[mpls-linux-general] RE: Label Mapping Initial call back

[Murali K. P. <mur...@mi...>]

Hi jim,
         I have question regarding the reply you had given me earlier.

Now saying this, there are many ways an LSR running LDP will fit into an

MPLS network.  Currently Juniper runs "the smart mans LDP" which means
that
it only distributes a label for the LSR id in unsolicited mode.  The
result is
instead of distributing labels for every route in the internet routing
table (~90,000) each LSR will only initiate one label mapping.  After
all of
the LSRs in the network have done this, the result will be the minimal
full
mesh of LSPs proving reachability across the MPLS core.  Using BGP or
other means allows you to map the entries in the routing table to these
LSPs.

Cisco runs in vanilla LDP mode, which means it distributes label (in
either
unsolocited OR on demond) for every entry in its forwarding tabel which
is
is willing to act an ingress for.



My understanding of the smart mans LDP is :

If each LSR sends label mapping only  for its own LSR ID. Then the label
table will have two columns FEC and OUTLABEL at each LSR. If LSP is
setup then there will be INLABEL column also included.
	Now if a packet is received then LSR will look up the routing
table get the next hop for the destination and then try to map the
destination address to the FEC and then get the OUTLABEL and do the
necessary modification to the packet.
so the flow will be some thing like this. Correct me if i am wrong.

DEST ->   FEC -> OUTLABEL=20

can you give me some pointers to "the smart man's LDP"



another question :

setup for testing ldp_linux

            eth0 connected via intranet                           eth0
 	LSRA
-------------------------------------------------------------  LSR B
  (ip address of A is 172.20.22.151)
(ip address of A is 172.20.22.58)


  Routing Table at A
Routing table at B is also similar to A
Dest           gateway        mask                 interface=20
172.20.22.58  172.20.22.58   255.255.255.255  UGH   eth0
172.20.22.151 172.20.22.151  255.255.255.255  UGH   eth0


So now i have run the above setup with the following sequence of CLI
commands

set trace 0xffffffff
add debug
add global 172.20.22.151 (correspoding 172.20.22.58 on B)
add interface eth0

Now my problem is that i am receivng label mapping for LSR B . But at
LSR A end it sends no route notifcation to LSR B saying that it cannot
send the label mapping for 172.20.22.151. Both sides are not exchanging
label mappings and it is happening only from one side.

I am attaching the output file stored at LSR A end. kindly help me out.

thanks in advance=20

murali krishna P.






 <<jlieu.ouput.txt>>=20