mpls...

mpls is simple and straightforward to set up on a basic topology...

ip cef needs to be enabled, as well as mpls ip for each interface... mpls fundamentally does the rest...

set up four routers with eigrp and connect them, ensure eigrp is operational...

r4#sh ip eigrp topo
EIGRP-IPv4 Topology Table for AS(100)/ID(172.16.1.2)
Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
       r - reply Status, s - sia Status

P 192.168.23.0/24, 1 successors, FD is 30720
        via 172.16.1.1 (30720/28160), FastEthernet0/0
P 192.168.12.0/24, 1 successors, FD is 33280
        via 172.16.1.1 (33280/30720), FastEthernet0/0
P 172.16.1.0/24, 1 successors, FD is 28160
        via Connected, FastEthernet0/0

r3#sh ip eigrp neigh
EIGRP-IPv4 Neighbors for AS(100)
H   Address                 Interface              Hold Uptime   SRTT   RTO  Q  Seq
                                                   (sec)         (ms)       Cnt Num
1   172.16.1.2              Fa0/0                    13 00:21:44    1  4500  0  3
0   192.168.23.2            Fa1/1                    14 01:06:35   19   114  0  6

r4#sh ip route eigrp

Gateway of last resort is not set

D     192.168.12.0/24 [90/33280] via 172.16.1.1, 00:23:07, FastEthernet0/0
D     192.168.23.0/24 [90/30720] via 172.16.1.1, 00:23:07, FastEthernet0/0

the eigrp topology doesn't matter, just get them connected...

turn on


ip cef

for every connected interface add:

mpls ip

that's it...

r4#sh run int f0/0
interface FastEthernet0/0
 ip address 172.16.1.2 255.255.255.0
 speed auto
 duplex auto
 mpls ip
end

r3#sh mpls ldp neighbor
    Peer LDP Ident: 192.168.23.2:0; Local LDP Ident 192.168.23.3:0
    TCP connection: 192.168.23.2.646 - 192.168.23.3.18146
    State: Oper; Msgs sent/rcvd: 89/88; Downstream
    Up time: 01:12:10
    LDP discovery sources:
      FastEthernet1/1, Src IP addr: 192.168.23.2
        Addresses bound to peer LDP Ident:
          192.168.12.2    192.168.23.2   
    Peer LDP Ident: 172.16.1.2:0; Local LDP Ident 192.168.23.3:0
    TCP connection: 172.16.1.2.646 - 192.168.23.3.30237
    State: Oper; Msgs sent/rcvd: 37/36; Downstream
    Up time: 00:27:10
    LDP discovery sources:
      FastEthernet0/0, Src IP addr: 172.16.1.2
        Addresses bound to peer LDP Ident:
          172.16.1.2     

from:
http://www.cisco.com/en/US/docs/ios/12_2t/12_2t2/feature/guide/ldp_221t.html#wp1354663

MPLS Label Distribution Protocol (LDP), which enables peer label switch routers (LSRs) in an MPLS network to exchange label binding information for supporting hop-by-hop forwarding along normally routed paths

and all of this was simply for this... gotta see it... look for, the union label...

look at this link for mpls vpn... 

http://socketready.com/2011/03/05/mpls-configuration-guide/

i won't have time for that until this weekend; my vacation is over...  as my nana would say, "you do"...