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"frame-relay map" between spokes

zillah2004
Level 1
Level 1

The requirment for the scenario that I have got is this :

1- Using only physical interface configure a Frame Relay hub-and-spoke network between R33 (S1/1 ip address 182.1.0.33), R44 (S0/0 ip address 182.1.0.44), and R55, with R55 as the Hub (S0/0 ip address 182.1.0.55)

2- Traffic form R33 destined for R44 should transit R55 and vice versa.

3- R33 DLCI 33, R44 DLCI 44, R55 DLCI 55

4- Do not use any dynamic layer 3 to layer 2 mapping over these frame Relay connections.

5- Do not send any redundant broadcast traffic form the spokes to the Hub.

part of the configurations for both spokes R33 and R44 are :

R33 (spoke)

frame-relay map ip 182.1.0.44 33

frame-relay map ip 182.1.0.55 33 broadcast

R44(spoke)

frame-relay map ip 182.1.0.33 44

frame-relay map ip 182.1.0.55 44 broadcast

As you can see that from R33 (spoke) there is static frame relay map to R44 (spoke) and vice versa,,,,this is the reason for my thread in this forum.

With FR "Hub and Spoke" scenario, Can we have "frame-relay map" (my concern with static mapping ) command between two spokes ?

I knew that we should "frame-relay map" from each spoke to hub, and from hub to each spoke.

Note: I do not look for another way to solve the scenario.

16 Replies 16

devang_etcom
Level 7
Level 7

yes you can map the DLCI for the spoke. by using the same DLCI used for the communication with the HUB on both the router ...you have to just add only one command on both the spokes as follow

currently you have configure your topology in parital mesh and when ever you are going to map the dlci for the both the spoke router then you will have full mesh connectivity...

now just add only one command on both the spoke router as follow.

on R33

frame-relay map ip 182.1.0.44 33 broadcast

on R44

frame-relay map ip 181.1.0.33 44 broadcast

you will find good configuration examples on FR in CCIE practical studies vol-I by Karl solie...

hope this will help you

rate this post if it helps

regards

Devang

To my knowledge If I want to have full mesh, I should have had a DLCI from R33 to R44 and from R44 to R33 not through Hub, beside the current DLCIs,,,Am I right ?

But since these DLCIs (from R33 to R44 and vice versa not through Hub) are not available in the scenario above , how can I have full mesh ?

yes you are right at that time you need to have it...but as per your case you need to configure frame relay map as i had given before...what ever you used in you scenario its using the communication with HUB even when two router want to communicate with each other ...as it is cost effective solution other wise you need to have the more DLCI number in order to creat PVC between all router...mean full mesh...

hope this will help you

rate this post if it helps

regards

Devang

Thanks devang

1- Since the requirment for the scenario have used the term "Hub and Spoke"; that means we can not use full Mesh,,,,Am I right ?because "Hub and Spoke" is partially mesh (one point of failure

2- my understanding (correct me if I am wrong) to your explaination like this :

2/A- Since the requirment has not mentioned any DLCIs(because there are DLCIs via HUB) between R33 and R44,,,that means we can not have full mesh.

2/B- To overcome this problem (not having DLCIs between R33 and R44) in 2/A and to have full mesh configuration, we have to configure static map between spokes (R33 and R44),,,Am i right ? But this will contradict with 2/A

2/C- You said: ((but as per your case you need to configure frame relay map as i had given before))

As you can see in my early thread it has already been configured. I could not get what you meant by your quote above!!!!!.

Hello,

I believe something could be missing here.

Full mesh means that if you have 3 sites, you need 3 links [(3.2)/2= 3, 4 sites (4.3)/2=6]. In this case, the Frame-relay switch must be fully meshed, meaning you need more DLCI; or in your scenario 2 DLCI per router.

But what is being asked is: HUB-SPOKE using only physical interfaces, using map statements (no frame-relay inverse-arp).

with:

R33 (spoke)

int s0/0

ip address 182.1.0.33 255.255.255.0

encap frame-relay

no frame-relay inverse-arp

frame-relay map ip 182.1.0.44 33

frame-relay map ip 182.1.0.55 33 broadcast

R44(spoke)

int s0/0

ip address 182.1.0.44 255.255.255.0

encap frame-relay

no frame-relay inverse-arp

frame-relay map ip 182.1.0.33 44

frame-relay map ip 182.1.0.55 44 broadcast

You can make the spokes ping or communicate with eachother. Using a single dlci in each spoke.

BUT you need 2 dlci on the hub, in this case spoke routers would send traffic to the HUB and the HUB would foward traffic to the other spoke.

But with just 1 dlci in the HUB. I dont think this is possible.

I'd like to see how this is done.

If someone have the complete configs for this, let me know

vlad

btw,

with 2 dlci on the HUB

R(55)

int s0/0

ip address 182.1.0.55 255.255.255.0

encap frame-relay

no frame-relay inverse-arp

frame-relay map ip 182.1.0.44 554 broadcast

frame-relay map ip 182.1.0.33 553 broadcast

frame-relay map ip 182.1.0.55

you can have HUB-and-spoke with no problems. having a single dlci per spoke wont contradict any requirement.

see if you want to creat full mesh in you network then you need total 6 DLCI...

HUB router need 101 to communicate with one spokeA and 102 with other spokeB.

Spoke A need 201 to communicate with hub and 202 with spokeB.

spoke B need 301 to communicate with HUB and 302 with spokeA.

means to make communication with each and every device you need to have seperate DLCI for each router.

bye this way you can have full mesh...

hope this will help you

regards

Devang

((see if you want to creat full mesh in you network then you need total 6 DLCI...

bye this way you can have full mesh... ))

That is great, this is what I knew.

Now to my first query why did he create maps between spokes (not hub and spoke)?

Hello,

Do you have complete configuration for this? I dont think you can make hub-and-spoke with only 3 DLCI, I think you need 1 more on the HUB.

Vlad

(( I dont think you can make hub-and-spoke with only 3 DLCI, I think you need 1 more on the HUB.

))

Yes you are right , actullay there is one more associated with R55.

But i have not mentioned the whole information because my attention to know if we can have farme-relay map between spokes, and not between hub and spoke.

lest say spoke A and spoke B...which is connected with the HUB...when spoke A will receive any packet which is destine for the spoke B network then apoke A will send data to hub router with the DLCI configure to reach HUB...so frame-relay map on spoke A will tell the packet to use the XYZ DLCI to reach the spoke B router ...

hope this will clear you

rate this post if it helps

regards

Devang

Thanks Devang for your patient and conrtibution.

((lest say spoke A and spoke B...which is connected with the HUB...when spoke A will receive any packet which is destine for the spoke B network then apoke A will send data to hub router with the DLCI configure to reach HUB...so frame-relay map on spoke A will tell the packet to use the XYZ DLCI to reach the spoke B router ...))

As you can go through cisco documentations, there are many examples with Hub-and-Spoke topologies, many of these examples I have not seen they have used frame-relay map between spokes.

Please see the attachment for one of them

Why has the "frame-relay map" command been used here (with this scenario) ? Is there any hint in the requiremnet that i have posted here push me to do that ?

What is the difference between this sceanrio and the other scenarios (within cisco documentation) ?

http://www.cisco.com/en/US/products/hw/switches/ps700/products_configuration_example09186a008010f615.shtml

http://www.cisco.com/univercd/cc/td/doc/product/software/ios121/121cgcr/wan_c/wcdfrely.htm

and you can also see the book name i post in my first reply CCIE practical study vol I

hope this will help you

rate this post if it helps

regards

Devang

well well, now things start to make sense As you could see now we have 2 DLCI in the HUB. As its not possible to create hub-and-spoke with a single DLCI in the hub.

Using physical interfaces on the hub and not using the command:

frame-relay interface-dlci

you need to map the remote spoke IP in each spoke.

this is quite simple.

map statement means, to reach this IP go through thi DLCI, in this case you have only 1 (pointing to the hub)...

Hub router will receive this packet and foward toward the other spoke (using another dlci).

Hope, you read this,

Vlad

"Hope, you read this"

Sorry Vlad, there was delay in receiving your replies, or may be me and you we were posting in the same time.

As you see in my first early thread, I was looking to find out why is the "frame-relay map" command used from spoke to spoke,in this Hub-and-Spoke topology, while in other Hup-and-Spoke topology (attachment) is not used ? I was not looking to involve full mesh (as you said to find number of links n(n-1)/2), because if you involve full mesh, we will concentare on it,and leaving the origin question, though the requirment of the sceanrio is HUP-and-SPOKE.

"Hub router will receive this packet and foward toward the other spoke (using another dlci)".

That means in the Hub-and-Spoke (Hub is point of failure) topology if the hud is responsible for receiving a packet from a spoke and forward toward another spoke, I do not need to create map (i meant static map) between spokes, yes i do need to create map (i meant static map) between spoke and hub,,,Am I right,,,I hope you got where is my point?

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