Cisco IOS in a Nutshell, 2nd Edition

Name

encapsulation (interface) — interface

Synopsis

encapsulation type
encapsulation dot1q vlan-id [native]
encapsulation isl vlan-id
no encapsulation

Configures

Encapsulation method used by the interface

Default

Depends on interface

Description

This command sets the encapsulation method for this interface. Possible values for the encapsulation type are atm-dxi, bstun (block serial tunnel), dot1q, frame-relay (see Chapter 6), hdlc, isl, lapb, ppp, sde, dlc, and smds.

For Frame Relay interfaces, the options are cisco and ietf. The default is cisco, which is Cisco’s proprietary encapsulation method. ietf sets the encapsulation method to the IETF standard, which is used when connecting to another vendor’s Frame Relay router or switch.

For interfaces that are compatible, such as Fast Ethernet interfaces, you can enable dot1q to apply a VLAN ID to the interface. native is an optional keyword that sets the VLAN ID value of the port to the value specified by vlan-id. To enable ISL encapsulation on an interface, use the isl keyword followed by the VLAN ID you wish to use. For more information on dot1q and ISL encapsulation, see Chapter 14.

Example

The following code uses hdlc encapsulation on a serial line:

interface serial0
  encapsulation hdlc

This code uses PPP on an ISDN line:

interface bri0
  encapsulation ppp

This code sets vlan 101 to a subinterface:

interface fastethernet0/1.101
  encapsulation dot1q 101