Specifications

Specify a Synchronous Serial Interface
Configuring Serial Interfaces IC-71
Specify a Synchronous Serial Interface
To specify a synchronous serial interface and enter interface configuration mode, use one of the
following commands in global configuration mode:
Specify Synchronous Serial Encapsulation
By default, synchronous serial lines use the High-Level Data Link Control (HDLC) serial
encapsulation method, which provides the synchronous framing and error detection functions of
HDLC without windowing or retransmission. The synchronous serial interfaces support the
following serial encapsulation methods:
• Asynchronous Transfer Mode-Data Exchange Interface (ATM-DXI)
• High-Level Data Link Control (HDLC)
• Frame Relay
• Point-to-Point Protocol (PPP)
• Synchronous Data Link Control (SDLC)
• Switched Multimegabit Data Services (SMDS)
• Cisco Serial Tunnel (STUN)
• X.25-based encapsulations
You can define the encapsulation method by using the following command in interface configuration
mode:
Encapsulation methods are set according to the type of protocol or application you configure in the
Cisco IOS software. ATM-DXI is described in this chapter in the section “Configure the CRC.” PPP
is described in the “Configuring Media-Independent PPP and Multilink PPP” chapter in the Dial
Solutions Configuration Guide. The remaining encapsulation methods are defined in their respective
books and chapters describing the protocols or applications. Serial encapsulation methods are also
discussed in the Cisco IOS Interface Command Reference in the chapter “Interface Commands”
under the encapsulation command.
Command Purpose
interface serial number Begin interface configuration.
interface serial slot/port Begin interface configuration for the Cisco 7200 or
Cisco 7500 series routers.
interface serial slot/port-adapter/port Begin interface configuration for the Cisco 7500 series
routers.
interface serial slot/port:channel-group
(Cisco 7000 series)
interface serial number:channel-group
(Cisco 4000 series)
Begin interface configuration for a channelized T1 or
E1 interface.
Command Purpose
encapsulation {atm-dxi | hdlc | frame-relay |
ppp | sdlc-primary | sdlc-secondary | smds |
stun | x25}
Configure synchronous serial encapsulation.