Serial port clock rate

Valid values are 16 and The default is CRC is an error-checking technique that uses a calculated numeric value to detect errors in transmitted data. The designators 16 and 32 indicate the length in bits of the frame check sequence FCS. A CRC of 32 bits provides more powerful error detection, but adds overhead. Both the sender and receiver must use the same setting. To disable this function, use the no form of this command.

This command is available for the JT2 6. This command is useful for checking data integrity while operating in framed mode. CRC5 provides additional protection for a frame alignment signal under noisy conditions.

For data transmission at JT2 6. This command was implemented on the Cisco series router and the E1-G. This command applies to the Cisco series, Cisco series, and Cisco series routers.

CRC4 provides additional protection for a frame alignment signal under noisy conditions. For data transmission at E1 2. To define a severely errored second SES by specifying the number of cyclic redundancy check CRC errors that occur in one second, use the crc-threshold command in controller configuration mode.

To return to the default value, use the no form of this command. Default is To return the ctunnel to the default cisco mode, use the no form of this command. Optional Returns the ctunnel mode to the default cisco.

The implementation of this feature does not include support for GRE header fields such as those used to specify checksums, keys, or sequencing. Any packets received which specify the use of these features will be dropped.

The default ctunnel mode continues to use the standard Cisco encapsulation. Both ends of the tunnel must be configured with the same mode for it to work. If you want to tunnel ipv6 packets you must use the new gre mode. The following example configures a CTunnel from one router to another and shows the CTunnel destination set to The ctunnel mode is set to gre to transport IPv6 packets.

Sets a primary or secondary IP address for an interface. To return each interface to store-and-forward switching, use the no form of this command. Optional Selects cut-through switching technology on received data. Optional Selects cut-through switching technology on transmitted data. Store-and-forward switching technology that is, no cut-through.

Cut-through mode allows switched packets to be transmitted after 64 bytes are received. The transmission of the packets can start before the end of the packet arrives. This reduces the time spent in the switch, but allows packets to be transmitted with bad cyclical redundancy checks CRCs , because the transmission is initiated before the CRC is received or checked.

Store-and-forward mode waits for the entire packet to be received before that packet is forwarded, but will check the CRC before starting transmission. Skip to content Skip to search Skip to footer. Book Contents Book Contents. Find Matches in This Book.

PDF - Complete Book Updated: July 6, Chapter: clock rate through cut-through. Command Default No clock rate is configured. Router show running-config Building configuration Note If you configure a clock rate that exceeds the maximum limit, the configuration will fail. Note This keyword is not supported on CEM serial interfaces. Usage Guidelines Using the no form of this command on a DCE interface sets the clock rate to the hardware-dependent default value. Examples The following example shows how to determine the exact clock rate that the serial interface was rounded to by using the show running-config command.

Examples This example shows the statistics for the current CEM configuration. Command Default No clock rate is set. Usage Guidelines This command uses a synchronized clock on the serial port. Examples The following example shows how to configure the clock rate on serial port 1 in DCE mode: Router config interface serial 1 Router config-if clock rate network-clock Related Commands Command Description clock rate line Configures the line clock rate for serial ports 0 or 1 in DTE mode.

Command Default The default value is line. Command History Release Modification Command Default The default is internal. Usage Guidelines When the clock source is internal, the port receive Rx clock is not eligible as the system clock source. Usage Guidelines To use the clocking coming in from a T1 line, configure the clock source line primary command on the T1 interface that has the most reliable clocking. Examples The following example configures the Cisco AS access server to use T1 controller 0 as the primary clock source and T1 controller 1 as the secondary clock source: Router config controller t1 0 Router config-controller clock source line primary Router config controller t1 1 Router config-controller clock source line secondary clock source CEM To configure the clock source of a circuit emulation CEM network module port, use the clock source command in CEM configuration mode or controller configuration mode.

XE Everest Three new keywords are used to specify the preferred mode: closed-loop --Specifies the closed loop mode. Note Do not use the closed loop mode in applications where the clocks are different for the two directions of the T1 or E1 link.

Cisco and Cisco Series Routers The default clock source is line. Cisco Series Router The default clock source is internal. Clocking on a T1 Line To use the clocking coming in from a T1 line, configure the clock source line primary command on the controller that has the most reliable clocking. Cisco Series Router The clock source cannot be specified as line on both ends of the connection.

Command Default The internal clock source is used. Usage Guidelines If you do not specify the clock source command, the default internal clock source is used by the CT3IP. Note This command replaces the pos internal-clock command. Command Default Cisco , Cisco , and Cisco Series The clock source is obtained from the receive data stream of the line. The loop keyword was added. Cisco AS Access Servers To use the clocking coming in from a T1 line, configure the clock source line primary command on the controller that has the most reliable clocking.

Examples Examples The following example shows how to configure the G. Command Default Clock source is line for the J1 controller. Usage Guidelines If multiple network modules are present in the router, then each J1 controller must be given a separate priority by configuration of the network-clock-select command.

Command Default The default is line. Command Default The internal clock source is used for T3 controllers. Usage Guidelines If you do not specify the clock source command, the default clock source is used. Note For a back-to-back connection between two T3 or E3 network modules, one controller must be configured for internal clocking while the other controller must be configured for line clocking.

Command Default The default state is on. Usage Guidelines You can use the clock switchover command to switch the clock source over to internal clock. Command Default This command is disabled by default.

Cisco IOS Release 3. Usage Guidelines This command defines a new clock port and enters clock port configuration mode. Usage Guidelines In normal operation, the FDDI interface is operational once the interface is connected and configured.

Usage Guidelines In normal operation, the FDDI interface is operational once the interface is connected and configured, and is turned on using the no shutdown command in interface configuration mode. On Cisco series and on VIP2s in Cisco series, specifying the compress stac command with no options causes the router to use the fastest available compression method for PPP encapsulation only: If the router contains a compression service adapter CSA , compression is performed in the CSA hardware hardware compression.

Command Default Compression is disabled. Note This command replaces the compress predictor command. Usage Guidelines Point-to-Point Compression Compression reduces the size of frames through lossless data compression.

Public Data Network Connections Compression requires that both ends of the serial link be configured to use compression. Cisco and Cisco Series Using CSA hardware compression on Cisco series routers and Cisco series routers removes the compression and decompression responsibilities from the VIP2 or the main processor installed in the router. Table 2. Predictor Bottleneck is the result of line bandwidth or hardware compression on the CSA is available.

Stacker Most files are already compressed. Table 3. Note The best performance data compression algorithms adjust their compression methodology as they identify patterns in the data. This example does not set the MTU size and the maximum bits per frame N1 ; we recommend that you do not change those LAPB parameters for Stacker compression: Router config interface serial 0 Router config-if encapsulation lapb Router config-if compress predictor The following example configures BRI interface 0 to perform MPPC: Router config interface BRI0 Router config-if ip unnumbered ethernet0 Router config-if encapsulation ppp Router config-if isdn spid1 Router config-if dialer map ip Examples The following example specifies that hardware compression should be activated for CAIM interface 0: Router config-if encapsulation ppp Router config-if compress stac caim 0 Related Commands Command Description clear aim Clears data compression AIM registers and resets the hardware.

Table 4. This command effectively deactivates the connection. Note If the auto option is used, BeiDou will not be part of the selected constellations. Command Default No default behavior or values. Examples The following example shows how to configure the constellations: Router configure terminal Router config gnss slot r0 Router config-gnss constellation auto Related Commands Command Description gnss Configures the GNSS on the router. Command Default The input control lead sampling rate defaults to 0 no sampling.

Usage Guidelines This command applies only to serial channels. Examples The following example shows how to configure the ingress control-lead sampling rate to 20 samples per second on a serial CEM port. Router config-cem control-lead sampling-rate 20 Related Commands Command Description cem Enters circuit emulation configuration mode.

Table 5. Usage Guidelines The state of each output control lead may be specified to assume a constant level on or off or to change on the basis of the state of any input control lead, either at the local data port or at the remote data port.

Examples The following example shows how to specify the state of an output control lead. Router config-cem control-lead state active cts on Related Commands Command Description cem Enters circuit emulation configuration mode.

Usage Guidelines T1 or E1 Fractional Data Lines This command is used in configurations where the router or access server is intended to communicate with a T1 or E1 fractional data line. Usage Guidelines This command is used to enter controller configuration mode for the controller in the specified slot and port. Command Default No E3 controller is configured.

Usage Guidelines This command is used to configure the Mediatype controller mode. Usage Guidelines The parameters used for protection group controller are executed after using this command. Examples The following example shows how to configure protection group: enable configure terminal protection-group type STS48c controller protection group type STS48c cem-group cep end Related Commands Command Description show protection-group Verifies the protection group configuration.

The range is Command Default The default port is 0. Command Default No T1 or E1controller is configured. Usage Guidelines This command is used in configurations where the router or access server is intended to communicate with a T1 or E1 fractional data line.

Cisco Series No T3 controller is configured. No default behavior or values. Usage Guidelines If you attempt to download a version of the software older than what is currently running on the LAN Extender, a warning message is displayed. Examples The following example copies the executable image namexx to LAN Extender interface 0: Router copy flash lex 0 Name of file to copy? This command does not have a not form.

Command Default CRC5 checking is disabled. Usage Guidelines This command is available for the JT2 6. Usage Guidelines This command applies to the Cisco series, Cisco series, and Cisco series routers. This command does not apply to an E1 port. Command Default Cisco encapsulation tunnel mode is the default.

Examples The following example configures a CTunnel from one router to another and shows the CTunnel destination set to Usage Guidelines Cut-through mode allows switched packets to be transmitted after 64 bytes are received. Was this Document Helpful? Yes No Feedback. This command was introduced. Clock rate value, which can be changed as follows: aal2 -- For Cisco series routers, the minimum value for asymmetric digital subscriber line ADSL and symmetrical high-data-rate digital subscriber line G.

Displays the current configuration. Desired clock rate, in bits per second bps : , , , , , , , , , , , , , , , , , , or For some synchronous serial port adapters a nonstandard clock rate can be used. Displays circuit emulation statistics.

Recovers the clock from the line. Uses local loop timing. Selects a source for the network clock. Clock source on the active line. Primary TDM clock source. Secondary TDM clock source. Displays CEM channel statistics. Selects the frame type for the T1 or E1 data line.

Selects the line code type for T1 or E1 line. Specifies a name for the clock port. Creates a PTP clock instance.

Optional Selects Physical Sublayer A. Optional Selects Physical Sublayer B. Stops the CMT processes. Starts the CMT processes. Optional Specifies the CSA to use for a particular interface. The following keywords were added: distributed software csa slot. The following keywords were added: mppc ignore-pfc. Bottleneck is caused by the load on the router.

Most files are already compressed. Stacker kbps. Predictor kbps. Specifies operation of a serial interface as an X. Allows an EXEC process on a line. Displays compression statistics.

Unique name for this connection. Specified vlan on two GE interfaces on the router. Shuts down the connection. Displays the status of interworking connections.

Enables detection and locking to the Galileo constellation. Enables detection and locking to the GPS constellation. Enables detection and locking to the QZSS constellation.

IOS-XE 3. Configures the GNSS on the router. Configures the pulse per second from the GNSS module. Resets the device to its default state. Exists the GNSS sub mode. Clears CEM channel statistics. Active template configuration. Failed template configuration.

Activates the lead. Deactivates the lead. Specifies the control lead state to follow. Optional Specifies a local lead state. Optional Specifies a remote lead state. Configures the sampling rate of input control leads.

T1 controller. E1 controller. J1 controller. Resets the T1 or E1 controller. Displays information about the J1 link. Configures the controller status. Number of the chassis slot that contains the interface, where: slot--Chassis slot number. Displays platform DWDM alarm history.

Configures a transport mode. Displays information about E3 controllers. Displays information about T3 controllers. Physical slot number of the interface.

Bay of the interface. Mediatype port number. Support for this command was introduced on the NCS Series. Identifier of the interface. Verifies the protection group configuration. Physical sub-slot or bay number. The STM number ranges from 1 to 4. Verifies controller SDH configuration. Configures the path operation mode. Specifies T1 controller. Specifies E1 controller. Specifies the slot number of the interface. Specifies the bay number of the interface.

If no bandwidth command has been configured on the interface, Routing protocols and QOS will assume the line is running at the maximum speed supported by the interface which can result in incorrect routing and incorrect prioritization of packets. When you set the clock rate for a serial interface, you are setting the speed of the interface, in other words, the bandwidth bandwidth meaning rate of data transfer.

As mentioned in the above post, there is also an interface sub-command available; bandwidth. The above formula is to calculate cost for any given outgoing interface to reach any particular subnet in a route. The OSPF formula can be a little confusing. Go back to Tutorial. Bandwidth and Clock Rate on Serial Interfaces. Serial also uses these settings as a lower-level device filter driver for a device that requires a UART-compatible interface.

Serial queries these registry entry values when it adds the device. If a device-specific entry value is not present, Serial uses a Serial service value. However, the device can be set to any non-NULL string. If the device is configured as a COM port , Serial uses the port name to create a symbolic link name for the device. The default value of PortName is an empty string.

The use of Identifier is obsolete and should not be used with Microsoft Windows and later drivers. For a description, see the PortName entry value.

If MultiportDevice is 0x, the serial port is a stand-alone device; otherwise, the serial port is on a multiport device. The default value of MultiportDevice is 0x The Indexed entry value specifies whether a port is bitmapped or indexed. The default value of PortIndex is 0x The default value of ClockRate is 1,, Hertz. If Indexed is nonzero, the port is indexed; otherwise, the port is bitmapped.

Indexed is used in conjunction with the PortIndex entry value. The default value of Indexed is 0x