frame relay question!!

Unanswered Question
May 16th, 2012

hello everyone,

I've been looking everywhere but can't seem to find the answer.

I am taking my ccna exams in a month's time and I am currently learning about frame-relay.

I have been looking everywhere but how do I know the DLCI that has been assigned to my local router? I know about using several show command e.g. show frame map, show fram lmi, show frame pvc , show run etc. but these only show the DLCI of the REMOTE routers.

I guess my question stems from if there is already a preconfigured and fully operating frame-relay router being used and I as a new engineer wants to know the DLCI that is assigned to it, how do I know. I mean are there some other show commands that I have missed or is it a case of me contacting my service provider to know?

Thanks.

I have this problem too.
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John Blakley Wed, 05/16/2012 - 03:59

The "sh frame-relay map" will show you what your local dlci is as well as "show frame-relay pvc":

R3#sh frame-relay pvc

PVC Statistics for interface Serial0/0 (Frame Relay DTE)

              Active     Inactive      Deleted       Static

  Local          1            0            0            0

  Switched       0            0            0            0

  Unused         0            0            0            0

DLCI = 103, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial0/0

  input pkts 17            output pkts 27           in bytes 1100     

  out bytes 1592           dropped pkts 0           in pkts dropped 0        

  out pkts dropped 0                out bytes dropped 0        

  in FECN pkts 0           in BECN pkts 0           out FECN pkts 0        

  out BECN pkts 0          in DE pkts 0             out DE pkts 0        

  out bcast pkts 1         out bcast bytes 34       

  5 minute input rate 0 bits/sec, 0 packets/sec

  5 minute output rate 0 bits/sec, 0 packets/sec

  Shaping adapts to BECN

  pvc create time 00:10:21, last time pvc status changed 00:10:01

Show frame-relay map:

R3#sh frame-rel map

Serial0/0 (up): ip 172.23.0.2 dlci 103(0x67,0x1870), dynamic,

              broadcast,, status defined, active

interface Serial0/0

ip address 172.23.0.3 255.255.255.0

encapsulation frame-relay

no fair-queue

clock rate 64000

frame-relay traffic-shaping

frame-relay interface-dlci 103

  class Cisco

HTH,

John

Cadet Alain Wed, 05/16/2012 - 04:00

Hi,

sh frame map and sh frame pvc will show you the dlcis used on the router where you apply the commands.

Regards.

Alain

tshekediwalker Wed, 05/16/2012 - 04:35

Thanks guys,

but I thought this command:

" DLCI = 103, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial0/0"

show the DLCI of the a remote router, in other words a router that I have formed a PVC relationship with.

So in this example dlci 103 will be the dlci of a different route. hence, I am able to to create a map if needed?

Cadet Alain Wed, 05/16/2012 - 04:39

Hi,

the DLCI you see here is the DLCI affected to the router by the Frame-relay switch through LMI and it will be used to reach distant prefixes.

Regards.

Alain

Richard Burts Wed, 05/16/2012 - 05:16

It is a common mistake to believe that the DLCI that you see in commands such as show frame-relay pvc is the remote DLCI. But the DLCI shown in the command is in fact the local DLCI.

HTH

Rick

tshekediwalker Wed, 05/16/2012 - 05:13

Hi Cadet Alain,

Thanks once again. I don't want to sound dumb or question your knowledge but according to the photos I have attached below (sorry if not the best quality) it is different to what you are telling me. The photos are from ccna icnd 2 book.

From the first photo we see the network diagram with 4 routers (of course in multipoint). I can see that altanta has dlci 51, charlotte dlci 52, nashville dlci 53 & boston dlci 54.

The second photo shows the output from Atlanta "show frame-relay pvc" command. from this I can see all the dlcis for the other three routers who have now formed a pvc relationship with Atlanta.however, the output does not show atlanta's own personal DLCI.

So what I am really asking is assuming  we didnt know from the photos that atlanta is is using dlci51 how will we ever know? and in a real world scenario i might be new to company and need to log into a local router to find its own personal dlci. how can i know?

Thanks for your patience.

Richard Burts Wed, 05/16/2012 - 05:22

It is a shame when books like this make a mistake. But the page that you show is not correct. Does the book include the configuration for that example in addition to the show command output? It might be helpful to see the configuration and if we did it might help to clarify the situation.

HTH

Rick

Richard Burts Wed, 05/16/2012 - 05:45

Thank you for the additional information. The configuration is quite plain and does clearly show what is going on. The interface command frame-relay interface-dlci n defines the local DLCI. And it makes it quite clear that what is in the drawing does not match what is in the configuration. On Atlanta the DLCIs are 52,  53, and 54. And these are the local DLCI values and not the values on the remote routers as shown in the drawing.

HTH

Rick

burleyman Wed, 05/16/2012 - 06:28

I just checked the brand new book out this year by Wendell Odom, CCNA ICND2 3rd edition and it has the exact same config and diagram as shown above (now Chapter 16).

Could you post how it should be configured.

Mike

Richard Burts Wed, 05/16/2012 - 06:46

I would say that there is not any problem with how it is configured, which should work quite well. The problem is with the drawing which seems to show 52, 53, and 54 as part of the remote routers and shows only 51 as associated with Atlanta router. When you look at the configuration and at the output of the show commands it is clear that there are 3 DLCIs on Atlanta and probably only one on the three remote routers. So change the drawing and all would be well.

HTH

Rick

John Blakley Wed, 05/16/2012 - 06:56

According to the configs, this is the way that the drawing should look:

tshekediwalker Wed, 05/16/2012 - 05:37

I have attached the configs below. Sorry for quality once again. I am using my iphone for this.thanks

      

tshekediwalker Wed, 05/16/2012 - 07:12

i had forgotten one of the config photos from my post at 08:10. I have now edited and attached the photo.

paulstone80 Wed, 05/16/2012 - 08:03

I have that book and used it for my CCNA exams. The content IS correct.

What it tells you is that the DLCI values shown are the Global DLCIs, what you need to configure Frame Relay are the Local DLCIs.

Global DLCIs are a bit misleading, but basically all you need to know is:

If a Global DLCI is shown, the router on the other end of that PVC use that Global DLCI as its Local DLCI.

From Mr Wendell himself: http://www.ccnaskills.com/2011/05/23/fr-answer-iii-global-dlcis/

And a pretty picture to illustrate the point!


burleyman Wed, 05/16/2012 - 09:03

Great explainations.... 5's for all.

I don't work with Frame relay at all and it has been awhile when I did them in my studies. All this information was great. I might just do some lab work to get this drilled in.

Mike

John Blakley Wed, 05/16/2012 - 12:10

Thanks Mike...I had to lab this up because I was curious

Okay..I started think about how the image is presented. I believe what they've done in the book is show the OPPOSITE DLCI. In other words, your Atlanta router will send to DLCI 51, but that's not the local dlci. The local dlci for that circuit is 54. I labbed this up above and it does work...with almost the same configurations as what's in your book:

R1:

interface Serial0/0

no ip address

encapsulation frame-relay

clock rate 2000000

!

interface Serial0/0.52 point-to-point

ip address 192.168.13.1 255.255.255.0

frame-relay interface-dlci 52

!

interface Serial0/0.53 point-to-point

ip address 192.168.14.1 255.255.255.0

frame-relay interface-dlci 53

!

interface Serial0/0.54 point-to-point

ip address 192.168.15.1 255.255.255.0

frame-relay interface-dlci 54

!

--- R2 is the FR Switch ---

R3:

interface Serial0/0

ip address 192.168.13.3 255.255.255.0

encapsulation frame-relay

clock rate 2000000

frame-relay interface-dlci 51

end

R4:

interface Serial0/0

ip address 192.168.14.4 255.255.255.0

encapsulation frame-relay

clock rate 2000000

frame-relay interface-dlci 51

end

R5:

interface Serial0/0

ip address 192.168.15.5 255.255.255.0

encapsulation frame-relay

clock rate 2000000

frame-relay interface-dlci 51

end

However, to your original question of getting the local DLCI, our other answers still stand:

On R4:

R4#sh frame-relay map

Serial0/0 (up): ip 192.168.14.1 dlci 51(0x33,0xC30), dynamic,

              broadcast,, status defined, active

R4#

R4#sh frame-relay pvc

PVC Statistics for interface Serial0/0 (Frame Relay DTE)

              Active     Inactive      Deleted       Static

  Local          1            0            0            0

  Switched       0            0            0            0

  Unused         0            0            0            0

DLCI = 51, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial0/0

On R1, this is what you'll see:

R1#sh frame-relay pvc | inc DLCI

DLCI = 52, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial0/0.52

DLCI = 53, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial0/0.53

DLCI = 54, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial0/0.54

R1#

HTH,

John

anthony.kellar Wed, 05/16/2012 - 19:35

This one bugged me too...look at it this way...you will never see the remote dlci on your router...they are always local.

Sent from Cisco Technical Support iPad App

burleyman Thu, 05/17/2012 - 04:32

What if you tried running the command...

show frame-relay route

That should show the Input DLCI and the output DLCI

Mike

tshekediwalker Thu, 05/17/2012 - 05:28

Oh my word. Think this is what I am looking for all along! I am using packet-tracer  and the show frame relay command only gives you lmi, pvc and map.!!!

thanks burleyman

Cadet Alain Thu, 05/17/2012 - 23:54

Hi,

Don't forget this command only works on the router acting as Frame-relay switch not on the DTE devices( end routers).

Regards.

Alain.

tbogie_gvds Sat, 05/26/2012 - 08:42

Folks,

This is the most illuminating article I have ever read as I too have struggled for a long time to understand why diagrams are drawn one way, the show commands say another and the command reference says something that whilst true (one would hope!) didn't match what I was seeing in the books compared to what I was seeing on the CLI.  So Thankfully you guys have put it all in such a way that I for the first time trully understand how to interpret the whole show.

Wow, Thanks!

I do need to also say that technically Odom is correct in his books.  One thing he does write about is the kind of addressing that is used in diagrams - local versus global - so we shouldn't be to hasty in selling him short.  The issue is that it could have been explained better in the book, which unfortunately took an article on a website to explain a little more thoroughly but still not that great in my opinion, but in reality for me it took j.blakley and paulstone80 for me to see the light.

Thanks Guys.

Timothy

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Posted May 16, 2012 at 3:12 AM
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