[j-nsp] Difference between "ldp egress-policy" and "ldp export|import"

[Thiago Drechsel]

Hi list.

A quick question: What's the difference between "ldp egress-policy" and "ldp
export|import".

After reading (release 8.5)
http://www.juniper.net/techpubs/software/junos/junos85/swconfig85-mpls-apps/id-80457.html#id-80457
http://www.juniper.net/techpubs/software/junos/junos85/swconfig85-mpls-apps/id-23057.html#id-23057

I understand that "egress-policy" is used to filter routes announced by the
router itself (the router is the origin), and "export/import" is used to
filter routers sent by other nodes. Is this correct??

Thanks in advance.

Thiago

[Mark Tinka]

Post by Thiago Drechsel
A quick question: What's the difference between "ldp
egress-policy"...

This one tells the router to determine which prefixes should
be announced into LDP.

With this command unconfigured, only the Loopback address is
announced into LDP. If you would like to announce other
prefixes, e.g., static routes, direct routes, e.t.c., you
would use this feature to do so.

Note: your egress policy list should contain your Loopback
address; if it doesn't, your Loopback address won't be
announced into LDP anymore.

Post by Thiago Drechsel
and "ldp export...

This one tells the router to determine which label bindings
to announce to its LDP neighbors. These labels represent
prefixes, i.e., label bindings (to prefixes).

For instance, if label 20000 is bound to prefix
192.168.0.1/32 and label 30000 is bound to prefix
192.168.0.20/32, you can setup an export filter that blocks
192.168.0.1/32 from being announced. This will cause the
router not to announce label 30000, but still announce label
20000.

Note: even though you may be able to prevent some bindings
from being announced to the router's LDP neighbors,
those same bindings can still be used by the local
router as a valid LSP.

Post by Thiago Drechsel
|import".

This works in the reverse of 'export', as above.

Note: the difference with the 'export' feature is that you
would still see the label binding for the prefixes
that have been filtered, in LDP; however, the router
will not consider said binding as a usable LSP.

Hope this helps.

Cheers,

Mark.
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