Frame Relay Point to Point Configuration & Connectivity

Wide Area Network

The network that is design for long distance communication is called Wide Area Network. A WAN network uses WAN protocols, WAN interface card to communicate with remote network.

Factors to be considered while selecting a WAN technology

(1) No. of locations

(2) Hours of connectivity

(3) Speed

(4) Cost (Bandwidth + Distance)

(5) Reliability
WAN Encapsulation

WAN encapsulation is used to convert a packet into frame and transfer data to WAN links, Different type of encapsulation are designed for different WAN technologies. The general format of WAN encapsulation is: 

Flage

Address

Control

Data

FCS

Flag

l----------------------------------------------------------l---------------------------l-------------l

                          FH                                             Packet                                   FT

Common WAN Encapsulation
Point-to-Point           High level data link control                                          HDLC

Point-to-Point           Point-to-Point Protocol                                                  PPP

Circuit Switch           Point-to-Point Protocol                                                   PPP

Frame Relay               Frame Relay Cisco                             

Frame Relay               Frame Relay IETF

X.25                               Link Access Procedure Based                                        LAPB

ISDN                             Link Access Procedure Based for D channel            LAPD

ATM                              ATM Adaptation layer 5                                                   AAL5

Point-to-Point WAN technologies

These WAN technologies are used to connect two locations with each other. It is the 24-hour high speed and reliable connectivity. We can setup this WAN technology in three steps: -

Step 1: - Connect the devices according to topology.

Step 2: - Configure Modems.

Step 3: - Configure Router.

Step 1

Point-to-Point WAN Topology

(a) Campus n/w or Drop wire n/w

(c) Managed Leased Line n/w (MLLN)

Line
4 Wire                                     2 Wire
1 -------                                   1
2 ------- Loop 1                    2

3                                                3

4 ------- Loop2                    4 ------- Signal

5 ------  -                                5 -------

6                                               6

7                                               7

8                                               8

Step 2 Configurations of Modems :-- We have to configure various parameters in the modem. There are three different methods to configure these parameters according to Modem.

Method

1) Configuration of modem using Jumper setting/ Dip switches.

2) Configuration of modem using LCD menu.

3) Configuration of Modem using Console/ Terminal.

Step 3 Configuration of Router :-- To configure Router for a Leased line scenario or Point-to-Point n/w, we have to set following parameters: -

1) IP addresses

2) IP routing

3) WAN encapsulation

In Point-to-Point WAN n/w any type of routing can be perform on routers

WAN Encapsulation

Two routers interfaces in Point-to-Point WAN must required to have same WAN encapsulation. Two types of WAN encapsulation are supported in this type of network.

(1) HDLC

(2) PPP

By default, Cisco routers will use Cisco HDLC encapsulation. We can change encapsulation by following command: -

Router#conf ter

Router(config)#interface <type> <no>

Router(config-if)#encapsulation ppp|hdlc

HDLC :-- High Level Data Link Control

HDLC is the modified form of SDLC (Synchronous Data Link Control). SDLC was developed by IBM for router to main frame communication. HDLC is modified for router-to-router communication. Most of manufacturer has developed their proprietary HDLC protocol. So HDLC from one manufacturer is not compatible for other.HDLC encapsulation is designed for Point-to-Point router communication. In HDLC no addressing is required, but still all station address is used in encapsulation. HDLC provides only basic features and error checking for the frame.

PPP – Point-to-Point Protocol          

PPP is an open standard WAN protocol that can be used in Point-to-Point and circuit switching networks. PPP provides various advantages as compared to HDLC. PPP has following special features: -

(1) Authentication

(2) Multi Link

(3) Compression

(4) Call Back

This protocol negotiates the basic feature of PPP. It exchanges the parameter and option to be used with link. LCP supported features are: -

 (1)Authentication, Compression, Multi link & Call back          
 (2)Authentication Phase - optional

      In this phase authentication is performed with peers with the help of one of the following protocol.

(i) Password Authentication Protocol

(ii) Challenge Handshake Authentication Protocol

(iii) Microsoft CHAP

(iv) Shiva PAP (clear text)

(3) Network Control Protocol Phase (NCP) :-- In this phase parameters for routed protocol are established. In NCP, there is one module for each routered protocol.

IPCP     for TCP/IP

IPXCP  for IPX/SPX (internetwork packet exchange/sequenced packet exchange)

CDPCP for CDP etc.

Router 1                                                                     

Router#config ter                                                       

Router(config)#int serial 0                             

Router(config-if)# encapsulation ppp            

Router(config-if)# ppp authentication chap  

Router(config-if)#ip address 10.0.0.1 255.0.0.0

Router(config-if)#no sh

Router(config-if)#exit

Router(config)#hostname chd

chd(config)#username ldh password net123

chd(config)#exit

Router 2

Router#config ter

Router(config)#int serial 1

Router(config-if)#encapsulation ppp

Router(config-if)#ppp authentication chap

Router(config-if)#ip address 10.0.0.2 255.0.0.0

Router(config-if)#no sh

Router(config-if)#exit

Router(config)#hostname ldh

ldh(config)#username chd password net123

ldh(config)#exit

Configuring Compression in PPP :-- In PPP, one of the following three protocols can be used for compression

1. Stac
2. Predictor
3. Microsoft Point-to-Point Compression 

Router#config ter

Router(config)#interface <type> <no>

Router(config-if)#encapsulation ppp

Router(config-if)#compress <Stac|MPPC|Predictor>

Router(config-if)#exit

To display Compression

Router#show compress

PPP debug commands

Router#debug ppp error

Router#debug ppp authentication

Router#debug ppp negotiation

To display PPP status

Router#show interface

LCP Open

LCP Closed

LCP Request sent

LCP Listen

IPCP Open

IPCP Closed

CDPCP Open

CDPCP Closed

Packet Switching

Packet Switching is the wan technology in which all devices are connected to the packet switching exchange. The devices will request packet switching exchange to create a virtual connection then data is transferred over the virtual connection. It is possible to create more than one virtual connection. Simuntasouly and transfer data over them one by one.

Example of Packet Switching Technology are: -

1. X.25
2. Frame Relay

Frame Relay :-- Frame Relay is the Packet switching technology in which virtual connections are established. The frame relay supports only permanent virtual connections. Frame used special addresses called DLCI to create common and virtual connections.

Frame Relay Encapsulation :-- Frame Relay use special type of Encapsulation, Which is specifically designed for this technology. There are two encapsulations are available: -

1.  Frame Relay Cisco
2. Frame Relay IETF (Internet Engineering Task Force)

Frame Relay DLCI 

DLCI stands for Data Link Control Identifier. It is used for addressing purpose. In frame Relay Encapsulation, Virtual Circuits are established and data is transferred on the basis of DLCI. DLCI addresses are different from general addressing scheme. One DLCI address provided for each virtual circuit that we want to create.

 DLCI range 16 - 1017

Virtual Circuit

In packet switching technology there are two types of virtual circuits: -

1. Switched Virtual Circuit (SVC)
2. Permanent Virtual Circuit (PVC)

 Only PVC is supported in Frame Relay technology.

Frame Relay Local Management Interface

LMI are the keepalive signals, which are used to keep the virtual circuit up and running. LMI are exchange between frame relay switch and router. We have to set same LMI on router as specified by the service provider. There are three types of LMI that we can use

(1) CISCO

(2) Q933a

(3) ANSI

R1

Router#config ter

Router(config)#int eth0

Router(config-if)#ip address 172.16.0.1 255.255.0.0

Router(config-if)#no sh

Router(config-if)#exit

Router(config)#ip route 172.30.0.0 255.255.0.0 192.168.10.2

Router(config)#int serial 0

Router(config-if)#encapsulation frame-relay

Router(config-if)#frame-relay lmi-type cisco

Router(config-if)#ip address 192.168.10.1 255.255.255.0

Router(config-if)#frame-relay interface-dlci 300

Router(config-dlci)#exit

Router(config-if)#frame-relay map ip 192.168.10.2 300

Router(config-if)#no sh

Router(config-if)#exit

R2

Router#config ter

Router(config)#int eth0

Router(config-if)#ip address 172.30.0.1 255.255.0.0

Router(config-if)#no sh

Router(config-if)#exit

Router(config)#ip route 172.16.0.0 255.255.0.0 192.168.10.1

Router(config)#int serial 0

Router(config-if)#encapsulation frame-relay

Router(config-if)#frame-relay lmi-type cisco

Router(config-if)#ip address 192.168.10.2 255.255.255.0

Router(config-if)#frame-relay interface-dlci 400

Router(config-dlci)#exit

Router(config-if)#frame-relay map ip 192.168.10.1 400

Router(config-if)#no sh

Router(config-if)#exit

Frame-relay Switch

Router(config)#hostname FR-SW

FR-SW(config)#frame-relay switching

FR-SW(config)#int serial0

FR-SW(config-if)#encapsulation frame-relay

FR-SW(config-if)#no ip address

FR-SW(config-if)#frame-relay intf-type dce

FR-SW(config-if)#frame-relay route 300 int serial 1 400

FR-SW(config-if)#clocka rate 64000

FR-SW(config-if)#no sh

FR-SW(config-if)#exit

FR-SW(config)#int serial1

FR-SW(config-if)#encapsulation frame-relay

FR-SW(config-if)#no ip address

FR-SW(config-if)#frame-relay intf-type dce

FR-SW(config-if)#frame-relay route 400 int serial 0 300

FR-SW(config-if)#clocka rate 64000

FR-SW(config-if)#no sh

FR-SW(config-if)#exit

On physical interface, we can assign only one DLCI address. But in this case, we have to use two DLCI on single interface so we will create a frame relay sub interface (multipoint), which is able to create multiple virtual circuit.

R1

Router#config ter

Router(config)#int eth 0

Router(config-if)#ip address 10.0.0.1 255.0.0.0

Router(config-if)#no sh

Router(config-if)#exit

Router(config)#ip route 172.30.0.0 255.255.0.0 192.168.10.2

Router(config)#ip route 172.20.0.0 255.255.0.0 192.168.10.5

Router(config)#int serial 0

Router(config-if)#encapsulation frame-relay ietf

Router(config-if)#frame-relay lmi-type ansi

Router(config-if)#no ip address

Router(config-if)#no sh

Router(config-if)#exit

Router(config)#interface serial 0.2 multipoint

Router(config-if)#ip address 192.168.10.1 255.255.255.0

Router(config-if)#frame-relay map ip 192.168.10.2 309

Router(config-if)#frame-relay map ip 192.168.10.5 318

Router(config-if)#no sh

Router(config-if)#exit

R2

Router#config ter

Router(config)#interface Ethernet 0

Router(config-if)#ip address 172.30.0.1 255.255.0.0

Router(config-if)#no sh

Router(config-if)#exit

Router(config)#ip route 10.0.0.0 255.0.0.0 192.168.10.1

Router(config)#interface serial 0

Router(config-if)#ip address 192.168.10.2 255.255.255.0

Router(config-if)#encapsulation frame-relay

Router(config-if)#frame-relay interface-dlci 400

Router(config-dlci)#exit

Router(config-if)#frame-relay lmi-type ansi

Router(config-if)#frame-relay map ip 192.168.10.1 400

Router(config-if)#no sh

Router(config-if)#exit

R3

Router#config ter

Router(config)#interface Ethernet 0

Router(config-if)#ip address 172.20.0.1 255.255.0.0

Router(config-if)#no sh

Router(config-if)#exit

Router(config)#ip route 10.0.0.0 255.0.0.0 192.168.10.1

Router(config)#interface serial 0

Router(config-if)#ip address 192.168.10.5 255.255.255.0

Router(config-if)#encapsulation frame-relay

Router(config-if)#frame-relay interface-dlci 701

Router(config-dlci)#exit

Router(config-if)#frame-relay lmi-type ansi

Router(config-if)#frame-relay map ip 192.168.10.1 701

Router(config-if)#no sh

Router(config-if)#exit

Frame-relay Switch

Router(config)#hostname FR-SW

FR-SW(config)#frame-relay switching

FR-SW(config)#int serial0

FR-SW(config-if)#encapsulation frame-relay

FR-SW(config-if)#no ip address

FR-SW(config-if)#frame-relay intf-type dce

FR-SW(config-if)#frame-relay route 309 int serial 1 400

FR-SW(config-if)#frame-relay route 318 int serial 2 701

FR-SW(config-if)#clocka rate 64000

FR-SW(config-if)#no sh

FR-SW(config-if)#exit

FR-SW(config)#int serial1

FR-SW(config-if)#encapsulation frame-relay

FR-SW(config-if)#no ip address

FR-SW(config-if)#frame-relay intf-type dce

FR-SW(config-if)#frame-relay route 400 int serial 0 309

FR-SW(config-if)#clocka rate 64000

FR-SW(config-if)#no sh

FR-SW(config-if)#exit

FR-SW(config)#int serial2

FR-SW(config-if)#encapsulation frame-relay

FR-SW(config-if)#no ip address

FR-SW(config-if)#frame-relay intf-type dce

FR-SW(config-if)#frame-relay route 701 int serial 0 318

FR-SW(config-if)#clocka rate 64000

FR-SW(config-if)#no sh

FR-SW(config-if)#exit

R1

Router#config ter

Router(config)#int eth0

Router(config-if)#ip address 10.0.0.1 255.0.0.0

Router(config-if)#no sh

Router(config-if)#exit

Router(config)#ip route 11.0.0.0 255.0.0.0 192.168.10.6

Router(config)#ip route 12.0.0.0 255.0.0.0 172.16.0.1

Router(config)#interface serial 0

Router(config-if)#encapsulation frame-relay ietf

Router(config-if)#frame-relay lmi-type cisco

Router(config-if)#no ip address

Router(config-if)#no sh

Router(config-if)#exit

Router(config)#interface serial 0.20 point-to-point

Router(config-if)#ip address 192.168.10.5 255.255.255.0

Router(config-if)#frame-relay interface-dlci 300

Router(config-if)#exit

Router(config-if)#frame-relay map ip 192.168.10.6 300

Router(config-if)#no sh

Router(config-if)#exit

Router(config)#interface serial 0.30 point-to-point

Router(config-if)#ip address 172.16.0.2 255.255.0.0

Router(config-if)#frame-relay interface-dlci 309

Router(config-if)#exit

Router(config-if)#frame-relay map ip 172.16.0.1 309

Router(config-if)#no sh

Router(config-if)#exit

Frame Relay Show Command

Router#sh interface <type> <no>

It will be show additional

(i) Encapsulation

(ii) LMI send/receive

Router#sh frame-relay pvc

It will be show

(i) Active/inactive pvc

(ii) Data send/receive over each pvc

(iii) Frame-relay congestion control information

Router#sh frame-relay map

Display the IP to DLCI mapping and pvc status

Frame relay congestion control :-- Frame relay uses three types of information in frame relay encapsulation for congestion control.

1. Backward explicit congestion notice.
2. Forward explicit congestion notice
3. Discard eligibility

Posted in: CCNA