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| Question: I have a full T1 connecting two sites (Site A and Site B) with a DLCI of, lets say 100 for Site A. I have a third site (Site C), that is going to have a frame-relay connected to Site A. I was told that the DLCI for site C would be, say 110. I was also told that the DLCI for Site A would be 100 for this connection to the frame-relay. How is this possible since Site A already has a DLCI configured for 100 for the full T1? | |
| ChrisDfer 2004-02-13, 12:30 am |
| quote:
Originally posted by Dude
Question: I have a full T1 connecting two sites (Site A and Site B) with a DLCI of, lets say 100 for Site A. I have a third site (Site C), that is going to have a frame-relay connected to Site A. I was told that the DLCI for site C would be, say 110. I was also told that the DLCI for Site A would be 100 for this connection to the frame-relay. How is this possible since Site A already has a DLCI configured for 100 for the full T1?
I'm kinda retarded so I am having a hard time visualizing the mappings hehe maybe write them in a table type form so simple minds such as mine can see exactly what you mean. I am a moron  | |
| peterd 2004-02-13, 3:43 am |
| Hello,
the DLCI refers to the 'local' end of the circuit only. The bit in the middle, the service providers 'cloud' has completely different and separate circuit numbers.
So it's possible to have the same DLCI's at many of your sites, or each site can have different DLCI's for each circuit.
Hope that makes sense.
Peter | |
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| Yeah, it does Peterd, but it looks like that the existing T1 has a DLCI of, say 100 now. And now for the new frame-relay, they have assigned a DLCI of 100 for it. Just not sure on how I need to approach this configuration of DLCI on the router that already has that DLCI. Any idea? | |
| ChrisDfer 2004-02-13, 2:02 pm |
| Are they going over to two different frame relay networks(connecting to two seperate frame relay switches)? | |
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| Not sure, Shouldnt be at site A, since its the same site. Probably is different at site b and c. | |
| larkspur 2004-02-13, 9:47 pm |
| The T1 at Site A is frame relay right? If so, have you heard of PVC's? This is the same DLCI can be used. Also 2 different frame relay switches. Check out Cisco for more info on frame relay. | |
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| This DLCI thing is driving me freaking crazy! If its only "locally significant", why do you even need to configure it??? It doesnt make any sense. Plus, if you already have a DLCI of a certain number to that router, why in the heck would a carrier assign the same DLCI number to a different circuit??? No sense to this at all... | |
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| See, this is what I am talking about. This is a cut and paste from an education web site: "In the basic Frame Relay specification, DLCIs are 'locally significant' (connected devices might use different values to specify the same connection)."
So, if the connected router that I guess belongs to an ISP or such, could have a different value, then why do you need a local DLCI??? That doesnt make sense to me. What is that all about??? | |
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| Again, another cut and paste. Does this mean the ISPs router? : "In the LMI extended specification, DLCIs are 'globally significant' (DLCIs specify individual end devices). "
Does that mean that the ISPs (or carrier) router uses and extended specification of LMI? Does your company router not use an "extended spec" of LMI???
Sorry, this just doesnt make sense. Why do you need to configure it if the carrier may or may not even use it??? | |
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| can you even have two DLCIs that are the same??? | |
| larkspur 2004-02-20, 9:58 pm |
| Yes and NO. Sorry for the late response have been busy with software audits. If we drop a frame crkt in Tennessee and one in Cali. Then the circuits will be using 2 DLCI's 101 assigned to Tenn. and 102 assigned to Cali. Now we are expanding and add a company in Texas. We assign that Crkt DLCI 102. Now we have used the same DLCI. The circuits will be using different frame switches but now you have 2 pvc's. So basiclly logicaly two different circuits. If they were to go through the same Frame switch than then it would still eb ok because you have PVC. Check out the diagram. Am I understanding the question? | |
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| Almost, I wanted to know if you could have the same dlci for both circuits in Tenn.? 101 for the one in Cali, and 101 for the one on Texas, for the site in Tenn? | |
| larkspur 2004-02-22, 8:16 pm |
| I believe the answer to be yes. So Frame use Inverse ARP and also since you have PVC's the circuits are virtual and there fore you can have more than one circuit using the same dlci numbers. If you are not confident in my reply you could also ask this question in te CCNP forum.
Later |
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