5-5
Ethernet Card Software Feature and Configuration Guide, R7.2
January 2009
Chapter 5 Configuring POS
Framing Mode, Encapsulation, and CRC Support
Configuring POS Interface CRC Size in HDLC Framing
To configure additional properties to match those of the interface at the far end, perform the following
steps, beginning in global configuration mode:
Setting the MTU Size
To set the maximum transmission unit (MTU) size, perform the following steps, beginning in global
configuration mode:
Step 3 Router(config-if)# encapsulation
type
Sets the encapsulation type. Valid values are:
hdlc—Cisco HDLC
lex—(default) LAN extension, special
encapsulation for use with Cisco ONS
Ethernet line cards. When the lex keyword is
used with GFP-F framing it is standard
Mapped Ethernet over GFP-F according to
ITU-T G.7041.
ppp—Point-to-Point Protocol
Step 4 Router(config-if)# no shutdown Restarts the shutdown interface.
Step 5 Router(config)# end Returns to privileged EXEC mode.
Step 6 Router# copy running-config startup-config (Optional) Saves configuration changes to
NVRAM.
Command Purpose
Command Purpose
Step 1 Router(config)# interface pos
number
Activates interface configuration mode to
configure the POS interface.
Step 2 Router(config-if)# crc {16 | 32}Sets the CRC value for HDLC framing. If the
device to which the POS module is connected does
not support the default CRC value of 32, set both
devices to use a value of 16.
Note The CRC value is fixed at a value of 32
under GFP-F framing.
Step 3 Router(config-if)# end Returns to the privileged EXEC mode.
Step 4 Router# copy running-config startup-config (Optional) Saves configuration changes to
NVRAM.
Command Purpose
Step 1 Router(config)# interface pos
number
Activates interface configuration mode to
configure the POS interface.
Step 2 Router(config-if)# mtu
bytes
Configures the MTU size up to a maximum of
9000 bytes. See Tabl e 5-4 for default MTU sizes.