Product manual

cvcccccCisco
Cisco™ CCNA : Frame Relay
Copyright © 2011 SimulationExams.com * All trademarks are duly recognised
* Best printed in landscape mode
CCNA Network Simulator CCNA Exam Simulator CCENT Exam Simulator CCNA ICND2 Exam Simulator CCNP BSCI Exam Simulator
Types of virtual circuits (Vcs) in Frame Relay
Frame Relay is purely a Layer 2 standard.
Two types of Vcs in FR
1. Permanent Virtual Circuits (PVCs): these are permanently established connections that are used
for frequent and consistent data transfers between DTEs across a Frame Relay cloud.
2. Switched Virtual Circuits (SVCs): these are temporary connections used in situations requiring
only occasional data transfers between DTEs across Frame Relay cloud. The terms "Call Setup",
"Data Transfer", "Idle", and "Call Termination" are associated with SVCs.
Frame Relay connection types
1. Point-to-Point: In point-to-point connection type, a single sub interface establishes a PVC
connection to another physical interface or sub-interface
2. Multi-point :In multipoint connection type, a single sub-interface is used to establish multiple PVC
connections to several physical interfaces or sub-interfaces. In multipoint Frame-Relay network, split
horizon rule is applicable to broadcast traffic.
DLCI (Data Link Connection Identifier)
Salient features
1. DLCIs have only local significance. It means, the end devices over FR network can have different
DLCI numbers
2. DLCI number is provided by the FR service provider. DLCI number is mapped to Layer 3 protocol
address using 'Frame-Relay map' statement.
3. DLCI numbers must be unique on a router.
Frame relay sub-interfaces
When configuring frame-relay using sub interfaces the physical interfaces on
which sub interfaces are configured would not be assigned any IP address.
Even if one is assigned it should be removed prior to configuring frame-relay.
If an IP address is assigned to physical interface, the sub interfaces defined
within the physical interface will not receive any frames.
Split horizon is a method of preventing a routing loop in a network. To overcome the
split horizon, sub-interfaces can be configured on NBMA networks.
Frame Relay encapsulation types and LMI Types
Cisco supports two types of Frame Relay encapsulation: cisco (default), and ietf.
Use IETF when setting up a frame-relay network between a Cisco router and a non-
Cisco router.
Frame-Relay LMI types are Cisco (default), ANSI, Q933A; LMI type is auto-sensed
in IOS v11.2 and up.
Show frame-relay lmi command shows LMI stats.
DLCI Configuration
The command used to assign dlci number to a sub interface is:
R1(config-if)#frame-relay interface-dlci <dlci-number>
Ex: R1(config-if)#frame-relay interface-dlci 100
Note that prior to issuing the above command; issue the following command to get
into proper sub interface configuration mode:
R1(config)#interface serial number.subinterface-number {multipoint | point-
to-point} Ex: R1(config)#interface serial 0.1 point-to-point