Full Mesh Frame Relay

cnfuzzd

I have a quick question about the topic.

The sim im running has four routers, all with 3 point-to-point sub-interfaces connecting to each of the three other routers. My questions are:

Im in the way of thinking that dlci's are only significant locally, so it doesnt matter what value i actually assign when using the frame-relay interface-dlci <> command. is this correct?

Does the order i assign either dlci's or ip addresses to sub-interfaces. matter. Obvious, my logical addresses will be on the appropriate segment (172.16.4.1 on the same line as 172.168.4.2) but i am still encountering some resistance on getting two of my connections to go. Does serial int 0.100 on router 1 with ip address of 172.16.4.1 need to correspond to its directly connected neighbors serial int 0.100 with an ip address of 172.16.4.2?

I think i may not be very clear, just yell at me a bit, and i will try to explain further.


peace

john nickle

Netstudent

m in the way of thinking that dlci's are only significant locally, so it doesnt matter what value i actually assign when using the frame-relay interface-dlci <> command. is this correct?

That is correct, you just have to be aware of the DLCI's when you create a frame-relay switch.

Does the order i assign either dlci's or ip addresses to sub-interfaces. matter

no it doesn't matter what order the numbers are. Just as long as you can keep track to what DLCI's are where.

Does serial int 0.100 on router 1 with ip address of 172.16.4.1 need to correspond to its directly connected neighbors serial int 0.100 with an ip address of 172.16.4.2?

each p-t-p subinterface will be a it's own subnet. So 172.16.4.0/30 would be one subnet for the first subinterface.

rjbarlow

cnfuzzd wrote:

I have a quick question about the topic.

The sim im running has four routers, all with 3 point-to-point sub-interfaces connecting to each of the three other routers. My questions are:

Im in the way of thinking that dlci's are only significant locally, so it doesnt matter what value i actually assign when using the frame-relay interface-dlci <> command. is this correct?

Does the order i assign either dlci's or ip addresses to sub-interfaces. matter. Obvious, my logical addresses will be on the appropriate segment (172.16.4.1 on the same line as 172.168.4.2) but i am still encountering some resistance on getting two of my connections to go. Does serial int 0.100 on router 1 with ip address of 172.16.4.1 need to correspond to its directly connected neighbors serial int 0.100 with an ip address of 172.16.4.2?

I think i may not be very clear, just yell at me a bit, and i will try to explain further.


peace

john nickle

Eh, dear friend, You will have pretty much time to spend to grasp basis of Frame Realy...
First: ever a DTE in F.R. is "directly connected" to another DTE. It is only directly connected to a F.R. Switch.
Then I tell You that:
- DLCIs are carried to the DTE by means of LMI messages directly from the attached F.R. switch. Start from this point, is quite good.
- Second trouble is mapping DLCI/IP address, because even if the DTE know some DLCI it don't know what DLCI and IP address put into the same frame, in order to reach the "other-end" DTE on a PVC.
- You tell about a Full meshed F.R. network, this means that there are subinterfaces point-to-multipoint. The concepts: point-to-point and point-to-multipoint in F.R. in fact are closely related to the IP addressing scheme of the network.
- Because You use point-to-multipoint subinterfaces, then You don't need "interface-dlci" command, because Inverse ARP provides mapping. That command is more appropriate for a point-to-point subinterface on which Inverse ARP is disabled by default.
- Rather then use Inverse ARP, You can use static mapping with the command "frame-relay map".

Finally DLCIs locally significant don't means that You always must to do strange things in the configurations, it only means that DLCIs can't be replied on the same DTE because one DLCI is indicating one only PVC. Remember that DLCIs are carried by LMI.

Hope this will help You in some way.