How to use a Cisco router as Frame-Relay switch

For this tutorial you can use  a low cost Cisco router and of course you need some serial interfaces available on this router. I will use a 7206 with 3 serial interfaces. This router I will call R6 and the rest of the three routers connected to R6, will be R2, R5 and R9. In this way it will be easier for you to understand how the frame-relay routing is achieved.

If we have a look to R6’s (the router used as frame-relay switch) interfaces:

r6-c7206#sh int desc
Interface                      Status         Protocol       Description
Fa0/0                            up                down
Fa0/1                             up                down
Se5/0:1                         up                up                    TO_R2
Se5/1:2                         up                up                    TO_R5
Se6/0                            down          down
Se6/1                             up                up                    TO_R9

you’ll notice that we have 3 active serial interfaces, each being connected to one of the three routers R2, R5 and R9.

Very important, before you begin define a scalable range for your DLCI numbers, otherwise you will have a complete mess when troubleshooting is needed. I like to define them after formula Rx0Ry. In the middle you have the number zero. In this idea, we will have something like R20R5 and from this resul the DLCI 205 for the Frame-Relay connection between R2 and R5. Below you have the DLCI numbers used in this tutorial:

R2 -> R5: DLCI 205
R2 -> R9: DLCI 209
R5 -> R2: DLCI 502
R5 -> R9: DLCI 509
R9 -> R2: DLCI 902
R9 -> R5: DLCI 905

Now that we have defined the DLCI numbers lets configure R6 router as frame-relay switch.

First of all, you need to enable frame relay switching on the router:

r6-c7206#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
r6-c7206(config)#frame-relay switching

This command enable the switching  of packets based on the data?link connection identifier (DLCI) inside your router.

Next, we have to configure the frame-relay routing on the physical interface. We will start with interface S5/0:1 where R2 router is connected and apply the following configuration

interface Serial5/0:1
description TO_R2
no ip address
encapsulation frame-relay
! the frame-relay switch is the DCE and the other end is the DTE
frame-relay intf-type dce
frame-relay route 205 interface Serial5/1:2 502
frame-relay route 209 interface Serial6/1 902

With frame-relay route command we tell to frame-relay switch where to forward the packets based on the DLCI number. If we take a look to the first frame-relay route command, than the path to DLCI 502 is interface Serial5/1:2. If you feel confuse, please check again above the interface connection to the router and the assigment scheme for DLCI numbers.

The same like for interface S5/0:1, we will configure the interfaces connected to R5 and R9:

interface Serial5/1:2
description TO_R5
no ip address
encapsulation frame-relay
frame-relay intf-type dce
frame-relay route 502 interface Serial5/0:1 205
frame-relay route 509 interface Serial6/1 905

interface Serial6/1
description TO_R9
no ip address
encapsulation frame-relay
frame-relay intf-type dce
frame-relay route 902 interface Serial5/0:1 209
frame-relay route 905 interface Serial5/1:2 509

Having a look to S5/1:2, first frame-relay route command, here we configure the path back from R5 to R2, by telling the frame-relay switch to chose interface S5/0:1 to send packets to DLCI 205 (R2).

This is the basics of how to configure a Cisco router as a frame-relay switch. If you need help, please don’t hesitate to use the comment form below.

CCIE R&S V4.0 Written: Beta Exam Announcement

The beta version of CCIE Routing and  Switching Written Exam v4.0 (351-001) is available for scheduling at all worldwide,  Cisco-authorized Pearson VUE testing centers starting August 7, 2009 and continuing  through September 9, 2009.

Nevertheless the number of beta exams is limited, so as soon as all the seats are taken this beta test period will end, even if this is before September 9, 2009.

Candidates may schedule and take the exam on the same day.  The beta exam will be offered at a discounted price of US$50, with full recertification or lab qualification credit granted to all passing candidates.

Another point to keep in mind is that the results will be received six to eight weeks after the close of the beta period. Therefore, CCIEs in suspended status with an expiration date before November 30, 2009 should recertify using another exam. Candidates may only attempt a beta exam once during the beta period.

More information about the steps to register for exam, you can find on The Cisco Learning Network website.

Two CCIE R&S Certification Webinars


Cisco will conduct two webinar events on Wednesday, May 20, 2009 to describe recent enhancements to CCIE R&S certification and Cisco 360 Learning Program for CCIE R&S.
Attendees can choose from calls at 8:00 am and 7:00 pm PST.
Participants need only attend one event as content will be identical.

Registration information is as follows:


Meeting Name: CCIE R&S Refresh
Date/Time: 5/20/2009 @ 8:00 AM and 7:00PM US/Pacific Time
Length: 90 minutes
Frequency: Once
Meeting ID: 222333

Register for each event:

Please visit to register for this event.

Join the Voice Conference

1. Call MeetingPlace:

Toll-free (US only): 1-800-370-2618

Toll-free (Canada only): 1-800-370-2618

International Direct Dial: 1-650-599-0315

2. Press 1 to attend a meeting.

3. Enter Meeting ID (222333) followed by the # key.

4. Follow the prompts to record your name and enter the meeting.

Join the Web Conference

1.    Disable any pop-up blocker software.

2.    Go to

3.    Enter meeting ID (222333) and click Attend Meeting.

4.    Enter your first and last name in the My name is box and click Attend Meeting.

5.    Answer Yes to any security warnings you receive and wait for the Meeting Room to initialize.

Please read more on: