> | Lab 6.5.9.1 Frame Relay config - overview Estimated time: 60 min. Objectives: To become familiar with Frame Relay related WAN terminology To understand the requirements and options for Frame Relay communications To simulate the configuration of a Frame Relay switch and links between two routers Background: This lab focuses on the Frame Relay Packet Switching Protocol for connecting devices on a Wide Area Network (WAN). Frame Relay is an industry-standard, switched data link layer protocol that handles multiple virtual circuits using HDLC encapsulation between connected devices (routers). Frame Relay is more efficient than X.25, the protocol for which it is generally considered a replacement. Frame Relay is a very widely used and important WAN communication technology. With this lab you will use a router to create a Frame Relay switch (the cloud) and connected two other routers through it to simulate a wide area link between two LANs. Point-to-Point vs. Frame Relay Two of the most common types of WAN communication links in use today are 1) Leased Dedicated Point-to-Point permanent circuits and 2) Frame Relay Packet-Switched circuits. The prior labs used PPP (and Cisco HDLC) over a (simulated) leased dedicated point-to-point circuit. This assumes the organization that leased the circuit is paying for the full dedicated bandwidth (such as a T1 at 1.544 Mbps) 24 hours a day, 7 days a week whether they actually use the full bandwidth or not. Packet-switched networks enable end stations to dynamically share the network medium (sometimes referred to as "the cloud") and the available bandwidth and it is possible to only pay for the bandwidth you need. This is referred to a Committed Information Rate (CIR). Potential Bandwidth Sharing Frame Relay uses variable-length packets for more efficient and flexible transfers. These packets then are switched between the various network segments (usually phone company Central Offices or COs) until the destination is reached. Statistical multiplexing techniques control network access in a packet-switched network. The advantage of this technique is that it accommodates more flexibility and more efficient use of bandwidth especially between switches within the cloud. Frame Relay is a way of sharing existing T-1 and T-3 lines owned by service providers and potentially getting better use from them. Most telephone companies now provide Frame Relay service for customers who want connections at 56 Kbps to T-1 speeds. Frame Relay Devices - DTE and DCE Devices attached to a Frame Relay WAN fall into two general categories: Data Terminal Equipment (DTE) and Data Circuit-terminating Equipment (DCE). DTEs are typically located on the premises of and owned by a customer. Examples of DTE devices are terminals, personal computers, routers, and bridges. DCEs are usually carrier-owned (phone company) internetworking devices but can be owned by the customer. The purpose of DCE equipment is to provide clocking and switching services in a network, which are the devices that actually transmit data through the WAN cloud In most cases, these are Frame Relay packet switches themselves. CSU/DSU's are considered DCE. The connection between a DTE device and a DCE device consists of both a physical-layer component and a Data link-layer component. The physical component defines the mechanical, electrical, functional, and procedural specifications for the connection between the devices. One of the most commonly used physical-layer interface specifications is the Recommended Standard (RS)-232 specification. The link-layer component defines the protocol that establishes the connection between the DTE device, such as a router, and the DCE device, such as a Frame Relay switch (usually at the phone company CO). Virtual Circuits Frame Relay provides connection-oriented data link layer communication. This means that a defined communication exists between each pair of devices and that these connections are associated with a connection identifier. This service is implemented by using a Frame Relay virtual circuit, which is a logical connection created between two data terminal equipment (DTE) devices across a Frame Relay packet-switched network (PSN). Virtual circuits provide a bi-directional communications path from one DTE device to another and are identified by a Data-Link Connection Identifier (DLCI). A number of virtual circuits can be multiplexed into a single physical circuit for transmission across the network. This capability often can reduce the equipment and network complexity required to connect multiple DTE devices. A virtual circuit can pass through any number of intermediate DCE devices (switches) located within the Frame Relay PSN (Packet Switched Network) or cloud. Frame Relay virtual circuits fall into two categories: Switched Virtual Circuits (SVCs) and Permanent Virtual Circuits (PVCs). PVCs are the most common. Tools / Preparation: Prior to starting the lab, the teacher or lab assistant should have at least 3 of the 5 routers in the standard router lab available. The middle router will act as the Frame Relay Switch and the other routers will connect through it. The middle router must have DCE clock rate and DCE cable ends on both serial ports (S0 and S1). Before beginning this lab you should read the Networking Academy Second Year Companion Guide, Chapter 12 - Frame Relay. You should also review the Semester 4 On-line chapter on Frame Relay. Note: This is a simulated lab since there will not likely be a real circuit with a Frame Relay cloud available for attachment and testing of the configuration changes made to the routers. The purpose of this lab is to practice the process of configuring the routers to connect to a frame relay WAN link. The following is a list of resources required. 3 Cisco routers with the IOS 11.2 or later Middle router serial ports connected to DCE serial cables Hubs and/or switch attached to the end routers Workstation connected to each router's console port Web Site Resources: Routing basics General information on routers 2500 series routers 1600 series routers Terms and acronyms IP routing protocol IOS command summary Introduction to WAN technologies Notes: Select 3 routers which have WAN serial links between them. The middle router will simulate a Frame Relay switch and the end routers will simulate geographically separate sites connected through the Frame Relay "cloud". This lab worksheet uses routers Lab-A, Lab-B and Lab-C. You will configure the two remote routers (Lab-A and Lab-C) first and then the middle Frame Relay router (Lab B). Step 1 - Configure the physical 3-router setup The two cables connected to the middle router (Lab-B) should both be DCE in order to have this router simulate the Frame Relay switch (The DCE cables are labeled on one end). On router Lab-B, connect one of the DCE cables to Serial 0 and the other to Serial 1. The DCE cable from Lab-B serial 1 will connect to a DTE cable going to router Lab-A serial 0 and the Lab-B serial 1 cable will go to the router Lab-C DTE cable on serial 1. Use the tables below for cabling and interfaces.
> Router Frame Relay switch | From Serial Intfc # & Type (DCE / DTE) | To Remote Router Name | To Serial Intf # & Type (DCE / DTE)
> Lab-B | Serial 0 / DCE | Lab-C | Serial 1 / DTE
> Lab-B | Serial 1 / DCE | Lab-A | Serial 0 / DTE
> Use the show controller command to check the DCE/DTE connections. Lab-A#show controller S 0 What does the show controller command for S0 indicate?
> Router | Interface Ethernet 0 | Interface Serial 0 | Interface Serial 1 | Subnet Mask
> Lab-A ( remote ) | 192.5.5.1 | 201.100.11.1 | Not used | 255.255.255.0
> Lab-B ( switch ) | Not used | DLCI 21 | DLCI 20 | N/A
> Lab-C ( remote ) | 223.8.151.1 | Not used | 201.100.11.2 | 255.255.255.0
> Draw the 3 router set up showing cabling, interfaces, IP addresses and DLCIs. (Hint: use the table above for the diagram)
> Step 2 - Check the WAN Interface on remote router Lab-A Connect your workstation to the console port connection on Router Lab-A and use show interface command to answer the following questions: Lab-A# show interface serial 0 What is the IP address and number of subnet bits for this interface? What is the status of the interface and the Line protocol? What is the encapsulation currently set to? Step 3 - Configure the Serial Interface on Lab-A for a Frame Relay Connection Connect your workstation to the console port connection on Router Lab-A and use the following commands to set up Frame Relay on interface Serial 0. Note that if your are using Cisco IOS version 11.2 or newer the Frame Relay DLCI and LMI type can be detected automatically and will not need to be configured manually. Lab-A - Remote Router Frame Relay Configuration
> Prompt and Command | Purpose
> *** Configure Interface S0 *** |
> Lab-A#config t | Configure from terminal
> Lab-A(config)# interface Serial0 | Select interface S0 to configure
> Lab-A(config-if)# ip address 201.100.11.1 255.255.255.0 | Set the IP address and subnet mask for S0 (use the standard router lab IP)
> Lab-A(config-if)# encapsulation frame-relay | Change the data link encapsulation from HDLC to Frame Relay. Use IETF if connecting to non-Cisco router. Default is Cisco encapsulation.
> Lab-A(config-if)# no shutdown | Bring up interface S0
> exit |
> *** Configure Interface E0 *** |
> Lab-A(config)# interface Ethernet0 | Select interface E0
> Lab-A(config-if)# ip address 192.5.5.1 255.255.255.0 | Set the IP address and subnet mask for E0 (use the standard router lab IP)
> Lab-A(config-if)# no shutdown | Bring up interface E0
> exit |
> *** Configure IGRP Routing Protocol *** |
> Lab-A(config)# router igrp 100 | Enables IGRP routing protocol process
> Lab-A(config-router)# network 201.100.11.0 | Selects network 210.100.11.0 to broadcast and receive IGRP updates
> Lab-A(config-router)# network 192.5.5.0 | Selects network 192.5.5.0 to broadcast and receive IGRP updates
> Control Z and Copy run start |
> Step 4 - Use the show running-config interface command to verify the configuration of S0 Lab-A#sh run What information was displayed about Lab-A interface S0? Step 5 - Check the WAN Interface on remote router Lab-C Connect your workstation to the console port connection on Router Lab-C and use show interface command to answer the following questions: Lab-C# show interface serial 1 What is the IP address and number of subnet bits for this interface? What is the status of the interface and the Line protocol? What is the encapsulation currently set to? Step 6 - Configure the Serial Interface on Lab-C for a Frame Relay Connection Connect your workstation to the console port connection on Router Lab-C and use the following commands to set up Frame Relay on interface Serial 1. Note that if you are using Cisco IOS version 11.2 or newer the Frame Relay DLCI and LMI type can be detected automatically. Lab-C - Remote Router Frame Relay Configuration
> Prompt and Command | Purpose
> *** Configure Interface S1 *** |
> Lab-C#config t | Configure from terminal
> Lab-C(config)# interface Serial1 | Select interface S1 to configure
> Lab-C(config-if)# ip address 201.100.11.2 255.255.255.0 | Set the IP address and subnet mask for S1 (use the standard router lab IP)
> Lab-C(config-if)# encapsulation frame-relay | Change the data link encapsulation from HDLC to Frame Relay. Use IETF if connecting to non-Cisco router. Default is Cisco encapsulation.
> Lab-C(config-if)# no shutdown | Bring up interface S1
> exit |
> *** Configure Interface E0 *** |
> Lab-C(config)# interface Ethernet0 | Select interface E0
> Lab-C(config-if)# ip address 223.8.151.1 255.255.255.0 | Set the IP address and subnet mask for E0 (use the standard router lab IP)
> Lab-C(config-if)# no shutdown | Bring up interface E0
> exit |
> *** Configure IGRP Routing Protocol *** |
> Lab-C(config)# router igrp 100 | Enables IGRP routing protocol process
> Lab-C(config-router)# network 201.100.11.0 | Selects network 201.100.11.0 to broadcast and receive IGRP updates
> Lab-C(config-router)# network 223.8.151.0 | Selects network 223.8.151.0 to broadcast and receive IGRP updates
> Control Z and Copy run start |
> Step 7 - Use the show running-config interface command to verify the configuration of S1 Lab-C#sh run What information was displayed about Lab-C interface S1? Step 8 - Configure Lab-B as a Frame Relay Switch Connect your workstation to the console port on Router Lab-B and use the following commands to enable Frame Relay switching and define interfaces Serial 0 and Serial 1 as DCE. Lab-B - Frame Relay Switch configuration
> Prompt and Command | Purpose
> *** Enable Frame Relay Switching *** |
> Lab-B#config t | Configure from terminal
> Lab-B(config)# frame-relay switching | Starts the frame relay switching process
> *** Configure Interface S0 *** |
> Lab-B(config)# interface Serial0 | Select interface E0
> Lab-B(config-if)# no ip address | Specify no IP address for S0
> Lab-B(config-if)# encapsulation frame-relay | Change the Layer 2 data link encapsulation from HDLC to Frame Relay.
> Lab-B(config-if)# clock rate 56000 | Specify the synchronous clock rate for the DCE side of the interface
> Lab-B(config-if)# frame-relay intf-type dce | Specify the interface as a DCE device
> Lab-B(config-if)# frame-relay route 21 interface serial 1 20 | Define frame route so packets coming in on S0 DLCI 21 should go to S1 DLCI 20
> Lab-B(config-if)# no shutdown | Bring up interface S0
> *** Configure Interface S1 *** |
> Lab-B(config)# interface Serial1 | Select interface S1
> Lab-B(config-if)# no ip address | Specify no IP address for S1
> Lab-B(config-if)# encapsulation frame-relay | Change the Layer 2 data link encapsulation from HDLC to Frame Relay.
> Lab-B(config-if)# clock rate 56000 | Specify the synchronous clock rate for the DCE side of the interface
> Lab-B(config-if)# frame-relay intf-type dce | Specify the interface as a DCE device
> Lab-B(config-if)# frame-relay route 20 interface serial 0 21 | Define frame route so packets coming in on S1 DLCI 20 should go to S0 DLCI 21
> Lab-B(config-if)# no shutdown | Bring up interface S0
> Control Z and Copy run start |
Step 9 - Use the show running-config interface command to verify the configuration of S0 and S1. Note that there are several commands added by the router. Lab-B#sh run What information was displayed about Lab-B interface S0? What information was displayed about Lab-B interface S1? Step 10 - Confirm that the Line Is Up by entering the show interface serial 0 command: Lab-A# show interface serial 0 What is the status of the Serial frame link? How many LMI messages were sent and received? What does this mean? What is the LMI type? Step 11 - Verify the Frame Relay PVC status for router Lab-A (remote router) Lab-A# show frame pvc What is the DLCI number of the connection? (DLCI=) What is the status of the PVC? (PVC Status =) Step 12 - Check the Frame Relay map for router Lab-A (remote router) Lab-A# show frame map What is local interface number, IP address of the switch interface and the DLCI of the connection? What is the status of the PVC? Step 13 - Check the LMI status for router Lab-A (remote router) Lab-A# show frame lmi What is local interface number and is it DCE or DTE? Step 14 - Verify the Frame Relay PVC status for router Lab-B (the switch) Lab-B# show frame pvc What are the DLCI numbers of the connections? What is the status of the PVCs? Step 15 - Verify the Frame Relay routing table for router Lab-B (the switch) Lab-B# show frame route What information is shown? Input intf, Input DLCI, Output Intf, Output DLCI, Status Step 16 - Verify the Frame Relay PVC status for router Lab-B (the switch) Lab-A# ping 201.100.11.2 What was the result?