TROUBLE WITH FRAME-RELAY INITIAL CONFIGS  

Thursday, December 25, 2008

I WAS FACING TROUBLE WITH FRAME-RELAY CONFIGURATION AND COULDNT RECOLLECT IT .. I HAVE MADE A SMALL EFFORT TO REMEMBER SOME CORE CONCEPTS .. ENJOY IF ITS INTERESTING , ENJOY EVEN IF IT IS BORING wink.gif !.!.! 3 PACKET SUCCESS

#CONFIGURING FRAME-RELAY START(FRS) AND END POINTS

Configuration:

let us take this present situation where in we have 3 interfaces
s0/0 s0/1 s0/2 for frs and connected to other routers respectively

first we will go about configuring the framerelay switch or in our case making router as a frs

first , imagine that you are literally sitting on the interface s0/1 which connects to routers s0/0 and has dlci's 104 and 105

That router will be the hub and other two will be spokes with dlcis 501 and 401 for s0/2 and s0/0 interfaces respectively

Now imagine that you are on s0/1 of the frs and router a has thrown a packet for dlci 501 . as you are a frs you need to route that particular packet to that dlci

The first thing we will look after accepting packet for routing is
to route the packet or throw the packet to an interface which has
nearest target address

Next as we are on a frame-relay network we need to also see the
incoming dlci and also outgoing dlci by sitting on the router
interface .. its so much fun to sit on the network card and route
packets ....! (oops 4 packets missed) wink.gif

So , we see that packet is coming from a dlci 105 which needs to
be routed to 501 and it has a nearest interface of s0/2 that this frs connects to.

That's it you are done configuring it ... just remember these things

1. INCOMING DLCI
2. OUTGOING DLCI
3. NEAREST INTERFACE


interface Serial0/1
no ip address
encapsulation frame-relay
clock rate 2000000
frame-relay lmi-type cisco
frame-relay intf-type dce
frame-relay route 104 interface Serial0/0 401
frame-relay route 105 interface Serial0/2 501
!

now see here we are sitting on serial0/1 and a packet came begging.. we have considered it and accepted to route the packet to destination dlci 501 . the packet came from 105 dlci . after calculations or analysations we knew that s0/2 was very much near to the r5 or 501 dlci


Now similarly ,

how did router at hub knew that it should foreward packet to 501 dlci and to that particular ip ????

sit on router1 which is a hub and has two dlcis as it sees , 104 and 105

how could it see two dlci's .. or how could we see two dlcis from router 1 or hub .... sadistic laugh .. we have already configured
it ..!.. (oops middle packet was successful)

we need to map some of the dlci's to the ip addresses of the
remote routers . simple then whenever we want any thing to be forewarded to a ip we will foreward it to dlci and then dlci will take care . just and imagination

so , keep in mind route is word which is confined to frs and map is a word which is confined to the end points

interface Serial0/0
ip address 10.0.0.1 255.0.0.0
encapsulation frame-relay
no ip split-horizon eigrp 1
clock rate 2000000
frame-relay map ip 10.0.0.1 104
frame-relay map ip 10.0.0.4 104 broadcast
frame-relay map ip 10.0.0.5 105 broadcast
no frame-relay inverse-arp
!

as you can see whenever we want anything sent for 10.0.0.5 we want it go to dlci 105 which will then be converted by our frs .. a similar config should be done at r5 and bingo we can establish connectivity

I was confused with fr so though of putting it some or the other way .. though it needs some of the other configs these are the base level configs and should help you to reach to max without much of the confusion

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