Re: [mpls-linux-general] [mpls example]another question

[James R. L. <jl...@mi...>]

First, you need to work on your ascii-art-foo a bit :-)
-don't use tabs
-use a 80 column, fixed font, text editor (vi, emacs)

I've cleaned up your drawing:
 =20
                        192.168.101.0/24               192.168.103.0/24
                               |                              |
                               |                              |
 ------eth0    eth0------eth1  v  eth1----eth0  eth0---eth1   v   eth1------
| HostA |--------| LER1  |---------|  LSR  |-----|  LER2 |----------| HostB=
 |
 ------.10  ^   20-------20        30-----30  ^  40-----40          50------
            |                                 |
            |                                 |=20
      192.168.100.0/24                  192.168.102.0/24


Comments in-line...

>  Configuration
>  =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D
>   HostA
>  ------
>  ip route add 192.168.103.50/32 via 192.168.100.20
>=20
>  LER1
>  ------
>  mpls nhlfe add key 0 instructions push gen 1000 nexthop eth0 ipv4 192.16=
8.100.20
>  ip route add 192.168.103.50/32 via 192.168.101.30 spec_nh 0x8847 0x2
>  mpls labelspace add dev eth1 labelspace 0
>  mpls ilm add label gen 1002 labelspace 0
>  mpls xc add ilm_label gen 1002 ilm_labelspace 0 nhlfe_key 0x2

No XC required.  At the simplest level XCs are used for
labelswaping, therefor they are not used on LERS.

>  LSR
>  -----
>  mpls nhlfe add key 0 instructions push gen 1000 nexthop eth0 ipv4 192.16=
8.102.40
>  mpls nhlfe add key 0 instructions push gen 1002 nexthop eth1 ipv4 192.16=
8.101.20
>  ip route add 192.168.103.50/32 via 192.168.102.40 spec_nh 0x8847 0x2
>  ip route add 192.168.100.10/32 via 192.168.101.20 spec_nh 0x8847 0x3
>  mpls labelspace add dev eth0 labelspace 0
>  mpls labelspace add dev eth1 labelspace 0
>  mpls ilm add label gen 1000 labelspace 0
>  mpls ilm add label gen 1002 labelspace 0=20
>  mpls xc add ilm_label gen 1000 ilm_labelspace 0 nhlfe_key 0x2
>  mpls xc add ilm_label gen 1002 ilm_labelspace 0 nhlfe_key 0x3

No need for the 'ip route' statements.  You're labelswaping here, the
packets will never leaves the MPLS stack, therefore they will never see
the IPv4 routing table.

>  LER2
>  -----
>  mpls nhlfe add key 0 instructions push gen 1002 nexthop eth1 ipv4 192.16=
8.103.40
>  ip route add 192.168.100.10/32 via 192.168.103.40 spec_nh 0x8847 0x2
>  mpls labelspace add dev eth0 labelspace 0
>  mpls ilm add label gen 1000 labelspace 0
>  mpls xc add ilm_label gen 1000 ilm_labelspace 0 nhlfe_key 0x2

Again no XCs on LERs.

>  HostB
>  ------
>  ip route add 192.168.100.10/32 via 192.168.103.40
--=20
James R. Leu
jl...@mi...