[mpls-linux-general] binding label/FEC to hosts
Status: Beta
Brought to you by:
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From: krishnan n. <shy...@my...> - 2001-07-25 14:15:17
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Hello,
When the routing table contains net entries, say,
192.168.1.0, how do we set up a label/FEC mapping
to a specific host, say, 192.168.1.1?
Assuming we would want to create a Label Switch
Path to a specific host and also don't want to
make the the host routing entry in every LSR
in the path - the net entry to reach this host already
exists - how do we do it? Is it at all possible?
Currently, we are able to create FEC using the net
entry:
mplsadm -B ... -f 192.168.1.0/24
What we would like to do is to have a label to a host:
mpsadm -B ... -f 192.168.1.2/25
From the code (i'm on *very* shaky ground here) it looks
a bit hard to write host FEC to a n/w route in fib. Traced
it down to:
net/mpls/mpls_out_info.c: mpls_bind_out2fec
...
...
if(fib_add_proto_data(&k,&res,AUX_PROTO_DATA_MPLS) == 0) ...
and in:
net/ipv4/fib_hash.c:fn_hash_add_proto_data()
...
...
f->fn_proto_data[proto_num] = res->proto_data[proto_num];
/* ?? appears, only one proto data may be added per proto
num, even though fn_proto_data is declared *[] */
It appears to be easier to hold this FEC in the mpls_out_info
_tree list ?
I am curious to know:
a) Would it be useful to be able to bind a label to a host given
only a net entry in the routing table?
b) does the Forwarding Information Base semantics support this
at all?
c) Alternatively, does it make sense to map a net entry to a
host entry. What i mean is, if the user specifies a host
entry ( mplsadm -f 192.168.1.2/32 in the example above)
would it make sense to silently map this to 192.168.1.0/24?
since only 192.168.1.0 entry exists in the routing table?
d) (unrelated question) where can i get more information about the
kernel mutiple table support / Forwarding Information Base?
thank you,
shyam
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