[c-nsp] filter LDP bindings

Sergio D. sdanelli at gmail.com
Mon Aug 11 13:29:57 EDT 2008


This maybe of some value:

PE1#show mpls ldp bindings advertisement-acls
Advertisement spec:
        Prefix acl = 1

  tib entry: 1.1.1.0/30, rev 26
  tib entry: 1.1.1.4/30, rev 27
  tib entry: 10.0.0.1/32, rev 33
        Advert acl(s): Prefix acl 1
  tib entry: 10.0.0.2/32, rev 34
        Advert acl(s): Prefix acl 1
  tib entry: 25.25.25.25/32, rev 30
  tib entry: 150.0.0.0/24, rev 31
  tib entry: 160.0.0.0/24, rev 32

appears that the ACL catches the right prefixes.

On Mon, Aug 11, 2008 at 9:51 AM, Oliver Boehmer (oboehmer) <
oboehmer at cisco.com> wrote:

> Sergio,
>
> your config looks fine, so I don't know what's happening. Can you show a
> "show mpls ldp bindings 10.0.0.1 32" on the LDP neighbor(s) or a "show
> mpls forwarding interface <foo>" where <foo> is the neighbor's interface
> to PE1?
> No need to specify a "to <acl>" to select which neighbors you want to
> advertise this to in your case.
>
>        oli
>
> Sergio D. <mailto:sdanelli at gmail.com> wrote on Monday, August 11, 2008
> 4:52 PM:
>
> > thanks for the response.
> > I am using 12.3(22) and "no mpls ldp advertise-labels" turns into "no
> > tag-switching advertise-tags" which I already have.
> > Oliver,
> > thanks for clearing up the assignment of the label, I guess thats
> > fine as long as it doesn't get advertised which is what I am trying
> > to avoid. I did try it without the deny at the end, and the result
> > was the same.
> > Do I need an access-list listing my peers and apply that?
> >
> > TIA
> >
> >
> >
> > On Mon, Aug 11, 2008 at 2:24 AM, Paolo Lucente <pl+list at pmacct.net<pl%2Blist at pmacct.net>
> > <mailto:pl%2Blist at pmacct.net <pl%252Blist at pmacct.net>> > wrote:
> >
> >
> >       Hi Sergio,
> >
> >       to add to what Oliver said that you maybe want to make sure
> >       you have in the configuration a "no mpls ldp advertise-labels"
> >       line. Without that, even if you configure a filter (which is
> >       successfully matched as you shown), labels would still be
> >       announced to adjacent LDP peers.
> >
> >       Don't know if this could be your case; i did have to make use
> >       out of it to verify label filtering working on a 12.2SR while
> >       trying to minimize exposure of our labels in an "Inter-AS" L2
> >       MPLS VPN scenario.
> >
> >
> >       no mpls ldp advertise-labels
> >
> >       mpls ldp advertise-labels for LDP-DEST to LDP-PEER
> >       [ ... ]
> >       mpls label protocol ldp
> >       !
> >       interface Loopback0
> >        ip address 192.168.100.4 255.255.255.255
> >       !
> >       ip access-list standard LDP-DEST
> >        permit 192.168.100.4
> >       ip access-list standard LDP-PEER
> >        permit 192.168.100.1
> >       !
> >
> >       Cheers,
> >       Paolo
> >
> >
> >
> >       On Sun, Aug 10, 2008 at 09:50:34PM -0600, Sergio D. wrote:
> >       > Hello,
> >       > I am trying to filter LDP label bindings to only advertise my
> >       loopback > address(for vpnv4 traffic) but I am unsure as to what
> the
> >       requirements are. > Here is what I have:
> >       > PE1#show ip route connected | in ^C
> >       > C       1.1.1.0 is directly connected, Serial1/0
> >       > C       10.0.0.1 is directly connected, Loopback0
> >       > C       150.0.0.0 is directly connected, FastEthernet0/1
> >       >
> >       > PE1#sh run | in tag
> >       > no tag-switching advertise-tags
> >       > tag-switching advertise-tags for ldp-filter
> >       >
> >       > PE1#show access-lists ldp-filter
> >       > Standard IP access list ldp-filter
> >       >     10 permit 10.0.0.0, wildcard bits 0.0.0.255 (6 matches)
> >       >     999 deny   any (7 matches)
> >       >
> >       > matches?
> >       >
> >       > but still generates a binding for all my connected interfaces:
> >       >
> >       > PE1#show mpls ldp bindings 150.0.0.0 24
> >       >   tib entry: 150.0.0.0/24, rev 2
> >       >         local binding:  tag: imp-null
> >       >         remote binding: tsr: 25.25.25.25:0, tag: 18
> >       > PE1#
> >       >
> >       > And the other side tags it with a label:
> >       >
> >       > PE2#traceroute 150.0.0.1
> >       >
> >       > Type escape sequence to abort.
> >       > Tracing the route to 150.0.0.1
> >       >
> >       >   1 1.1.1.5 [MPLS: Label 18 Exp 0] 16 msec 52 msec 24 msec
> >       >   2 1.1.1.1 24 msec 52 msec *
> >       >
> >       > TIA,
> >       >
> >       > --
> >       > Sergio Danelli
> >
> >
> >
> >
> >
> > --
> > Sergio Danelli
>



-- 
Sergio Danelli
JNCIE #170


More information about the cisco-nsp mailing list