- Bronze, 100 points or more
Hi every body
I have few questions;
Let say we have three routers,r1,r2 and r3. All these routers are connected with with each other by frame relay . They are fully meshed as well.
Usually frame relay encapsulation is configured under physical interface. But i want to connect these routers using point-to multipoint int with frame relay encapsulation configured under it.
For example on r1
int s0/0.1 point-to-multipoint
The other two routers are configured in the similar manner. Can i do this?
2) Same scenario but this time i want to configure encapsulation using frame-relay interface-dlci command, with this stipulation in mind that no frame relay encapsulation is configured either under the physical or sub interface on each router.
For example on r1
int s0/0.1 point-to-multipoint.
frame-relay interface-dlci 54 ietf
frame-relay interface-dlci 65 ietf
Where 54 is dlci for vc b/w r1 and r2
while 65 is dlci for vc b/w r1 and r3.
Can i do this?
Thanks a lot and have a nice weekend.
Regarding the point-to-point subinterfaces and InverseARP: my experience is that a point-to-point subinterface does not send InverseARP requests by itself but accepts them upon receival and answers to them (it sends replies).
I agree this is necessary sorry I didn't write clearly in my post.
well well, you need still to have the frame-relay interface DLCI commands on the hubs and on the spoke, as detailed on my other post. That is the minimum FR config to get it to work.
Inverse-arp will take care of the ip addressing, but you need to say out of which DLCI it will go.
You need at least the following command on the main side that is using the multipoint interface:
frame-relay interface-dlci DLCI_TO_R1
frame-relay interface-dlci DLCI_TO_R2
Also on the point to point subinterfaces, you need 1 only frame-relay command:
frame-relay interface-dlci DLCI_TO_R3
Then it will work, I just tested it.
I had some doubts on the capability of a point-to-point subinterface to advertise the DTE IP address over the DLCI.
For sure inverse-ARP is disabled on the receiving direction.
Then I checked on the CCIE exam certification guide third edition book and I've found an example like your scenario: a hub router with multipoint subinterface and two spoke routers.
The example shows with debug frame-rel events that the spoke with point-to-point subinterface advertises its network layer address on the DLCI.
if so no static mappings are needed.
This is handy for production networks with a lot of spoke routers.
Hope to help
2) You should have encapsulation frame-relay under the physical interface to be able to configure your s0/0.1 with point-to-multiploint
no because enc frame-relay is not allowed in a subinterface you can specify the FR encapsulation per DLCI probably as an option in a frame-relay map command
yes frame-rel map supports the option for encapsulation
I never used frame-relay interface-dlci with multipoint subinterfaces but I think you can do it in this way or using frame-relay map command as I noted above.
command reference about frame-rel interface-dlci says:
>>This command is required for all point-to-point subinterfaces; it is also required for multipoint subinterfaces for which dynamic address resolution is enabled. It is not required for multipoint subinterfaces configured with static address mappings.
So yes to question 2
Notice that FR encapsulation must match on both DTE connected by the same PVC but it can be different on different PVCs on the same physical interface or multipoint subinterface.
Hope to help