Configuring The Crc Size For T1 - Cisco ASR 1000 Series Software Configuration Manual

Optional Configurations
Command or Action
Step 3 Router(config-if)# encapsulation
encapsulation-type {hdlc | ppp |
frame-relay}
Step 4
Router(config-if)# crc {16 | 32}

Configuring the CRC Size for T1

CRC is an error-checking technique that uses a calculated numeric value to detect errors in transmitted data.
The 1-Port Channelized OC-3/STM-1 SPA and 1-Port Channelized OC-12/STM-4 SPA uses a 16-bit cyclic
redundancy check (CRC) by default, but also supports a 32-bit CRC. 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 set the length of the cyclic redundancy check (CRC) on a T1 interface, use these commands:
SUMMARY STEPS
1. Router# configure terminal
2. Router(config)# interface serial slot/subslot/port:channel-group
3. Router(config-if)# crc {16 | 32}
DETAILED STEPS
Command or Action
Step 1 Router# configure terminal
Step 2 Router(config)# interface serial
slot/subslot/port:channel-group
Example:
Cisco ASR 1000 Series Aggregation Services Routers SIP and SPA Software Configuration Guide, Cisco IOS
XE Everest 16.5
306
Configuring the 1-Port Channelized OC-3/STM-1 SPA and 1-Port Channelized OC-12/STM-4 SPA
Purpose
Sets the encapsulation method on the interface, where:
• hdlc—Sets the High-Level Data Link Control (HDLC) protocol for serial
interface. This encapsulation method provides the synchronous framing
and error detection functions of HDLC without windowing or
retransmission. This is the default for synchronous serial interfaces.
• ppp—Sets point-to-point protocol (PPP) for serial interface.
• frame-relay—Sets Frame Relay (for serial interface).
Selects the CRC size in bits, where:
• 16—16-bit CRC. This is the default
• 32—32-bit CRC.
Purpose
Enters global configuration mode.
Selects the interface to configure and enters interface configuration mode.
• slot/subslot/port:channel-group —Specifies the location of the
interface.
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