Frame relay point to point config-help needed

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Dec 16th, 2008
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Hello all,

I need pointer to a link (I have already check cisco frame relay config documents on CCO) or document which will be able to provide info on how to configure frame relay point to point subinterfaces on R1, R2 and R3 where all three routers are connected to FR switch. Except for R1 which has two WAN links connected with FR switch, rest of the routers have only 1 WAN link.

I will be using OSPF for routing.

Thanks in advance

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Giuseppe Larosa Tue, 12/16/2008 - 12:52
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Hello Asim

int serx/y

encapsulation frame-relay

no ip address

int serx/y.M point-to-point

ip address yourwan.ipaddr mask

frame-relay interface-dlci DLCI#

router ospf 10

network yourwan wildcard area xxx

on point-to-point subifs OSPF run smoothly using point-to-point network type

the frame-rel interface-dlci DCLI#

refers to the DLCI to be used on the local router to reach the router on the other end

R1 will have two p-t-p subifs that can be on the same physical interface or one in each.

the subnet can be /30 because OSPF is classless.

You need to use two different /30 subnets one for R1-R2 logical link and one for R1-R3 logical link

Hope to help


asimkamran Tue, 12/16/2008 - 12:54
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Thanks Giuseppe.

How about config on the FR switch? Please advice.

Giuseppe Larosa Tue, 12/16/2008 - 13:07
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Hello Asim,

see the section frame-relay switching from 12.4 Wan Configuration guide

you need to enable frame-relay switching on the node at the global level

on each interface you need to have it behave like a FR switch port (change in FR LMI role)

frame-relay intf-type dce

skip the connect command is for ISDN (never used)

frame-relay route in-dlci interface out-interface-type out-interface-number out-dlci

you need to build the also the reverse path on the other interface to create a full duplex PVC

usually DCE layer1 (that follows cable type) and DCE L2 are on the same side

you can check cable type sensed with

sh controller ser x/y (it works on several platforms not all)


important: the interface with DCE cable has to provide clock with command

clock rate xxxx

Hope to help


sachinraja Tue, 12/16/2008 - 14:02
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Attaching a small file which has some config details.. configs will change based on the DLCI values assigned on the exit/entry interfaces..

Hope this helps you



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