Cisco Systems PA-E3, PA-2E3 manual Conﬁguring Cyclic Redundancy Checks, Specifying E3 Framing

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Configuring Cyclic Redundancy Checks

Specifying E3 Framing

In interface conﬁguration mode, specify E3 framing by entering the framing {g751 bypass} conﬁguration subcommand, as in the following example:

router(config-if)# framing g751

Use the no form of this command to return to the default, which is G.751 framing.

Note If you use the bypass option, scrambling must be set to the default, disabled; the DSU mode must be set to the default, 0; and the DSU bandwidth must be set to the default, 34010.

Setting the Cable Length

In interface conﬁguration mode, set the cable length (0 to 450 feet), as in the following example:

router(config-if)# cablelength 250

Use the no form of this command to return to the default, which is 10 feet.

Conﬁguring Cyclic Redundancy Checks

The PA-E3 uses a 16-bit cyclic redundancy check (CRC) by default; it also supports a 32-bit CRC.

The CRC is an error-checking technique that uses a calculated numeric value to detect errors in transmitted data. The sender of a data frame divides the bits in the frame message by a predetermined number to calculate a remainder or frame check sequence (FCS). Before sending the frame, the sender appends the FCS value to the message so that the frame contents are exactly divisible by the predetermined number. The receiver divides the frame contents by the same predetermined number that the sender used to calculate the FCS. If the result is not 0, the receiver assumes that a transmission error occurred and sends a request to the sender to resend the frame.

Note To enable a 32-bit CRC on an interface, follow Step 1 and Step 2 of the preceding procedure (enter conﬁguration mode and specify the slot and port address of the PA-E3, and the interface port number for a VIP2), and then enter the command crc 32. Enter Ctrl-Zto exit from conﬁguration mode.

For a Cisco 7100 series, Cisco 7200 series, or Cisco uBR7200 series router, use the following example:

router# configure terminal

Enter configuration commands, one per line. End with CNTL/Z. router(config)#

router(config)# interface serial 3/0

router(config-int)# crc 32

Ctrl-z

8-10PA-E3 Serial Port Adapter Installation and Configuration

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Contents PA-E3 Serial Port Adapter Installation and Configuration Corporate HeadquartersPage Preface ObjectivesOrganization Section Title DescriptionRelated Documentation Related Documentation Section Title DescriptionRelated Documentation Cisco Connection Online Cisco Connection OnlineDocumentation CD-ROM Overview Port Adapter OverviewPort Adapter Overview One-Port PA-E3 Serial Port AdapterPA-E3 Serial Port Adapter Features PA-E3 Serial Port Adapter FeaturesManagement Information Base PA-E3 Port Adapter LEDsPA-E3 Receptacles and Cables PA-E3 Receptacles and CablesPA-E3 Port Adapter LEDs Name Color State DescriptionInteroperability Guidelines for PA-E3 DSUs 6PA-E3 Serial Port Adapter Installation and Configuration Preparing for Installation Parts and Tools RequiredPA-2E3 Software and Hardware RequirementsSoftware and Hardware Requirements Safety Guidelines Safety Guidelines4PA-E3 Serial Port Adapter Installation and Configuration Telephone Wiring Guidelines Electrical Equipment GuidelinesPreventing Electrostatic Discharge Damage Electrical Equipment GuidelinesCompliance Information Babt ComplianceITI-T Compliance TBR24 ComplianceVIP2 and the PA-E3 OverviewOverview Dimm U5PA-E3 in port adapter Slot PA-E3 in port adapter slot Removing a Port Adapter Removing a Port AdapterInstalling a Port Adapter Installing a Port AdapterAligning a Port Adapter in a Port Adapter Slot H3152 8PA-E3 Serial Port Adapter Installation and Configuration Catalyst RSM/VIP2 and the PA-E3 Port adapter securing screw Removing a Port Adapter Installing a Port Adapter Aligning a Port Adapter in a Port Adapter Slot 6PA-E3 Serial Port Adapter Installation and Configuration Cisco 7200 Series and the PA-E3 Cisco 7206 with a PA-E3 in Port Adapter SlotPort adapter Handle Lever unlocked Position Handling a Port Adapter Port adapter Handle Cisco uBR7200 Series and the PA-E3 Port adapters Port adapters Port adapter lever in unlocked position Inside slot guide PC board Metal carrier Port adapter retention clip in locked position 6PA-E3 Serial Port Adapter Installation and Configuration Installation Overview Cisco 7100 Series and the PA-E3Cisco 7140 Series Router-Port Adapter Slot 4 Location Installing a Port Adapter Guides Configuring the PA-E3 Interfaces Using the Exec Command InterpreterCisco 7200 Series and Cisco uBR7200 Series Ports Cisco 7200 Series and Cisco uBR7200 Series Ports Cisco 7206 Serial Port Number ExampleVIP2 Ports PA-E3 Interface Port Address Example- Cisco uBR7246 ShownCatalyst RSM/VIP2 Ports Catalyst RSM/VIP2 PortsWith port adapters Route Switch ModuleCisco 7100 Series Ports Performing a Basic Configuration Performing a Basic ConﬁgurationCustomizing the PA-E3 Configuration ExampleConﬁguration Example Setting the Bandwidth Deﬁning the DSU ModeSetting the Bandwidth Deﬁning Set Bit NationalSetting the Cable Length Configuring Cyclic Redundancy ChecksConﬁguring Cyclic Redundancy Checks Specifying E3 FramingChecking the Conﬁguration Using show Commands to Verify StatusChecking the Configuration Checking the Configuration Step NumberRouter# show interfaces serial 2/0 14PA-E3 Serial Port Adapter Installation and Configuration Router# show controllers serial 0/1 Serial0/1 16PA-E3 Serial Port Adapter Installation and Configuration 73-1684-03 18PA-E3 Serial Port Adapter Installation and Configuration Using the ping Command to Verify Network Connection Using the ping Command to Verify Network ConnectionUsing the loopback Command to Verify the Physical Interface Using the loopback Command to Verify the Physical Interface 22PA-E3 Serial Port Adapter Installation and Configuration