Comments on: MPLS LDP-IGP synchronization http://www.hauwaerts.be/2009/02/22/mpls-ldp-igp-synchronization/ The whole truth and nothing but the truth! Mon, 17 May 2010 21:03:47 +0000 http://wordpress.org/?v=2.9.2 hourly 1 By: Geert http://www.hauwaerts.be/2009/02/22/mpls-ldp-igp-synchronization/comment-page-1/#comment-306 Geert Fri, 06 Mar 2009 11:50:05 +0000 http://www.hauwaerts.be/?p=766#comment-306 Traffic will be routed over an alternate IGP path. In detail: when LDP is not "fully operational" (see below) on a given link, the IGP will advertise the link with maximum cost to avoid any transit traffic over it. In the case of OSPF, this cost is LSInfinity (16-bit value 0xFFFF), as proposed in [RFC3137]. In the case of ISIS, the maximum metric value is 2^24-2 (0xFFFFFE). Indeed, if a link is configured with 2^24-1 (the maximum link metric per [RFC5305]), then this link is not advertised in the topology. It is important to keep the link in the topology to allow IP traffic to use the link as a last resort in case of massive failure. Traffic will be routed over an alternate IGP path.

In detail: when LDP is not “fully operational” (see below) on a given
link, the IGP will advertise the link with maximum cost to avoid any
transit traffic over it. In the case of OSPF, this cost is
LSInfinity (16-bit value 0xFFFF), as proposed in [RFC3137]. In the
case of ISIS, the maximum metric value is 2^24-2 (0xFFFFFE). Indeed,
if a link is configured with 2^24-1 (the maximum link metric per
[RFC5305]), then this link is not advertised in the topology. It is
important to keep the link in the topology to allow IP traffic to use
the link as a last resort in case of massive failure.

]]> By: shivlu jain http://www.hauwaerts.be/2009/02/22/mpls-ldp-igp-synchronization/comment-page-1/#comment-302 shivlu jain Fri, 06 Mar 2009 08:40:11 +0000 http://www.hauwaerts.be/?p=766#comment-302 I have one concern:- During the time of LDP & IGP Sync what will be the flow of my IP traffic. I have one concern:-
During the time of LDP & IGP Sync what will be the flow of my IP traffic.

]]> By: Follow up on MPLS LDP-IGP synchronization | Geert's blog - Casu Consulto http://www.hauwaerts.be/2009/02/22/mpls-ldp-igp-synchronization/comment-page-1/#comment-281 Follow up on MPLS LDP-IGP synchronization | Geert's blog - Casu Consulto Wed, 04 Mar 2009 17:36:06 +0000 http://www.hauwaerts.be/?p=766#comment-281 [...] recent blogpost about the subject explains the issue and the solution to prevent an IP link from being used while LDP is not fully [...] [...] recent blogpost about the subject explains the issue and the solution to prevent an IP link from being used while LDP is not fully [...]

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