTcpConnTable	1.3.6.1.4.1.3493.2.7.3.1.1.2		not-accessible	A table containing TCP connection-specific information.
basTcpConnEntry	1.3.6.1.4.1.3493.2.7.3.1.1.2.1		not-accessible	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.
INT basTcpConnState	1.3.6.1.4.1.3493.2.7.3.1.1.2.1.1	INTEGER	read-write	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).
IP basTcpConnLocalAddress	1.3.6.1.4.1.3493.2.7.3.1.1.2.1.2	IpAddress	read-only	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.
INT basTcpConnLocalPort	1.3.6.1.4.1.3493.2.7.3.1.1.2.1.3	INTEGER	read-only	The local port number for this TCP connection.
IP basTcpConnRemAddress	1.3.6.1.4.1.3493.2.7.3.1.1.2.1.4	IpAddress	read-only	The remote IP address for this TCP connection.
INT basTcpConnRemPort	1.3.6.1.4.1.3493.2.7.3.1.1.2.1.5	INTEGER	read-only	The remote port number for this TCP connection.
BAS basTcpConnChassis	1.3.6.1.4.1.3493.2.7.3.1.1.2.1.6	BasChassisId	not-accessible	The BAS Chassis ID of the Route Server.
BAS basTcpConnSlot	1.3.6.1.4.1.3493.2.7.3.1.1.2.1.7	BasSlotId	not-accessible	The BAS Slot ID of the Route Server.
NUM basTcpConnIf	1.3.6.1.4.1.3493.2.7.3.1.1.2.1.8	BasInterfaceId	not-accessible	The BAS interface ID of the Route Server.
BAS basTcpConnLPort	1.3.6.1.4.1.3493.2.7.3.1.1.2.1.9	BasLogicalPortId	not-accessible	The BAS logical port ID of the Route Server.
basTcpStatsTable	1.3.6.1.4.1.3493.2.7.3.1.1.3		not-accessible	A list of Route Server forwarding table distribution mechanism statistics.
basTcpStatsEntry	1.3.6.1.4.1.3493.2.7.3.1.1.3.1		not-accessible	Objects for the TCP mib.
C32 basTcpInErrs	1.3.6.1.4.1.3493.2.7.3.1.1.3.1.1	Counter32	read-only	The total number of segments received in error (e.g., bad TCP checksums).
C32 basTcpOutRsts	1.3.6.1.4.1.3493.2.7.3.1.1.3.1.2	Counter32	read-only	The number of TCP segments sent containing the RST flag.
BAS basTcpStatsChassis	1.3.6.1.4.1.3493.2.7.3.1.1.3.1.3	BasChassisId	not-accessible	The BAS Chassis ID of the Route Server.
BAS basTcpStatsSlot	1.3.6.1.4.1.3493.2.7.3.1.1.3.1.4	BasSlotId	not-accessible	The BAS Slot ID of the Route Server.
NUM basTcpStatsIf	1.3.6.1.4.1.3493.2.7.3.1.1.3.1.5	BasInterfaceId	not-accessible	The BAS interface ID of the Route Server.
BAS basTcpStatsLPort	1.3.6.1.4.1.3493.2.7.3.1.1.3.1.6	BasLogicalPortId	not-accessible	The BAS logical port ID of the Route Server.

RFC description

Broadband Access System TCP statistics MIB for monitoring IP forwarding and TCP connection metrics.

Start monitoring Broadband Access Systems (BAS) CMTS (legacy) with a free 30-day trial of IPNetwork Monitor. Import MIBs, browse SNMP OIDs, create custom SNMP monitors, configure alerts, and monitor any SNMP-enabled network device from a single console.

Download BAS-TCP-MIB